Query and Index Statistics Collector

track_activities

Parameter description: Collects statistics about the commands that are being executed in each session. For a stored procedure, if this parameter is enabled, you can view the PERFORM statement, stored procedure calling statement, SQL statement, and OPEN CURSOR statement that are being executed in the stored procedure in the pg_stat_activity view.

This is a SUSET parameter. Set it based on instructions provided in Table 1.

Value range: Boolean

• on indicates that the statistics collection function is enabled.
• off indicates that the statistics collection function is disabled.

Default value: on

If this parameter is set to off, the memory recycling capability of the storage engine is affected, causing space expansion.

track_counts

Parameter description: Collects statistics about database activities.

This is a SUSET parameter. Set it based on instructions provided in Table 1.

Value range: Boolean

• on indicates that the statistics collection function is enabled.
• off indicates that the statistics collection function is disabled.

Database statistics are required when the autovacuum process checks for databases that need to be vacuumed. Therefore, the default value is set to on.

Default value: on

If this parameter is set to off, the memory recycling capability of the storage engine is affected, causing space expansion.

track_procedure_sql

Parameter description: Specifies whether the SQL statements that are being executed in the stored procedure are printed in the query column in the pg_stat_activity system catalog.

Parameter type: Boolean

Unit: none

Value range: on or off

• on: indicates that when a stored procedure is called, the statements that are being executed by the stored procedure are printed in the query column of pg_stat_activity.
• off: indicates that when a stored procedure is called, only statements for invoking the stored procedure are printed in the query column of pg_stat_activity.

Default value: on

Setting method: This is a USERSET parameter. Set it based on instructions provided in Table 1.

Setting suggestion: none

track_io_timing

Parameter description: Collects statistics about I/O timing in the database. The I/O timing statistics can be queried by using the pg_stat_database parameter.

This is a SUSET parameter. Set it based on instructions provided in Table 1.

Value range: Boolean

• If this parameter is set to on, the collection function is enabled. In this case, the collector repeatedly queries the OS at the current time. As a result, large number of costs may occur on some platforms. Therefore, the default value is set to off.
• off indicates that the statistics collection function is disabled.

Default value: off

track_functions

Parameter description: Collects statistics of the number and duration of function invocations.

This is a SUSET parameter. Set it based on instructions provided in Table 1.

When the SQL functions are set to inline functions queried by the invoking, these SQL functions cannot be traced no matter these functions are set or not.

Value range: enumerated values

• pl indicates that only procedural language functions are traced.
• all indicates that SQL language functions area traced.
• none indicates that the function tracing function is disabled.

Default value: none

track_activity_query_size

Parameter description: Specifies byte counts of the current running commands used to trace each active session. If the actual number of bytes in a command is greater than the value of this parameter, the command is truncated.

Parameter type: integer

Unit: byte

Value range: 100 to 102400

Default value: 1024

Setting method: This is a POSTMASTER parameter. Set it based on instructions provided in Table 1.

Setting suggestion: Set this parameter based on the actual service scenario.

update_process_title

Parameter description: Collects statistics updated with a process name each time the server receives a new SQL statement.

The process name can be viewed by running the ps command.

This is an INTERNAL parameter. Set it based on instructions provided in Table 1.

Value range: Boolean

• on indicates that the statistics collection function is enabled.
• off indicates that the statistics collection function is disabled.

Default value: off

stats_temp_directory

Parameter description: Specifies the directory for storing temporary statistics. Only the sysadmin user can access this parameter.

This is a SIGHUP parameter. Set it based on instructions provided in Table 1.

If a RAM-based file system directory is used, the actual I/O cost can be lowered and the performance can be improved.

Value range: a string

Default value: pg_stat_tmp

track_thread_wait_status_interval

Parameter description: Specifies the interval of collecting the thread status information.

This is a SUSET parameter. Set it based on instructions provided in Table 1.

Value range: 0 to 1 day. The unit is min.

Default value: 30min

enable_save_datachanged_timestamp

Parameter description: Specifies whether to record the time when INSERT, UPDATE, DELETE, or EXCHANGE/TRUNCATE/DROP PARTITION is performed on table data.

This is a USERSET parameter. Set it based on instructions provided in Table 1.

Value range: Boolean

• on indicates that the time when an operation is performed on table data will be recorded.
• off indicates that the time when an operation is performed on table data will not be recorded.

Default value: on

enable_plan_trace

Parameter description: Specifies whether to enable the PLAN TRACE feature for the database. This parameter cannot be set globally by running the gs_guc command. It can be set only by running the set command in a connected session.

This is a USERSET parameter. Set it based on instructions provided in Table 1.

Value range: Boolean

• on indicates that the PLAN TRACE feature is enabled.
• off indicates that the PLAN TRACE feature is disabled.

Default value: off

plan_collect_thresh

Parameter description: Collects statistics about the plans that are being executed in each session.

This is a SUSET parameter. Set it based on instructions provided in Table 1.

Value range: an integer ranging from –1 to 2147483647

• –1: Plans that are being executed are not collected.
• 0: Plans that are being executed are collected before plan execution.
• A value greater than 0 indicates that when the total number of tuples incrementally returned by all operators in a plan is greater than or equal to the value of this parameter, plans that are being executed are collected once.

Default value: 0

track_sql_count

Parameter description: Collects statistics about the statements (SELECT, INSERT, UPDATE, MERGE INTO, and DELETE) that are being executed in a session.

In the x86-based centralized deployment scenario, the hardware configuration specifications are 32-core CPU and 256 GB memory. When the Benchmark SQL 5.0 tool is used to test performance, the performance fluctuates by about 0.8% by enabling or disabling this parameter.

This is a SUSET parameter. Set it based on instructions provided in Table 1.

Value range: Boolean

• on indicates that the statistics collection function is enabled.
• off indicates that the statistics collection function is disabled.

Default value: on

• The track_sql_count parameter is restricted by the track_activities parameter.
  • If track_activities is set to on and track_sql_count is set to off, a warning message indicating that track_sql_count is disabled will be displayed in logs when the gs_sql_count view is queried.
  • If both track_activities and track_sql_count are set to off, two warning messages indicating that track_activities is disabled and track_sql_count is disabled will be displayed in logs when the views are queried.
  • If track_activities is set to off and track_sql_count is set to on, a warning message indicating that track_activities is disabled will be displayed in logs when the views are queried.

• If this parameter is disabled, the query result is 0.