System Performance Snapshot

enable_wdr_snapshot

Parameter description: Specifies whether to enable the database monitoring snapshot function.

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

Value range: Boolean

• on indicates that the database monitoring snapshot function is enabled.
• off indicates that the database monitoring snapshot function is disabled.

Default value: off

wdr_snapshot_retention_days

Parameter description: Specifies the number of days for storing database monitoring snapshot data in the system. When the number of snapshots generated during database running exceeds the maximum number of snapshots that can be generated within the retention period, the system clears the snapshot data with the smallest snapshot_id at the interval specified by wdr_snapshot_interval.

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

Value range: an integer ranging from 1 to 8

Default value: 8

wdr_snapshot_query_timeout

Parameter description: Specifies the execution timeout for the SQL statements associated with database monitoring snapshot operations. If the SQL statement execution is not complete and a result is not returned within the specified time, the snapshot operation fails.

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

Value range: an integer ranging from 100 to INT_MAX. The unit is s.

Default value: 100s

wdr_snapshot_interval

Parameter description: Specifies the interval at which the background thread Snapshot automatically performs snapshot operations on the database monitoring data.

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

Value range: an integer ranging from 10 to 60. The unit is m.

Default value: 1h

asp_flush_mode

Parameter description: Specifies the mode for the ASP to update data to the disk. The value can be file (default value), table (system catalog), or all (system catalog and file). Only the sysadmin user can access this parameter.

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

Value range: a string, which can be table, file, or all

Default value: table

asp_flush_rate

Parameter description: When the number of samples reaches the value of asp_sample_num, the samples in the memory are updated to the disk based on a certain proportion. asp_flush_rate indicates the update proportion. If this parameter is set to 10, it indicates that the update ratio is 10:1.

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

Value range: an integer ranging from 1 to 10

Default value: 10

asp_log_filename

Parameter description: Specifies the file name format when writing files using ASP. Only the sysadmin user can access this parameter.

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

Value range: a string

Default value: asp-%Y-%m-%d_%H%M%S.log

asp_retention_days

Parameter description: Specifies the maximum number of days for reserving ASP samples when they are written to the system catalog.

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

Value range: an integer ranging from 1 to 7

Default value: 2

asp_sample_interval

Parameter description: Specifies the sampling interval.

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

Value range: an integer ranging from 1 to 10. The unit is s.

Default value: 1s

asp_sample_num

Parameter description: Specifies the maximum number of samples allowed in the LOCAL_ACTIVE_SESSION view. Only the sysadmin user can access this parameter.

This parameter is a POSTMASTER parameter. Set it based on instructions provided in Table 1 GUC parameters.

Value range: an integer ranging from 10 to 100000

Default value: 100000

enable_asp

**Parameter description:**Specifies whether to enable the active session profile function.

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

Value range: Boolean

• on: The function is enabled.
• off: The function is disabled.

Default value: on