Reference: parameters (GUC) =========================== add_missing_from ----------------- Automatically adds missing table references to FROM clauses. Present for compatibility with releases of PostgreSQL prior to 8.1, where this behavior was allowed by default. ============= ======= ======================= Value Range Default Set Classifications ============= ======= ======================= Boolean off master, session, reload ============= ======= ======================= application_name ----------------- Sets the application name for a client session. For example, if connecting via psql, this will be set to psql. Setting an application name allows it to be reported in log messages and statistics views. ============ ========= ======================= Value Range Default Set Classifications ============ ========= ======================= String master, session, reload ============ ========= ======================= array_nulls ------------ This controls whether the array input parser recognizes unquoted NULL as specifying a null array element. By default, this is on, allowing array values containing null values to be entered. ============ ========= ======================= Value Range Default Set Classifications ============ ========= ======================= String on master, session, reload ============ ========= ======================= authentication_timeout ----------------------- Maximum time to complete client authentication. This prevents hung clients from occupying a connection indefinitely. ============================================ ======= ======================= Value Range Default Set Classifications ============================================ ======= ======================= Any valid time expression (number and unit) 1min local, system, restart ============================================ ======= ======================= autocompact_disabled ----------------------- disable autocompaction on appendonly table =========== ======= ======================= Value Range Default Set Classifications =========== ======= ======================= Boolean off master, session, reload =========== ======= ======================= backslash_quote ---------------- This controls whether a quote mark can be represented by \' in a string literal. The preferred, SQL-standard way to represent a quote mark is by doubling it ('') but PostgreSQL has historically also accepted \'. However, use of \' creates security risks because in some client character set encodings, there are multibyte characters in which the last byte is numerically equivalent to ASCII \. =================================================================================================== =================== ======================= Value Range Default Set Classifications =================================================================================================== =================== ======================= on (allow \' always) off (reject always) safe_encoding (allow only if client encoding does not allow ASCII \ within a multibyte character) safe_encoding master, session, reload =================================================================================================== =================== ======================= block_size ---------- Reports the size of a disk block. ================ ======= ======================= Value Range Default Set Classifications ================ ======= ======================= number of bytes 32768 read only ================ ======= ======================= bonjour_name ------------- Specifies the Bonjour broadcast name. By default, the computer name is used, specified as an empty string. This option is ignored if the server was not compiled with Bonjour support. ============== ======= ======================= Value Range Default Set Classifications ============== ======= ======================= String unset master, system, restart ============== ======= ======================= cache_read_protocols ---------------------- Specifies the stroage which should be cached by `CacheServer <./cache-server.html>`_ 。 ============= ======= ======================= Value Range Default Set Classifications ============= ======= ======================= String s3 master, session, reload ============= ======= ======================= cache_tables ---------------------- Specifies the tables which should be cached by `CacheServer <./cache-server.html>`_ 。 ============= ====================== ======================= Value Range Default Set Classifications ============= ====================== ======================= String cache_server_cache_all master, session, reload ============= ====================== ======================= check_function_bodies ---------------------- When set to off, disables validation of the function body string during CREATE FUNCTION. Disabling validation is occasionally useful to avoid problems such as forward references when restoring function definitions from a dump. ============= ======= ======================= Value Range Default Set Classifications ============= ======= ======================= Boolean on master, session, reload ============= ======= ======================= client_encoding ---------------- Sets the client-side encoding (character set). The default is to use the same as the database encoding. See Supported Character Sets in the PostgreSQL documentation. ============= ======= ======================= Value Range Default Set Classifications ============= ======= ======================= character set UTF8 master, session, reload ============= ======= ======================= client_min_messages -------------------- Controls which message levels are sent to the client. Each level includes all the levels that follow it. The later the level, the fewer messages are sent. ============= ======= ======================= Value Range Default Set Classifications ============= ======= ======================= DEBUG5 DEBUG4 DEBUG3 DEBUG2 NOTICE master, session, reload DEBUG1 LOG NOTICE WARNING ERROR FATAL PANIC ============= ======= ======================= clusterName ----------- Corresponding identifier for this OushuDB cluster in oushu cloud system. ============ ========= ======================== Value Range Default Set Classifications ============ ========= ======================== String "" master, system, restart ============ ========= ======================== cpu_index_tuple_cost --------------------- For the legacy query optimizer (planner), sets the estimate of the cost of processing each index row during an index scan. This is measured as a fraction of the cost of a sequential page fetch. ============== ======= ======================= Value Range Default Set Classifications ============== ======= ======================= floating point 0.005 master, session, reload ============== ======= ======================= cpu_operator_cost ------------------ For the optimizer (planner), sets the estimate of the cost of processing each operator in a WHERE clause. This is measured as a fraction of the cost of a sequential page fetch. ============== ======= ======================= Value Range Default Set Classifications ============== ======= ======================= floating point 0.0025 master, session, reload ============== ======= ======================= cpu_tuple_cost --------------- For the optimizer (planner), Sets the estimate of the cost of processing each row during a query. This is measured as a fraction of the cost of a sequential page fetch. ============== ======= ======================= Value Range Default Set Classifications ============== ======= ======================= floating point 0.01 master, session, reload ============== ======= ======================= cursor_tuple_fraction ---------------------- Tells the optimizer (planner) how many rows are expected to be fetched in a cursor query, thereby allowing the legacy optimizer to use this information to optimize the query plan. The default of 1 means all rows will be fetched. ============== ======= ======================= Value Range Default Set Classifications ============== ======= ======================= integer 1 master, session, reload ============== ======= ======================= custom_variable_classes ------------------------ Specifies one or several class names to be used for custom variables. A custom variable is a variable not normally known to the server but used by some add-on modules. Such variables must have names consisting of a class name, a dot, and a variable name. ==================================== ======= ======================= Value Range Default Set Classifications ==================================== ======= ======================= comma-separated list of class names unset local, system, restart ==================================== ======= ======================= DateStyle --------- Sets the display format for date and time values, as well as the rules for interpreting ambiguous date input values. This variable contains two independent components: the output format specification and the input/output specification for year/month/day ordering. ==================================== ======== ======================= Value Range Default Set Classifications ==================================== ======== ======================= , where: is ISO, Postgres, SQL, or German ISO, MDY master, session, reload is DMY, MDY, or YMD ==================================== ======== ======================= db_user_namespace ------------------ This enables per-database user names. If on, you should create users as username@dbname. To create ordinary global users, simply append @ when specifying the user name in the client. ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= Boolean off local, system, restart ============ ======= ======================= deadlock_timeout ----------------- The time, in milliseconds, to wait on a lock before checking to see if there is a deadlock condition. On a heavily loaded server you might want to raise this value. Ideally the setting should exceed your typical transaction time, so as to improve the odds that a lock will be released before the waiter decides to check for deadlock. ======================= ======= ======================= Value Range Default Set Classifications ======================= ======= ======================= integer (milliseconds) 1000 local, system, restart ======================= ======= ======================= debug_assertions ----------------- Turns on various assertion checks. ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= Boolean off local, system, restart ============ ======= ======================= debug_pretty_print ------------------- Indents debug output to produce a more readable but much longer output format. client_min_messages or log_min_messages must be DEBUG1 or lower. ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= Boolean off master, session, reload ============ ======= ======================= debug_print_parse ------------------ For each executed query, prints the resulting parse tree. client_min_messages or log_min_messages must be DEBUG1 or lower. ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= Boolean off master, session, reload ============ ======= ======================= debug_print_plan ----------------- For each executed query, prints the OushuDB parallel query execution plan. client_min_messages or log_min_messages must be DEBUG1 or lower. ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= Boolean off master, session, reload ============ ======= ======================= debug_print_prelim_plan ------------------------ For each executed query, prints the preliminary query plan. client_min_messages or log_min_messages must be DEBUG1 or lower. ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= Boolean off master, session, reload ============ ======= ======================= debug_print_rewritten ---------------------- For each executed query, prints the query rewriter output. client_min_messages or log_min_messages must be DEBUG1 or lower. ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= Boolean off master, session, reload ============ ======= ======================= debug_print_slice_table ------------------------ For each executed query, prints the OushuDB query slice plan. client_min_messages or log_min_messages must be DEBUG1 or lower. ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= Boolean off master, session, reload ============ ======= ======================= debug_udf_plan -------------- Log out the plans of statements in UDF for debug. ============= ======= ======================= Value Range Default Set Classifications ============= ======= ======================= Boolean false master, session, reload ============= ======= ======================= default_statement_mem ---------------------- The default amount of memory, in KB, to allocate to query statements that do not require any segment resources and are executed only on the master host. This type of query execution is rare in OushuDB. The default value of this configuration parameter is acceptable for most deployments. Modify this value only if you are using an advanced configuration. ============== ======= ======================= Value Range Default Set Classifications ============== ======= ======================= integer > 1000 128000 master, session, reload ============== ======= ======================= default_statistics_target -------------------------- Sets the default statistics target for table columns that have not had a column-specific target set via ALTER TABLE SET STATISTICS. Larger values increase the time needed to do ANALYZE, but may improve the quality of the legacy query optimizer (planner) estimates. ============== ======= ======================= Value Range Default Set Classifications ============== ======= ======================= integer > 0 25 master, session, reload ============== ======= ======================= default_tablespace ------------------- The default tablespace in which to create objects (tables and indexes) when a CREATE command does not explicitly specify a tablespace. ==================== ======= ======================= Value Range Default Set Classifications ==================== ======= ======================= name of a tablespace unset master, session, reload ==================== ======= ======================= default_storage -------------------- Sets the default storage when creating table.The option is hdfs, s3 or magma. ============ ========== ======================== Value Range Default Set Classifications ============ ========== ======================== String hdfs master, session , reload ============ ========== ======================== default_transaction_isolation ------------------------------ Controls the default isolation level of each new transaction. ==================== =============== ======================= Value Range Default Set Classifications ==================== =============== ======================= read committed read uncommitted read committed master, session, reload repeatable read serializable ==================== =============== ======================= default_transaction_read_only ------------------------------ Controls the default read-only status of each new transaction. A read-only SQL transaction cannot alter non-temporary tables. ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= Boolean off master, session, reload ============ ======= ======================= dfs_url -------- See hawq_dfs_url. dynamic_library_path --------------------- If a dynamically loadable module needs to be opened and the file name specified in the CREATE FUNCTION or LOAD command does not have a directory component (i.e. the name does not contain a slash), the system will search this path for the required file. The compiled-in PostgreSQL package library directory is substituted for $libdir. This is where the modules provided by the standard PostgreSQL distribution are installed. ======================================================= ======= ======================= Value Range Default Set Classifications ======================================================= ======= ======================= a list of absolute directory paths separated by colons $libdir master, session, reload ======================================================= ======= ======================= effective_cache_size --------------------- Sets the assumption about the effective size of the disk cache that is available to a single query for the legacy query optimizer (planner). This is factored into estimates of the cost of using an index; a higher value makes it more likely index scans will be used, a lower value makes it more likely sequential scans will be used. This parameter has no effect on the size of shared memory allocated by a OushuDB server instance, nor does it reserve kernel disk cache; it is used only for estimation purposes. ============== ======= ======================= Value Range Default Set Classifications ============== ======= ======================= floating point 512MB master, session, reload ============== ======= ======================= enable_bitmapscan ----------------- Enables or disables the use of bitmap-scan plan types by the legacy query optimizer (planner). Note that this is different than a Bitmap Index Scan. A Bitmap Scan means that indexes will be dynamically converted to bitmaps in memory when appropriate, giving faster index performance on complex queries against very large tables. It is used when there are multiple predicates on different indexed columns. Each bitmap per column can be compared to create a final list of selected tuples. ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= Boolean on master, session, reload ============ ======= ======================= enable_groupagg ---------------- Enables or disables the use of group aggregation plan types by the legacy query optimizer (planner). ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= Boolean on master, session, reload ============ ======= ======================= enable_hashagg --------------- Enables or disables the use of hash aggregation plan types by the legacy query optimizer (planner). ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= Boolean on master, session, reload ============ ======= ======================= enable_hashjoin ---------------- Enables or disables the use of hash-join plan types by the legacy query optimizer (planner). ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= Boolean on master, session, reload ============ ======= ======================= enable_indexscan ----------------- Enables or disables the use of index-scan plan types by the legacy query optimizer (planner). ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= Boolean on master, session, reload ============ ======= ======================= enable_magma_bitmapscan ----------------------- Enable magma-bitmap-scan plan. ============= ======= ======================= Value Range Default Set Classifications ============= ======= ======================= Boolean false master, session, reload ============= ======= ======================= enable_magma_indexonlyscan -------------------------- Enable magma-indexonly-scan. ============= ======= ======================= Value Range Default Set Classifications ============= ======= ======================= Boolean true master, session, reload ============= ======= ======================= enable_magma_indexscan ---------------------- Enable magma-index-scan. ============= ======= ======================= Value Range Default Set Classifications ============= ======= ======================= Boolean true master, session, reload ============= ======= ======================= enable_master_auto_ha --------------------- Enable standby to be active automatically when master fails. ============= ======= ======================= Value Range Default Set Classifications ============= ======= ======================= Boolean false master, session, reload ============= ======= ======================= enable_mergejoin ---------------- Enables or disables the use of merge-join plan types by the legacy query optimizer (planner). Merge join is based on the idea of sorting the left- and right-hand tables into order and then scanning them in parallel. So, both data types must be capable of being fully ordered, and the join operator must be one that can only succeed for pairs of values that fall at the ‘same place’ in the sort order. In practice this means that the join operator must behave like equality. ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= Boolean off master, session, reload ============ ======= ======================= enable_nestloop ---------------- Enables or disables the use of nested-loop join plans by the legacy query optimizer (planner). It’s not possible to suppress nested-loop joins entirely, but turning this variable off discourages the legacy optimizer from using one if there are other methods available. ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= Boolean off master, session, reload ============ ======= ======================= enable_pg_stat_activity_history -------------------------------- Set enable_pg_stat_activity_history to track SQL execution history. ============= ======= ======================= Value Range Default Set Classifications ============= ======= ======================= Boolean false master, session, reload ============= ======= ======================= enable_secure_filesystem ---------------------------- Enables or disables access to a secure HDFS file system. To enable Kerberos security for HDFS, set this configuration parameter to on before starting OushuDB. ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= Boolean off master, session, reload ============ ======= ======================= enable_seqscan --------------- Enables or disables the use of sequential scan plan types by the legacy query optimizer (planner). It’s not possible to suppress sequential scans entirely, but turning this variable off discourages the legacy optimizer from using one if there are other methods available. ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= Boolean on master, session, reload ============ ======= ======================= enable_sort ----------- Enables or disables the use of explicit sort steps by the query optimizer (planner). It’s not possible to suppress explicit sorts entirely, but turning this variable off discourages the legacy optimizer from using one if there are other methods available. ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= Boolean on master, session, reload ============ ======= ======================= enable_tidscan --------------- Enables or disables the use of tuple identifier (TID) scan plan types by the legacy query optimizer (planner). ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= Boolean on master, session, reload ============ ======= ======================= escape_string_warning ---------------------- When on, a warning is issued if a backslash (\) appears in an ordinary string literal (’…’ syntax). Escape string syntax (E’…’) should be used for escapes, because in future versions, ordinary strings will have the SQL standard-conforming behavior of treating backslashes literally. ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= Boolean on master, session, reload ============ ======= ======================= explain_memory_verbosity ------------------------- Controls the granularity of memory information displayed in EXPLAIN ANALYZE output. explain_memory_verbosity takes three values: * SUPPRESS - generate only total memory information for the whole query * SUMMARY - generate basic memory information for each executor node * DETAIL - generate detailed memory information for each executor node ============ ======== ==================== Value Range Default Set Classifications ============ ======== ==================== SUPPRESS

SUMMARY SUPPRESS master DETAIL ============ ======== ==================== explain_pretty_print --------------------- Determines whether EXPLAIN VERBOSE uses the indented or non-indented format for displaying detailed query-tree dumps. ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= Boolean on master, session, reload ============ ======= ======================= external_catalog_hive_database --------------------------------------- Determines which hive database is accessed. ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= String default master, session, reload ============ ======= ======================= external_catalog_hive_authorization -------------------------------------------- Determines whether to use hive authorization. ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= String master, session, reload ============ ======= ======================= external_catalog_hs2_url --------------------------------------- Determines the url of hs2 thrift serice. ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= String master, session, reload ============ ======= ======================= extra_float_digits -------------------- Adjusts the number of digits displayed for floating-point values, including float4, float8, and geometric data types. The parameter value is added to the standard number of digits. The value can be set as high as 2, to include partially-significant digits; this is especially useful for dumping float data that needs to be restored exactly. Or it can be set negative to suppress unwanted digits. ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= integer 0 master, session, reload ============ ======= ======================= from_collapse_limit -------------------- The query optimizer (planner) will merge sub-queries into upper queries if the resulting FROM list would have no more than this many items. Smaller values reduce planning time but may yield inferior query plans. ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= integer(1-n) 20 master, session, reload ============ ======= ======================= gp_adjust_selectivity_for_outerjoins ------------------------------------- Enables the selectivity of NULL tests over outer joins. ============ ======= ======================= Value Range Default Set Classifications ============ ======= ======================= Boolean on master, session, reload ============ ======= ======================= gp_analyze_relative_error -------------------------- Sets the estimated acceptable error in the cardinality of the table “ a value of 0.5 is supposed to be equivalent to an acceptable error of 50% (this is the default value used in PostgreSQL). If the statistics collected during ANALYZE are not producing good estimates of cardinality for a particular table attribute, decreasing the relative error fraction (accepting less error) tells the system to sample more rows. ===================== ======= ======================= Value Range Default Set Classifications ===================== ======= ======================= floating point < 1.0 0.25 master, session, reload ===================== ======= ======================= autostat_disabled ------------------ Specifies the mode for triggering automatic statistics collection with ANALYZE. The 'OFF' option triggers statistics collection for CREATE TABLE AS SELECT, INSERT, COPY, UPDATE, DELETE or some partition DDLs operations on any inner tables if necessary. Warning: Depending on the specific nature of your database operations, automatic statistics collection can have a negative performance impact. Carefully evaluate whether 'ON' is appropriate for your system. :: CREATE TABLE AS SELECT INSERT COPY UPDATE DELETE Default is ON. Note: For partitioned tables, automatic statistics collections for leaf partitions are triggered even if data is inserted from the top-level parent table of a partitioned table. Note: Auto analyze is only enabled for tables which have been analyzed(manual ANALYZE or ANALYZE triggered by autostat_on_no_stat). ============ =========== ======================= Value Range Default Set Classifications ============ =========== ======================= on on master, session, reload off ============ =========== ======================= autostat_on_no_stat ------------------------------------ Specifies the mode for triggering automatic statistics collection with ANALYZE. The on option triggers statistics collection for CREATE TABLE AS SELECT, INSERT, or COPY operations on any table that has no existing statistics. Note: The ANALYZE triggered by autostat_on_no_stat will be executed in current session. ============ =========== ======================= Value Range Default Set Classifications ============ =========== ======================= on off master, session, reload off ============ =========== ======================= autostat_threshold --------------------------------- Specifies the threshold for automatic statistics collection when autostat_disabled is set to "OFF". Note: For non-dynamic-partitioned tables, if the number of affected rows are equal to or greater than autostat_scale * reltuples + autostat_threshold, auto analyze will be triggered. reltuples is the number of rows calculated by last ANALYZE. ============= =========== ======================= Value Range Default Set Classifications ============= =========== ======================= integer 1000 master, reload ============= =========== ======================= autostat_scale --------------------------------- Specifies the scale that number of tuple affected prior to auto analyze as a fraction of reltuples. ============= =========== ======================= Value Range Default Set Classifications ============= =========== ======================= double 0.2 master, reload ============= =========== ======================= autostat_dynpart_threshold --------------------------------- Specifies the threshold for automatic statistics collection when autostat_disabled is set to "OFF". Note: For dynamic-partitioned tables, if the number of affected rows are equal to or greater than autostat_dynpart_threshold, auto analyze will be triggered. ============= =========== ======================= Value Range Default Set Classifications ============= =========== ======================= integer 500000 master, reload ============= =========== ======================= autostat_shmem_ringqueue_size --------------------------------- Specifies the size of shared memroy reserved for autostat reports. Note: unit is MB. ============= =========== ======================= Value Range Default Set Classifications ============= =========== ======================= integer 128 master ============= =========== ======================= autostat_flush_interval --------------------------------- Specifies the interval of flushing autostat reports to metadata clusters. Note: unit is second. ============= =========== ======================= Value Range Default Set Classifications ============= =========== ======================= integer 10 master, session, reload ============= =========== ======================= autostat_time_windows --------------------------------- Specifies the time windows that auto analayze can be triggered. ============= =========== ======================= Value Range Default Set Classifications ============= =========== ======================= String 00:00-23:59 master, reload ============= =========== ======================= autostat_max_workers --------------------------------- Specifies the maximum number of background workers that perform auto analayzes. ============= =========== ======================= Value Range Default Set Classifications ============= =========== ======================= int 4 master, reload ============= =========== ======================= autostat_allow_nonowner --------------------------------- Specifies if auto analayzes can be triggered by users who don't own the relation. ============= =========== ========================== Value Range Default Set Classifications ============= =========== ========================== on, off off master, session, superuser ============= =========== ========================== gp_backup_directIO ------------------- Direct I/O allows OushuDB to bypass the buffering of memory within the file system cache for backup. When Direct I/O is used for a file, data is transferred directly from the disk to the application buffer, without the use of the file buffer cache. Direct I/O is supported only on Red Hat Enterprise Linux, CentOS, and SUSE. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= on, off off master, session, reload ============= ======== ======================= gp_backup_directIO_read_chunk_mb --------------------------------- Sets the chunk size in MB when Direct I/O is enabled with gp_backup_directIO. The default chunk size is 20MB. The default value is the optimal setting. Decreasing it will increase the backup time and increasing it will result in little change to backup time. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= 1-200 20MB master, session, reload ============= ======== ======================= gp_cached_segworkers_threshold ------------------------------- When a user starts a session with OushuDB and issues a query, the system creates groups or 'gangs’ of worker processes on each segment to do the work. After the work is done, the segment worker processes are destroyed except for a cached number which is set by this parameter. A lower setting conserves system resources on the segment hosts, but a higher setting may improve performance for power-users that want to issue many complex queries in a row. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= integer > 0 5 master, session, reload ============= ======== ======================= gp_command_count ----------------- Shows how many commands the master has received from the client. Note that a single SQL command might actually involve more than one command internally, so the counter may increment by more than one for a single query. This counter also is shared by all of the segment processes working on the command. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= integer > 0 1 read only ============= ======== ======================= gp_connections_per_thread -------------------------- A value larger than or equal to the number of segments means that each slice in a query plan will get its own thread when dispatching to the segments. A value of 0 indicates that the dispatcher should use a single thread when dispatching all query plan slices to a segment. Lower values will use more threads, which utilizes more resources on the master. Typically, the default does not need to be changed unless there is a known throughput performance problem. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= integer 64 master, session, reload ============= ======== ======================= gp_debug_linger ---------------- Number of seconds for a OushuDB process to linger after a fatal internal error. =========================================== ======== ======================= Value Range Default Set Classifications =========================================== ======== ======================= Any valid time expression (number and unit) 0 master, session, reload =========================================== ======== ======================= gp_dynamic_partition_pruning ----------------------------- Enables plans that can dynamically eliminate the scanning of partitions. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= on/off on master, session, reload ============= ======== ======================= gp_enable_agg_distinct ----------------------- Enables or disables two-phase aggregation to compute a single distinct-qualified aggregate. This applies only to subqueries that include a single distinct-qualified aggregate function. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= Boolean on master, session, reload ============= ======== ======================= gp_enable_agg_distinct_pruning ------------------------------- Enables or disables three-phase aggregation and join to compute distinct-qualified aggregates. This applies only to subqueries that include one or more distinct-qualified aggregate functions. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= Boolean on master, session, reload ============= ======== ======================= gp_enable_direct_dispatch -------------------------- Enables or disables the dispatching of targeted query plans for queries that access data on a single segment. When on, queries that target rows on a single segment will only have their query plan dispatched to that segment (rather than to all segments). This significantly reduces the response time of qualifying queries as there is no interconnect setup involved. Direct dispatch does require more CPU utilization on the master. ============= ======== ======================== Value Range Default Set Classifications ============= ======== ======================== Boolean on master, session, restart ============= ======== ======================== gp_enable_fallback_plan ------------------------ Allows use of disabled plan types when a query would not be feasible without them. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= Boolean on master, session, reload ============= ======== ======================= gp_enable_fast_sri ------------------- When set to on, the query optimizer (planner) plans single row inserts so that they are sent directly to the correct segment instance (no motion operation required). This significantly improves performance of single-row-insert statements. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= Boolean on master, session, reload ============= ======== ======================= gp_enable_groupext_distinct_gather ----------------------------------- Enables or disables gathering data to a single node to compute distinct-qualified aggregates on grouping extension queries. When this parameter and gp_enable_groupext_distinct_pruning are both enabled, the legacy query optimizer (planner) uses the cheaper plan. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= Boolean on master, session, reload ============= ======== ======================= gp_enable_groupext_distinct_pruning ------------------------------------ Enables or disables three-phase aggregation and join to compute distinct-qualified aggregates on grouping extension queries. Usually, enabling this parameter generates a cheaper query plan that the legacy query optimizer (planner) will use in preference to existing plan. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= Boolean on master, session, reload ============= ======== ======================= gp_enable_multiphase_agg ------------------------- Enables or disables the use of two or three-stage parallel aggregation plans legacy query optimizer (planner). This approach applies to any subquery with aggregation. If gp_enable_multiphase_agg is off, thengp_enable_agg_distinct and gp_enable_agg_distinct_pruning are disabled. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= Boolean on master, session, reload ============= ======== ======================= gp_enable_predicate_propagation -------------------------------- When enabled, the legacy query optimizer (planner) applies query predicates to both table expressions in cases where the tables are joined on their distribution key column(s). Filtering both tables prior to doing the join (when possible) is more efficient. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= Boolean on master, session, reload ============= ======== ======================= gp_enable_preunique -------------------- Enables two-phase duplicate removal for SELECT DISTINCT queries (not SELECT COUNT(DISTINCT)). When enabled, it adds an extra SORT DISTINCT set of plan nodes before motioning. In cases where the distinct operation greatly reduces the number of rows, this extra SORT DISTINCT is much cheaper than the cost of sending the rows across the Interconnect. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= Boolean on master, session, reload ============= ======== ======================= gp_enable_sequential_window_plans ---------------------------------- If on, enables non-parallel (sequential) query plans for queries containing window function calls. If off, evaluates compatible window functions in parallel and rejoins the results. This is an experimental parameter. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= Boolean on master, session, reload ============= ======== ======================= gp_enable_sort_distinct ------------------------ Enable duplicates to be removed while sorting. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= Boolean on master, session, reload ============= ======== ======================= gp_enable_sort_limit --------------------- Enable LIMIT operation to be performed while sorting. Sorts more efficiently when the plan requires the first limit_number of rows at most. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= Boolean on master, session, reload ============= ======== ======================= gp_external_enable_exec ------------------------ Enables or disables the use of external tables that execute OS commands or scripts on the segment hosts (CREATE EXTERNAL TABLE EXECUTE syntax). ============= ======== ======================== Value Range Default Set Classifications ============= ======== ======================== Boolean on master, session, restart ============= ======== ======================== gp_external_grant_privileges ----------------------------- Enables or disables non-superusers to issue a CREATE EXTERNAL [WEB] TABLE command in cases where the LOCATION clause specifies specifies http or gpfdist. The ability to create an external table can be granted to a role using CREATE ROLE or ALTER ROLE. ============= ======== ======================== Value Range Default Set Classifications ============= ======== ======================== Boolean off master, session, restart ============= ======== ======================== gp_external_max_segs --------------------- Sets the number of segments that will scan external table data during an external table operation, the purpose being not to overload the system with scanning data and take away resources from other concurrent operations. This only applies to external tables that use the gpfdist:// protocol to access external table data. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= integer 64 master, session, reload ============= ======== ======================= gp_hashjoin_tuples_per_bucket ------------------------------ Sets the target density of the hash table used by HashJoin operations. A smaller value will tend to produce larger hash tables, which can increase join performance. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= integer 5 master, session, reload ============= ======== ======================= gp_idf_deduplicate ------------------- Changes the strategy to compute and process MEDIAN, and PERCENTILE_DISC. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= auto none auto master, session, reload force ============= ======== ======================= gp_interconnect_fc_method --------------------------- Specifies the flow control method used for UDP interconnect when the value of gp_interconnect_type is UDPIFC. For capacity based flow control, senders do not send packets when receivers do not have the capacity. Loss based flow control is based on capacity based flow control, and also tunes the sending speed according to packet losses. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= CAPACITY LOSS LOSS master, session, reload ============= ======== ======================= gp_interconnect_hash_multiplier -------------------------------- Sets the size of the hash table used by the UDP interconnect to track connections. This number is multiplied by the number of segments to determine the number of buckets in the hash table. Increasing the value may increase interconnect performance for complex multi-slice queries (while consuming slightly more memory on the segment hosts). ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= 2-25 2 master, session, reload ============= ======== ======================= gp_interconnect_queue_depth ---------------------------- Sets the amount of data per-peer to be queued by the UDP interconnect on receivers (when data is received but no space is available to receive it the data will be dropped, and the transmitter will need to resend it). Increasing the depth from its default value will cause the system to use more memory; but may increase performance. It is reasonable for this to be set between 1 and 10. Queries with data skew potentially perform better when this is increased. Increasing this may radically increase the amount of memory used by the system. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= 1-2048 4 master, session, reload ============= ======== ======================= gp_interconnect_setup_timeout ------------------------------ When the interconnect type is UDP, the time to wait for the Interconnect to complete setup before it times out. This parameter is used only when gp_interconnect_type is set to UDP. =========================================== ======== ======================= Value Range Default Set Classifications =========================================== ======== ======================= Any valid time expression (number and unit) 2 hours master, session, reload =========================================== ======== ======================= gp_interconnect_snd_queue_depth -------------------------------- Sets the amount of data per-peer to be queued by the UDP interconnect on senders. Increasing the depth from its default value will cause the system to use more memory; but may increase performance. Reasonable values for this parameter are between 1 and 4. Increasing the value might radically increase the amount of memory used by the system. This parameter is used only when gp_interconnect_type is set to UDPIFC. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= 1-4096 2 master, session, reload ============= ======== ======================= gp_interconnect_type -------------------- Sets the networking protocol used for Interconnect traffic. With the TCP protocol, OushuDB has an upper limit of 1000 segment instances - less than that if the query workload involves complex, multi-slice queries. UDP allows for greater interconnect scalability. Note that the OushuDB software does the additional packet verification and checking not performed by UDP, so reliability and performance is equivalent to TCP. Specify the UDP interconnect flow control method with gp_interconnect_fc_method.

============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= TCP UDP UDP local, system, restart ============= ======== ======================= gp_log_format -------------- Specifies the format of the server log files. If using hawq_toolkit administrative schema, the log files must be in CSV format. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= csv text csv local, system, restart ============= ======== ======================= gp_max_csv_line_length ----------------------- The maximum length of a line in a CSV formatted file that will be imported into the system. The default is 1MB (1048576 bytes). Maximum allowed is 4MB (4194184 bytes). The default may need to be increased if using the hawq_toolkit administrative schema to read OushuDB log files. =============== ======== ======================= Value Range Default Set Classifications =============== ======== ======================= number of bytes 1048576 local, system, restart =============== ======== ======================= gp_max_databases ----------------- The maximum number of databases allowed in a OushuDB system. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= integer 16 master, session, reload ============= ======== ======================= gp_max_filespaces ------------------ The maximum number of filespaces allowed in a OushuDB system. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= integer 8 master, session, reload ============= ======== ======================= gp_max_packet_size ------------------ Sets the size (in bytes) of messages sent by the UDP interconnect, and sets the tuple-serialization chunk size for both the UDP and TCP interconnect. ============= ======== ======================= Value Range Default Set Classifications ============= ======== ======================= 512-65536 8192 master, system, restart ============= ======== ======================= gp_max_plan_size ------------------ Specifies the total maximum uncompressed size of a query execution plan multiplied by the number of Motion operators (slices) in the plan. If the size of the query plan exceeds the value, the query is cancelled and an error is returned. A value of 0 means that the size of the plan is not monitored. You can specify a value in KB,MB, or GB. The default unit is KB. For example, a value of 200 is 200KB. A value of 1GB is the same as 1024MB or 1048576KB. ============= ======== ========================== Value Range Default Set Classifications ============= ======== ========================== integer 0 master, session, superuser ============= ======== ========================== gp_max_tablespaces ------------------- The maximum number of tablespaces allowed in a OushuDB system. ============= ======== ========================== Value Range Default Set Classifications ============= ======== ========================== integer 16 master, session, superuser ============= ======== ========================== gp_motion_cost_per_row ----------------------- Sets the legacy query optimizer (planner) cost estimate for a Motion operator to transfer a row from one segment to another, measured as a fraction of the cost of a sequential page fetch. If 0, then the value used is two times the value of cpu_tuple_cost. ============== ======== ========================== Value Range Default Set Classifications ============== ======== ========================== floating point 0 master, session, reload ============== ======== ========================== gp_reject_percent_threshold ---------------------------- For single row error handling on COPY and external table SELECTs, sets the number of rows processed before SEGMENT REJECT LIMIT n PERCENT starts calculating. ============== ======== ========================== Value Range Default Set Classifications ============== ======== ========================== integer (1-n) 300 master, session, reload ============== ======== ========================== gp_reraise_signal ------------------ If enabled, will attempt to dump core if a fatal server error occurs. ============== ======== ========================== Value Range Default Set Classifications ============== ======== ========================== Boolean on master, session, reload ============== ======== ========================== gp_role --------- The role of this server process ” set to dispatch for the master and execute for a segment. ============== ======== ========================== Value Range Default Set Classifications ============== ======== ========================== dispatch execute utility read only read only ============== ======== ========================== gp_safefswritesize -------------------- Specifies a minimum size for safe write operations to append-only tables in a non-mature file system. When a number of bytes greater than zero is specified, the append-only writer adds padding data up to that number in order to prevent data corruption due to file system errors. Each non-mature file system has a known safe write size that must be specified here when using OushuDB with that type of file system. This is commonly set to a multiple of the extent size of the file system; for example, Linux ext3 is 4096 bytes, so a value of 32768 is commonly used. ============== ======== ========================== Value Range Default Set Classifications ============== ======== ========================== integer 0 local, system, restart ============== ======== ========================== gp_segment_connect_timeout --------------------------- Time that the OushuDB interconnect will try to connect to a segment instance over the network before timing out. Controls the network connection timeout between master and segment replication processes. =========================================== ======== ========================== Value Range Default Set Classifications =========================================== ======== ========================== Any valid time expression (number and unit) 10min local, system, reload =========================================== ======== ========================== gp_segments_for_planner ------------------------ Sets the number of segment instances for the query optimizer (planner) to assume in its cost and size estimates. If 0, then the value used is the actual number of segments. This variable affects the legacy optimizer’s estimates of the number of rows handled by each sending and receiving process in Motion operators. ============== ======== ========================== Value Range Default Set Classifications ============== ======== ========================== integer 0 master, session, reload ============== ======== ========================== gp_session_id -------------- A system assigned ID number for a client session. Starts counting from 1 when the master instance is first started. ============== ======== ========================== Value Range Default Set Classifications ============== ======== ========================== integer(1-n) 14 read only ============== ======== ========================== gp_set_proc_affinity --------------------- If enabled, when a OushuDB server process (postmaster) is started it will bind to a CPU. ============== ======== ========================== Value Range Default Set Classifications ============== ======== ========================== Boolean off master, system, restart ============== ======== ========================== gp_set_read_only ----------------- Set to on to disable writes to the database. Any in progress transactions must finish before read-only mode takes affect. ============== ======== ========================== Value Range Default Set Classifications ============== ======== ========================== Boolean off master, session, reload ============== ======== ========================== gp_statistics_pullup_from_child_partition ------------------------------------------ Enables the use of statistics from child tables when planning queries on the parent table by the query optimizer (planner). ============== ======== ========================== Value Range Default Set Classifications ============== ======== ========================== Boolean on master, session, reload ============== ======== ========================== gp_statistics_use_fkeys ----------------------- When enabled, allows the query optimizer (planner) to use foreign key information stored in the system catalog to optimize joins between foreign keys and primary keys. ============== ======== ========================== Value Range Default Set Classifications ============== ======== ========================== Boolean on master, session, reload ============== ======== ========================== gp_vmem_idle_resource_timeout ----------------------------- Sets the time in milliseconds a session can be idle before gangs on the segment databases are released to free up resources. ====================== ======== ========================== Value Range Default Set Classifications ====================== ======== ========================== number of milliseconds 18000 master, system, restart ====================== ======== ========================== gp_vmem_protect_segworker_cache_limit -------------------------------------- If a query executor process consumes more than this configured amount, then the process will not be cached for use in subsequent queries after the process completes. Systems with lots of connections or idle processes may want to reduce this number to free more memory on the segments. Note that this is a local parameter and must be set for every segment. ====================== ======== ========================== Value Range Default Set Classifications ====================== ======== ========================== number of megabytes 500 local, system, restart ====================== ======== ========================== gp_workfile_checksumming ------------------------- Adds a checksum value to each block of a work file (or spill file) used by HashAgg and HashJoin query operators. This adds an additional safeguard from faulty OS disk drivers writing corrupted blocks to disk. When a checksum operation fails, the query will cancel and rollback rather than potentially writing bad data to disk. ============== ======== ========================== Value Range Default Set Classifications ============== ======== ========================== Boolean on master, session, reload ============== ======== ========================== gp_workfile_compress_algorithm ------------------------------- When a hash aggregation or hash join operation spills to disk during query processing, specifies the compression algorithm to use on the spill files. If using zlib, it must be in your $PATH on all segments. If your OushuDB database installation uses serial ATA (SATA) disk drives, setting the value of this parameter to zlib might help to avoid overloading the disk subsystem with IO operations. ============== ======== ========================== Value Range Default Set Classifications ============== ======== ========================== none zlib none master, session, reload ============== ======== ========================== gp_workfile_limit_files_per_query --------------------------------- Sets the maximum number of temporary spill files (also known as workfiles) allowed per query per segment. Spill files are created when executing a query that requires more memory than it is allocated. The current query is terminated when the limit is exceeded. Set the value to 0 (zero) to allow an unlimited number of spill files. master session reload ============== ======== ========================== Value Range Default Set Classifications ============== ======== ========================== integer 3000000 master, session, reload ============== ======== ========================== gp_workfile_limit_per_query ---------------------------- Sets the maximum disk size an individual query is allowed to use for creating temporary spill files at each segment. The default value is 0, which means a limit is not enforced. ============== ======== ========================== Value Range Default Set Classifications ============== ======== ========================== kilobytes 0 master, session, reload ============== ======== ========================== gp_workfile_limit_per_segment ------------------------------ Sets the maximum total disk size that all running queries are allowed to use for creating temporary spill files at each segment. The default value is 0, which means a limit is not enforced. ============== ======== ========================== Value Range Default Set Classifications ============== ======== ========================== kilobytes 0 local, system, restart ============== ======== ========================== ha_zookeeper_quorum ------------------- zookeeper server hostlist. ============ ============== ======================== Value Range Default Set Classifications ============ ============== ======================== String localhost:2181 master, session , reload ============ ============== ======================== hawq_auto_ha_timeout -------------------- Sets auto HA timeout value in millisecond. =================== ========= ======================= Value Range Default Set Classifications =================== ========= ======================= integer(1~43200000) 60000 master, session, reload =================== ========= ======================= hawq_dfs_url -------------- URL for OushuDB data directories on HDFS. The directory that you specify must be writeable by the oushu user. For example 'localhost:9000/oushu/oushudb/default_filespace’. If you have high availability enabled for your HDFS NameNodes, then this configuration parameter must be set to the service ID you configured in HDFS. See “OushuDB Filespaces and High Availability Enabled HDFS” for more information. ================================ ============================== ========================== Value Range Default Set Classifications ================================ ============================== ========================== URL in the form of NameNode_host localhost:9000/oushu/oushudb/ name:port/data_directory_name default_filespace master, session, reload ================================ ============================== ========================== hawq_global_rm_type -------------------- OushuDB global resource manager type. Valid values are yarn and none. Setting this parameter to none indicates that the OushuDB resource manager will manages its own resources. Setting the value to yarn means that OushuDB will negotiate with YARN for resources. ============== ======== ========================== Value Range Default Set Classifications ============== ======== ========================== yarn or none none master, system, restart ============== ======== ========================== hawq_hashjoin_bloomfilter ------------------------- Use bloomfilter in hash join；Use bloomfilter may speed up hash join performance. ============= ======= ======================= Value Range Default Set Classifications ============= ======= ======================= Boolean false master, session, reload ============= ======= ======================= hawq_hashjoin_bloomfilter_max_memory_size ------------------------------------------ The maximum memory size for bloom filter in hash join, with KB or MB. ============ ========= ======================== Value Range Default Set Classifications ============ ========= ======================== String 2MB master, session , reload ============ ========= ======================== hawq_hashjoin_bloomfilter_ratio ------------------------------- Sets the ratio for hash join bloom filter. ================== ========= ======================= Value Range Default Set Classifications ================== ========= ======================= float point<=1.0 0.4 master, session, reload ================== ========= ======================= hawq_hashjoin_bloomfilter_sampling_number ----------------------------------------- Sets the sampling number for hash join bloomfilter when scan the outer table. ================== ========= ======================= Value Range Default Set Classifications ================== ========= ======================= integer(100~65535) 10000 master, session, reload ================== ========= ======================= hawq_init_with_hdfs ------------------- Set if initialise cluster with Hdfs together. ============= ======= ======================= Value Range Default Set Classifications ============= ======= ======================= Boolean true master, session, reload ============= ======= ======================= hawq_master_address_host ------------------------- Address or hostname of OushuDB master. =============== ========= ========================== Value Range Default Set Classifications =============== ========= ========================== master hostname localhost master, session, reload =============== ========= ========================== hawq_master_address_port ------------------------- Port of the OushuDB master. ================= ========= ========================== Value Range Default Set Classifications ================= ========= ========================== valid port number master, session, reload ================= ========= ========================== hawq_master_directory ---------------------- Master server data directory. ================= ========= ========================== Value Range Default Set Classifications ================= ========= ========================== directory name master, session, reload ================= ========= ========================== hawq_master_temp_directory --------------------------- One or more temporary directories for the OushuDB master. Separate multiple entries with commas. ================================== ========= ========================== Value Range Default Set Classifications ================================== ========= ========================== directory name or comma-separated list of directory names /tmp master, session, reload ================================== ========= ========================== hawq_re_memory_overcommit_max ------------------------------ Sets the maximum quota of memory overcommit (in MB) per physical segment for resource enforcement. This parameter sets the memory quota that can be overcommited beyond the memory quota dynamically assigned by the resource manager. Specify a larger value to prevent out of memory errors in YARN mode. ============== ======== ========================== Value Range Default Set Classifications ============== ======== ========================== integer 8192 master, system, restart ============== ======== ========================== hawq_rm_master_port -------------------- OushuDB resource manager master port number. ================= ======== ========================== Value Range Default Set Classifications ================= ======== ========================== valid port number 5437 master, session, reload ================= ======== ========================== hawq_rm_memory_limit_perseg --------------------------- Limit of memory usage by a OushuDB segment when hawq_global_rm_type is set to none. For example, 8GB. ================================ ======== ========================== Value Range Default Set Classifications ================================ ======== ========================== no specific lower or upper limit 64GB session, reload ================================ ======== ========================== hawq_rm_nslice_perseg_limit ---------------------------- Limits the total number of slices in one OushuDB segment. OushuDB QE execution generates multiple processes called slices to process data in parallel. Too many processes can affect OS performance. If you need to allow more processes in one segment to run in parallel for high concurrency due to high complexity, then you can modify this parameter. ================= ======== ========================== Value Range Default Set Classifications ================= ======== ========================== 1 to 65535 5000 master, session, reload ================= ======== ========================== hawq_rm_segment_port --------------------- OushuDB resource manager segment server port number. ================= ======== ========================== Value Range Default Set Classifications ================= ======== ========================== valid port number 5438 master, session, reload ================= ======== ========================== enforce_nvseg ------------------- Defines the number of virtual segments to use for the next query’s execution. The default value is 0 which means statement level resource quota setting is disabled. ================= ======== ========================== Value Range Default Set Classifications ================= ======== ========================== 0 to 65535 0 master, session, reload ================= ======== ========================== hawq_segment_address_port -------------------------- Base port for the OushuDB segment host. ======================== ======== ========================== Value Range Default Set Classifications ======================== ======== ========================== valid port number local, session, reload ======================== ======== ========================== hawq_segment_directory ------------------------ Base path for the OushuDB segment data directory. ======================== ======== ========================== Value Range Default Set Classifications ======================== ======== ========================== directory name local, session, reload ======================== ======== ========================== hawq_segment_temp_directory One or more temporary directories for the OushuDB segment. Separate multiple entries with commas. ================================= ======== ========================== Value Range Default Set Classifications ================================= ======== ========================== directory name or comma-separated list of directory names /tmp local, session, reload ================================= ======== ========================== integer_datetimes ------------------ Reports whether PostgreSQL was built with support for 64-bit-integer dates and times. ============== ======== ========================== Value Range Default Set Classifications ============== ======== ========================== Booleanon on read only ============== ======== ========================== IntervalStyle ------------- Sets the display format for interval values. The value sql_standard produces output matching SQL standard interval literals. The value postgres produces output matching PostgreSQL releases prior to 8.4 when the DateStyle parameter was set to ISO. The value iso_8601 will produce output matching the time interval format with designators defined in section 4.4.3.2 of ISO 8601. See the PostgreSQL 8.4 documentation for more information. ================ ======== ========================= Value Range Default Set Classifications ================ ======== ========================= postgres postgres_verbose postgres master, session, reload sql_standard iso_8601 ================ ======== ========================= join_collapse_limit -------------------- The query optimizer (planner) will rewrite explicit inner JOIN constructs into lists of FROM items whenever a list of no more than this many items in total would result. By default, this variable is set the same as from_collapse_limit, which is appropriate for most uses. Setting it to 1 prevents any reordering of inner JOINs. Setting this variable to a value between 1 and from_collapse_limit might be useful to trade off planning time against the quality of the chosen plan (higher values produce better plans). ============== ======== ========================== Value Range Default Set Classifications ============== ======== ========================== integer (1-n) 20 master, session, reload ============== ======== ========================== krb_caseins_users ------------------ Sets whether Kerberos user names should be treated case-insensitively. The default is case sensitive (off). ============== ======== ========================== Value Range Default Set Classifications ============== ======== ========================== Boolean off master, system, restart ============== ======== ========================== krb_server_keyfile ------------------- Sets the location of the Kerberos server key file. ================== ======== ========================== Value Range Default Set Classifications ================== ======== ========================== path and file name unset master, system, restart ================== ======== ========================== krb_srvname ------------ Sets the Kerberos service name. ================== ======== ========================== Value Range Default Set Classifications ================== ======== ========================== service name postgres master, system, restart ================== ======== ========================== lc_collate ----------- Reports the locale in which sorting of textual data is done. The value is determined when the OushuDB array is initialized. ================== ======== ========================== Value Range Default Set Classifications ================== ======== ========================== postgres read only ================== ======== ========================== lc_ctype --------- Reports the locale that determines character classifications. The value is determined when the OushuDB array is initialized. ================== ======== ========================== Value Range Default Set Classifications ================== ======== ========================== read only ================== ======== ========================== lc_messages ------------ Sets the language in which messages are displayed. The locales available depends on what was installed with your operating system - use locale -a to list available locales. The default value is inherited from the execution environment of the server. On some systems, this locale category does not exist. Setting this variable will still work, but there will be no effect. Also, there is a chance that no translated messages for the desired language exist. In that case you will continue to see the English messages. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - - - local, system, restart lc_monetary ------------ Sets the locale to use for formatting monetary amounts, for example with the to_char family of functions. The locales available depends on what was installed with your operating system - use locale -a to list available locales. The default value is inherited from the execution environment of the server. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - - - local, system, restart lc_numeric ----------- Sets the locale to use for formatting numbers, for example with the to_char family of functions. The locales available depends on what was installed with your operating system - use locale -a to list available locales. The default value is inherited from the execution environment of the server. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - - - local, system, restart lc_time -------- This parameter currently does nothing, but may in the future. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - - - local, system, restart listen_addresses ----------------- Specifies the TCP/IP address(es) on which the server is to listen for connections from client applications - a comma-separated list of host names and/or numeric IP addresses. The special entry * corresponds to all available IP interfaces. If the list is empty, only UNIX-domain sockets can connect. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - localhost,host names,IP addresses,* (all available IP interfaces) - - master, system, restart local_preload_libraries ------------------------ Comma separated list of shared library files to preload at the start of a client session. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - String (comma-separated list) - no value set - local, system, restart .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - Boolean - off - master, session, reload, superuser log_connections ---------------- This outputs a line to the server log detailing each successful connection. Some client programs, like psql, attempt to connect twice while determining if a password is required, so duplicate “connection received” messages do not always indicate a problem. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - Boolean - off - local, system, restart log_disconnections ------------------- This outputs a line in the server log at termination of a client session, and includes the duration of the session. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - Boolean - off - local, system, restart log_dispatch_stats -------------------- When set to “on,” this parameter adds a log message with verbose information about the dispatch of the statement. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - Boolean - off - local, system, restart log_duration ------------- Causes the duration of every completed statement which satisfies log_statement to be logged. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - Boolean - off - master, session, reload, superuser log_error_verbosity -------------------- Controls the amount of detail written in the server log for each message that is logged. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - TERSE DEFAULT VERBOSE - off - master, session, reload, superuser log_executor_stats ------------------- For each query, write performance statistics of the query executor to the server log. This is a crude profiling instrument. Cannot be enabled together with log_statement_stats. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - Boolean - off - local, system, restart log_hostname ------------- By default, connection log messages only show the IP address of the connecting host. Turning on this option causes logging of the IP address and host name of the OushuDB master. Note that depending on your host name resolution setup this might impose a non-negligible performance penalty. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - Boolean - off - master, system, restart log_min_duration_statement ---------------------------- Logs the statement and its duration on a single log line if its duration is greater than or equal to the specified number of milliseconds. Setting this to 0 will print all statements and their durations. -1 disables the feature. For example, if you set it to 250 then all SQL statements that run 250ms or longer will be logged. Enabling this option can be useful in tracking down unoptimized queries in your applications. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - number of milliseconds, 0, -1 - -1 - master, session, reload, superuser log_min_error_statement ----------------------- Controls whether or not the SQL statement that causes an error condition will also be recorded in the server log. All SQL statements that cause an error of the specified level or higher are logged. The default is PANIC (effectively turning this feature off for normal use). Enabling this option can be helpful in tracking down the source of any errors that appear in the server log. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - DEBUG5 DEBUG4 DEBUG3 DEBUG2 DEBUG1 INFO NOTICE WARNING ERROR FATAL PANIC - ERROR - master, session, reload, superuser log_min_messages ----------------- Controls which message levels are written to the server log. Each level includes all the levels that follow it. The later the level, the fewer messages are sent to the log. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - DEBUG5 DEBUG4 DEBUG3 DEBUG2 DEBUG1 INFO NOTICE WARNING ERROR FATAL PANIC - WARNING - master, session, reload, superuser log_parser_stats ---------------- For each query, write performance statistics of the query parser to the server log. This is a crude profiling instrument. Cannot be enabled together with log_statement_stats. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - Boolean - off - master, session, reload, superuser log_planner_stats ----------------- For each query, write performance statistics of the legacy query optimizer (planner) to the server log. This is a crude profiling instrument. Cannot be enabled together with log_statement_stats. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - Boolean - off - master, session, reload, superuser log_rotation_age ----------------- Determines the maximum lifetime of an individual log file. After this time has elapsed, a new log file will be created. Set to zero to disable time-based creation of new log files. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - Any valid time expression (number and unit) - 1d - local, system, restart log_rotation_size ------------------ Determines the maximum size of an individual log file. After this many kilobytes have been emitted into a log file, a new log file will be created. Set to zero to disable size-based creation of new log files. The maximum value is INT_MAX/1024. If an invalid value is specified, the default value is used. INT_MAX is the largest value that can be stored as an integer on your system. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - number of kilobytes - 0 - local, system, restart log_statement -------------- Controls which SQL statements are logged. DDL logs all data definition commands like CREATE, ALTER, and DROP commands. MOD logs all DDL statements, plus INSERT, TRUNCATE, and COPY FROM. PREPARE and EXPLAIN ANALYZE statements are also logged if their contained command is of an appropriate type. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - NONE DDL MOD ALL - ALL - master, session, reload, superuser log_statement_stats -------------------- For each query, write total performance statistics of the query parser, planner, and executor to the server log. This is a crude profiling instrument. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - Boolean - unknown - local, system, restart log_timezone ------------- Sets the time zone used for timestamps written in the log. Unlike TimeZone, this value is system-wide, so that all sessions will report timestamps consistently. The default is unknown, which means to use whatever the system environment specifies as the time zone. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - String - unknown - local, system, restart log_truncate_on_rotation ------------------------- Truncates (overwrites), rather than appends to, any existing log file of the same name. Truncation will occur only when a new file is being opened due to time-based rotation. For example, using this setting in combination with a log_filename such as hawq-%H.log would result in generating twenty-four hourly log files and then cyclically overwriting them. When off, pre-existing files will be appended to in all cases. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - Boolean - off - local, system, restart maintenance_work_mem --------------------- Sets the maximum amount of memory to be used for maintenance operations including vacuum and create index. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - 1024KB - (no upper bound) - 65536KB - master, session, reload magma_nodes_url --------------- Sets the urls for accessing magma. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - String - localhost:6666 - master, session, reload max_appendonly_tables ----------------------- Sets the maximum number of append-only relations that can be written to or loaded concurrently. Append-only table partitions and subpartitions are considered as unique tables against this limit. Increasing the limit will allocate more shared memory at server start. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - integer - 10000 - master, system, restart max_connections ---------------- The maximum number of concurrent connections allowed on master. In a OushuDB system, user client connections go through the OushuDB master instance only. Segment instances should allow 5-10 times the amount as the master. When you increase this parameter, you must increase max_prepared_transactions as well. For more information about limiting concurrent connections, see Configuring Client Authentication. Increasing this parameter may cause OushuDB to request more shared memory. See shared_buffers for information about OushuDB server instance shared memory buffers. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - integer (10-n) - 1280 - local, system, restart max_files_per_process ---------------------- Sets the maximum number of simultaneously open files allowed to each server subprocess. If the kernel is enforcing a safe per-process limit, you don’t need to worry about this setting. Some platforms such as BSD, the kernel will allow individual processes to open many more files than the system can really support. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - integer (40-n) - 150 - local, system, restart max_fsm_pages -------------- Sets the maximum number of disk pages for which free space will be tracked in the shared free-space map. Six bytes of shared memory are consumed for each page slot. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - integer > 16 * max_fsm_relations - 200000 - local, system, restart max_fsm_relations ------------------ Sets the maximum number of relations for which free space will be tracked in the shared memory free-space map. Should be set to a value larger than the total number of: tables + indexes + system tables. It costs about 60 bytes of memory for each relation per segment instance. It is better to allow some room for overhead and set too high rather than too low. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - integer - 1000 - local, system, restart max_function_args ------------------ Reports the maximum number of function arguments. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - integer - 100 - read only max_identifier_length ---------------------- Reports the maximum identifier length. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - integer - 63 - read only max_index_keys --------------- Reports the maximum number of index keys. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - integer - 32 - read only max_locks_per_transaction -------------------------- The shared lock table is created with room to describe locks on max_locks_per_transaction * (max_connections + max_prepared_transactions) objects, so no more than this many distinct objects can be locked at any one time. This is not a hard limit on the number of locks taken by any one transaction, but rather a maximum average value. You might need to raise this value if you have clients that touch many different tables in a single transaction. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - integer - 128 - local, system, restart max_prepared_transactions -------------------------- Sets the maximum number of transactions that can be in the prepared state simultaneously. OushuDB uses prepared transactions internally to ensure data integrity across the segments. This value must be at least as large as the value of max_connections on the master. Segment instances should be set to the same value as the master. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - integer - 250 on master, 250 on segments - local, system, restart max_stack_depth ---------------- Specifies the maximum safe depth of the server’s execution stack. The ideal setting for this parameter is the actual stack size limit enforced by the kernel (as set by ulimit -s or local equivalent), less a safety margin of a megabyte or so. Setting the parameter higher than the actual kernel limit will mean that a runaway recursive function can crash an individual backend process. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - number of kilobytes - 2MB - local, system, restart new_executor ------------- Enable new executor. The default is auto, which means try new executor first, then fall back to old executor. ============= ======== ========================== Value Range Default Set Classifications ============= ======== ========================== String AUTO master, session , reload ============= ======== ========================== new_executor_enable_external_sort --------------------------------- Enable the new executor's external sort.Valid values are "OFF", "AUTO" and "ON". ================== ========= ======================== Value Range Default Set Classifications ================== ========= ======================== String OFF master, session , reload ================== ========= ======================== new_executor_enable_partitioned_hashagg ---------------------------------------- Enable the new executor's partitioned hash aggregation.Valid values are "OFF", "AUTO" and "ON". ================== ========= ======================== Value Range Default Set Classifications ================== ========= ======================== String AUTO master, session , reload ================== ========= ======================== new_executor_enable_partitioned_hashjoin ---------------------------------------- Enable the new executor's partitioned hash join.Valid values are "OFF", "AUTO" and "ON". ================== ========= ======================== Value Range Default Set Classifications ================== ========= ======================== String AUTO master, session , reload ================== ========= ======================== new_executor_ic_tcp_client_limit_per_query_per_segment ------------------------------------------------------ Set new_executor_ic_tcp_client_limit_per_query_per_segment. ================ ======= ======================= Value Range Default Set Classifications ================ ======= ======================= integer(0~65535) 10000 master, session, reload ================ ======= ======================= new_executor_partitioned_hash_recursive_depth_limit --------------------------------------------------- Set new_executor_partitioned_hash_recursive_depth_limit. ============= ======= ======================= Value Range Default Set Classifications ============= ======= ======================= integer(0~10) 6 master, session, reload ============= ======= ======================= new_executor_runtime_filter_mode -------------------------------- Enable the new executor's runtime filter.Valid values are "OFF", "AUTO" and "ON". ================== ========= ======================== Value Range Default Set Classifications ================== ========= ======================== String OFF master, session , reload ================== ========= ======================== new_interconnect_type --------------------- Sets the protocol used for inter-node communication for new executor.Valid values are \"tcp\" and \"udp\". ================== ========= ======================= Value Range Default Set Classifications ================== ========= ======================= String UDP local, system, restart ================== ========= ======================= optimizer ---------- Enables the GPORCA when running SQL queries. The default is on. When off, OushuDB uses only the legacy query optimizer. GPORCA co-exists with the legacy query optimizer. When GPORCA is enabled, OushuDB uses GPORCA to generate an execution plan for a query when possible. If GPORCA cannot be used, the legacy query optimizer is used. The optimizer parameter can be set for a database system, an individual database, or a session or query. For information about the legacy query optimizer and GPORCA, see About GPORCA. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - Boolean - on - master, session, reload optimizer_analyze_root_partition --------------------------------- For a partitioned table, collects statistics for the root partition when the ANALYZE command is run on the table. GPORCA uses the root partition statistics when generating a query plan. The legacy query optimizer does not use these statistics. If you set the value of the server configuration parameter optimizer to on, set the value of this parameter to on and run the command ANALYZE or ANALYZE ROOTPARTITION on partitioned tables to ensure the proper statistics have been collected. For information about the legacy query optimizer and GPORCA, see About GPORCA. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - Boolean - on - master, session, reload optimizer_minidump ------------------- GPORCA generates minidump files to describe the optimization context for a given query. Use the minidump files to analyze OushuDB issues. The minidump file is located under the master data directory and uses the following naming format: Minidump_date_time.mdp The minidump file contains this query related information: * Catalog objects including data types, tables, operators, and statistics required by GPORCA * An internal representation (DXL) of the query * An internal representation (DXL) of the plan produced by GPORCA * System configuration information passed to GPORCA such as server configuration parameters, cost and statistics configuration, and number of segments * A stack trace of errors generated while optimizing the query Setting this parameter to ALWAYS generates a minidump for all queries. Note: Set this parameter to ONERROR in production environments to minimize total optimization time. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - ONERROR ALWAYS - ONERROR - master, session, reload optimizer_parts_to_force_sort_on_insert ---------------------------------------- Sets the minimum number of partitions required to force GPORCA to generate a plan for sorting tuples during insertion into an append-only, row-oriented (AORO) partitioned tables. If the number of partitions is less than the specified value, no sorting is performed. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - integer - 160 - master, session, reload optimizer_prefer_scalar_dqa_multistage_agg ------------------------------------------- When enabled, this parameter forces the GPORCA to use a three-stage scalar DQA plan. This type of plan evaluates the aggregate functions in three stages (local, intermediate, and global aggregations). By forcing the use of this plan, GPORCA ensures predictable performance for queries that contain distinct qualified aggregates (DQA). By default, this configuration is on. If you set this parameter to false, then GPORCA makes a cost-based decision. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - Boolean - true (on) - master, session, reload password_encryption -------------------- When a password is specified in CREATE USER or ALTER USER without writing either ENCRYPTED or UNENCRYPTED, this option determines whether the password is to be encrypted. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - Boolean - on - master, session, reload password_hash_algorithm ------------------------ Specifies the cryptographic hash algorithm that is used when storing an encrypted OushuDB Database user password. The default algorithm is MD5. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - MD5

SHA-256 - MD5 - master, session, reload, superuser pgstat_track_activity_query_size --------------------------------- Sets the maximum length limit for the query text stored in current_query column of the system catalog view pg_stat_activity. The minimum length is 1024 characters. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - integer - 1024 - local, system, restart pljava_classpath ------------------ A colon (:) separated list of the jar files containing the Java classes used in any PL/Java functions. The jar files listed here must also be installed on all OushuDB hosts in the following location: $GPHOME/lib/postgresql/java/ .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - String - - master, session, reload pljava_release_lingering_savepoints ------------------------------------ If true, lingering savepoints used in PL/Java functions will be released on function exit. If false, savepoints will be rolled back. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - Boolean - true - master, system, restart, superuser pljava_statement_cache_size ---------------------------- Sets the size in KB of the JRE MRU (Most Recently Used) cache for prepared statements. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - number of kilobytes - 10 - master, system, restart, superuser pljava_vmoptions ----------------- Defines the startup options for the Java VM. The default value is an empty string (“”). .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - String - - master, system, restart, superuser port ----- The database listener port for a OushuDB instance. The master and each segment has its own port. Port numbers for the OushuDB system must also be changed in the gp_segment_configuration catalog. You must shut down your OushuDB system before changing port numbers. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - any valid port number - 5432 - local, system, restart random_page_cost ----------------- Sets the estimate of the cost of a nonsequentially fetched disk page for the legacy query optimizer (planner). This is measured as a multiple of the cost of a sequential page fetch. A higher value makes it more likely a sequential scan will be used, a lower value makes it more likely an index scan will be used. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - floating point - 100 - master, session, reload readable_external_table_timeout ------------------------------- Cancel the query if no data read within N seconds.A value of 0 turns off the timeout. ================ ========= ======================= Value Range Default Set Classifications ================ ========= ======================= integer(0~65535) 0 master, session, reload ================ ========= ======================= regex_flavor ------------- The 'extended’ setting may be useful for exact backwards compatibility with pre-7.4 releases of PostgreSQL. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - advanced extended basic - advanced - master, session, reload runaway_detector_activation_percent ------------------------------------ Sets the percentage of the virtual memory quota that will trigger the termination of queries. If the amount of virtual memory utilized by a physical segment exceeds the calculated threshold, then OushuDB begins terminating queries based on memory usage, starting with the query that is consuming the largest amount of memory. Queries are terminated until the percentage of utilized virtual memory is below the specified percentage. The amount of virtual memory available to a physical segment is calculated dynamically in OushuDB. OushuDB’s resource manager determines resource allocations and quotas based on resources available to the cluster, resource queue configuration and other deployment configuration factors. To calculate the memory usage threshold for runaway queries, OushuDB uses the following formula: vmem threshold = (virtual memory quota calculated by resource manager + hawq_re_memory_overcommit_max) * runaway_detector_activation_percent. For example, if OushuDB resource manager calculates a virtual memory quota of 9GB,hawq_re_memory_overcommit_max is set to 1GB and the value of runaway_detector_activation_percent is 95 (95%), then OushuDB starts terminating queries when the utilized virtual memory exceeds 9.5 GB. A value of 100 disables the automatic detection and termination of runaway queries. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - 0 to 100 - 95 - master, session, reload search_path ------------ Specifies the order in which schemas are searched when an object is referenced by a simple name with no schema component. When there are objects of identical names in different schemas, the one found first in the search path is used. The system catalog schema, pg_catalog, is always searched, whether it is mentioned in the path or not. When objects are created without specifying a particular target schema, they will be placed in the first schema listed in the search path. The current effective value of the search path can be examined via the SQL function current_schemas(). current_schemas() shows how the requests appearing in search_path were resolved. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - a comma-separated list of schema names - $user,public - master, session, reload seg_max_connections -------------------- The maximum number of concurrent connections on a segment. In a OushuDB system, user client connections go through the OushuDB master instance only. Segment instances should allow 5-10 times the amount of connections allowed on the master (see max_connections.) When you increase this parameter, you must increase max_prepared_transactions as well. For more information about limiting concurrent connections, see Configuring Client Authentication. Increasing this parameter may cause OushuDB to request more shared memory. See shared_buffers for information about OushuDB server instance shared memory buffers. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - integer (240-n) - 1280 - local, system, restart seq_page_cost -------------- For the legacy query optimizer (planner), sets the estimate of the cost of a disk page fetch that is part of a series of sequential fetches. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - floating point - 1 - master, session, reload server_encoding ---------------- Reports the database encoding (character set). It is determined when the OushuDB array is initialized. Ordinarily, clients need only be concerned with the value of client_encoding. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - - UTF8 - read only server_version --------------- Reports the version of PostgreSQL that this release of OushuDB is based on. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - String - 8.2.15 - read only server_version_num ------------------- Reports the version of PostgreSQL that this release of OushuDB is based on as an integer. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - integer - 80215 - read only share_input_scan_wait_lockfile_timeout -------------------------------------- timeout (in millisecond) for waiting lock file which writer creates. ============= ========= ======================= Value Range Default Set Classifications ============= ========= ======================= integer(>=1) 300000 master, session, reload ============= ========= ======================= shared_buffers ---------------- Sets the amount of memory a OushuDB segment instance uses for shared memory buffers. This setting must be at least 128KB and at least 16KB times max_connections. Each OushuDB segment instance calculates and attempts to allocate certain amount of shared memory based on the segment configuration. The value of shared_buffers is significant portion of this shared memory calculation, but is not all it. When setting shared_buffers, the values for the operating system parameters SHMMAX or SHMALL might also need to be adjusted. The operating system parameter SHMMAX specifies maximum size of a single shared memory allocation. The value of SHMMAX must be greater than this value: .. code-block:: html :linenos: shared_buffers + other_seg_shmem The value of other_seg_shmem is the portion the OushuDB shared memory calculation that is not accounted for by the shared_buffers value. The other_seg_shmem value will vary based on the segment configuration. With the default OushuDB parameter values, the value for other_seg_shmem is approximately 111MB for OushuDB segments and approximately 79MB for the OushuDB master. The operating system parameter SHMALL specifies the maximum amount of shared memory on the host. The value of SHMALL must be greater than this value: .. code-block:: html :linenos: (num_instances_per_host * ( shared_buffers + other_seg_shmem )) + other_app_shared_mem The value of other_app_shared_mem is the amount of shared memory that is used by other applications and processes on the host. When shared memory allocation errors occur, possible ways to resolve shared memory allocation issues are to increase SHMMAX or SHMALL, or decrease shared_buffers or max_connections. See OushuDB installation documentation for information about the OushuDB values for the parameters SHMMAX and SHMALL. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - integer > 16K * max_connections - 125MB - segment, system, restart shared_preload_libraries -------------------------- A comma-separated list of shared libraries that are to be preloaded at server start. PostgreSQL procedural language libraries can be preloaded in this way, typically by using the syntax ’$libdir/plXXX’ where XXX is pgsql, perl, tcl, or python. By preloading a shared library, the library startup time is avoided when the library is first used. If a specified library is not found, the server will fail to start. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - String (comma-separated list) - no value set - local, system, restart ssl ---- Enables SSL connections. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - Boolean - off - master, system, restart ssl_ciphers ------------ Specifies a list of SSL ciphers that are allowed to be used on secure connections. See the openssl manual page for a list of supported ciphers. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - String - ALL - master, system, restart standard_conforming_strings ---------------------------- Reports whether ordinary string literals (’…’) treat backslashes literally, as specified in the SQL standard. The value is currently always off, indicating that backslashes are treated as escapes. It is planned that this will change to on in a future release when string literal syntax changes to meet the standard. Applications may check this parameter to determine how string literals will be processed. The presence of this parameter can also be taken as an indication that the escape string syntax (E’…’) is supported. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - Boolean - off - read only statement_timeout ----------------- Abort any statement that takes over the specified number of milliseconds. 0 turns off the limitation. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - number of milliseconds - 0 - master, session, reload superuser_reserved_connections ------------------------------- Determines the number of connection slots that are reserved for OushuDB superusers. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - integer < max_connections - 3 - local, system, restart tcp_keepalives_count --------------------- How many keepalives may be lost before the connection is considered dead. A value of 0 uses the system default. If TCP_KEEPCNT is not supported, this parameter must be 0. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - number of lost keepalives - 0 - local, system, restart tcp_keepalives_idle ------------------- Number of seconds between sending keepalives on an otherwise idle connection. A value of 0 uses the system default. If TCP_KEEPIDLE is not supported, this parameter must be 0. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - number of lost keepalives - 0 - local, system, restart tcp_keepalives_interval ------------------------ How many seconds to wait for a response to a keepalive before retransmitting. A value of 0 uses the system default. If TCP_KEEPINTVL is not supported, this parameter must be 0. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - number of lost keepalives - 0 - local, system, restart temp_buffers ------------- Sets the maximum number of temporary buffers used by each database session. These are session-local buffers used only for access to temporary tables. The setting can be changed within individual sessions, but only up until the first use of temporary tables within a session. The cost of setting a large value in sessions that do not actually need a lot of temporary buffers is only a buffer descriptor, or about 64 bytes, per increment. However if a buffer is actually used, an additional 8192 bytes will be consumed. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - integer - 1024 - master, session, reload TimeZone --------- Sets the time zone for displaying and interpreting time stamps. The default is to use whatever the system environment specifies as the time zone. See Date/Time Keywords in the PostgreSQL documentation. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - time zone abbreviation - - local, restart timezone_abbreviations ----------------------- Sets the collection of time zone abbreviations that will be accepted by the server for date time input. The default is Default, which is a collection that works in most of the world. Australia and India, and other collections can be defined for a particular installation. Possible values are names of configuration files stored in $GPHOME/share/postgresql/timezonesets/. To configure OushuDB to use a custom collection of timezones, copy the file that contains the timezone definitions to the directory $GPHOME/share/postgresql/timezonesets/ on the OushuDB master and segment hosts. Then set value of the server configuration parameter timezone_abbreviations to the file. For example, to use a file custom that contains the default timezones and the WIB (Waktu Indonesia Barat) timezone. #. Copy the file Default from the directory $GPHOME/share/postgresql/timezonesets/ the file custom. Add the WIB timezone information from the file Asia.txt to the custom. #. Copy the file custom to the directory $GPHOME/share/postgresql/timezonesets/ on the OushuDB master and segment hosts. #. Set value of the server configuration parameter timezone_abbreviations to custom. #. Reload the server configuration file (oushudb stop cluster -u). track_activities ----------------- Enables the collection of statistics on the currently executing command of each session, along with the time at which that command began execution. When enabled, this information is not visible to all users, only to superusers and the user owning the session. This data can be accessed via the pg_stat_activity system view. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - Boolean - on - master, session, reload track_counts ------------- Enables the collection of row and block level statistics on database activity. If enabled, the data that is produced can be accessed via the pg_stat and pg_statio family of system views. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - Boolean - off - local, system, restart transaction_isolation ---------------------- Sets the current transaction’s isolation level. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - read committed serializable - read committed - master, session, reload transaction_read_only ---------------------- Sets the current transaction’s read-only status. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - Boolean - off - master, session, reload transform_null_equals ---------------------- When on, expressions of the form expr = NULL (or NULL = expr) are treated as expr IS NULL, that is, they return true if expr evaluates to the null value, and false otherwise. The correct SQL-spec-compliant behavior of expr = NULL is to always return null (unknown). .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - Boolean - off - master, session, reload unix_socket_directory --------------------- Specifies the directory of the UNIX-domain socket on which the server is to listen for connections from client applications. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - directory path - unset - local, system, restart unix_socket_group ------------------ Sets the owning group of the UNIX-domain socket. By default this is an empty string, which uses the default group for the current user. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - UNIX group name - unset - local, system, restart unix_socket_permissions ------------------------ Sets the access permissions of the UNIX-domain socket. UNIX-domain sockets use the usual UNIX file system permission set. Note that for a UNIX-domain socket, only write permission matters. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - numeric UNIX file permission mode (as accepted by the chmod or umask commands) - 511 - local, system, restart update_process_title ---------------------- Enables updating of the process title every time a new SQL command is received by the server. The process title is typically viewed by the ps command. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - Boolean - on - local, system, restart vacuum_cost_delay ------------------ The length of time that the process will sleep when the cost limit has been exceeded. 0 disables the cost-based vacuum delay feature. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - milliseconds < 0 (in multiples of 10) - 0 - local, system, restart vacuum_cost_limit ------------------ The accumulated cost that will cause the vacuuming process to sleep. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - integer > 0 - 200 - local, system, restart vacuum_cost_page_dirty ---------------------- The estimated cost charged when vacuum modifies a block that was previously clean. It represents the extra I/O required to flush the dirty block out to disk again. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - integer > 0 - 20 - local, system, restart vacuum_cost_page_miss ---------------------- The estimated cost for vacuuming a buffer that has to be read from disk. This represents the effort to lock the buffer pool, lookup the shared hash table, read the desired block in from the disk and scan its content. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - integer > 0 - 10 - local, system, restart vacuum_freeze_min_age ---------------------- Specifies the cutoff age (in transactions) that VACUUM should use to decide whether to replace transaction IDs with FrozenXID while scanning a table. For information about VACUUM and transaction ID management, see Managing Data with OushuDB and the PostgreSQL documentation. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - integer 0-100000000000 - 100000000 - local, system, restart writable_external_table_bufsize ------------------------------- Buffer size in kilobytes for writable external table before writing data to gpfdist.Valid value is between 32K and 128M: [32, 131072]. ================== ========= ======================= Value Range Default Set Classifications ================== ========= ======================= integer 32-131072 64 master, session, reload ================== ========= ======================= xid_stop_limit --------------- The number of transaction IDs prior to the ID where transaction ID wraparound occurs. When this limit is reached, OushuDB stops creating new transactions to avoid data loss due to transaction ID wraparound. .. list-table:: :widths: auto :header-rows: 1 :align: left * - Value Range - Default - Set Classifications * - integer 0-100000000000 - 20000000 - local, system, restart