Query

instr_unique_sql_count

Parameter description: Specifies the maximum number of Unique SQL records to be collected. The value 0 indicates that the function of collecting Unique SQL information is disabled.

If the value is changed from a larger one to a smaller one, Unique SQL statistics will be reset and re-collected. There is no impact if the value is changed from a smaller one to a larger one.

If the number of unique SQL entries generated in the system is greater than instr_unique_sql_count and the function of automatically eliminating unique SQL entries is enabled, the system automatically eliminates a certain proportion of entries based on the update time of unique SQL statements in descending order. In this way, new unique SQL entries can be collected. If the automatic elimination function is not enabled, new unique SQL information generated by the system will not be collected.

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

Value range: an integer ranging from 0 to 2147483647

Default value: 100

CAUTION:

• If the automatic elimination function is enabled and this parameter is set to a small value, the system may frequently perform automatic elimination, which may affect the database system performance. Therefore, you are advised to set this parameter to 200000.
• If automatic elimination is enabled and this parameter is set to a large value (for example, 38347922), a large memory problem may occur during the clearance. As a result, the clearance fails.

instr_unique_sql_track_type

Parameter description: Specifies which SQL statements are recorded in Unique SQL.

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

Value range: enumerated values

top: Only top-level SQL statements are recorded.

Default value: top

enable_instr_rt_percentile

Parameter description: Specifies whether to enable the function of calculating the response time of 80% and 95% SQL statements in the system.

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

Value range: Boolean

• on indicates that the function of calculating the response time of 80% and 95% SQL statements is enabled.
• off indicates that the function of calculating the response time of 80% and 95% SQL statements is disabled.

Default value: on

percentile

Parameter description: Specifies the percentage of SQL statements whose response time is to be calculated by the background calculation thread.

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

Value range: a string

Default value: 80, 95

instr_rt_percentile_interval

Parameter description: Specifies the interval at which the background calculation thread calculates the SQL response time.

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

Value range: an integer ranging from 0 to 3600. The unit is s.

Default value: 10s

enable_instr_cpu_timer

Parameter description: Specifies whether to capture the CPU time consumed during SQL statement execution.

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

Value range: Boolean

• on indicates the CPU time consumed during SQL statement execution is captured.
• off indicates the CPU time consumed during SQL statement execution is not captured.

Default value: on

enable_stmt_track

Parameter description: Specifies whether to enable the full/slow SQL statement feature.

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

Value range: Boolean

• on: Full/Slow SQL capture is enabled.
• off: Full /Slow SQL capture is disabled.

Default value: on

track_stmt_session_slot

Parameter description: Specifies the maximum number of full/slow SQL statements that can be cached in a session. If the number of full/slow SQL statements exceeds this value, new statements will not be traced until the flush thread flushes the cached statements to the disk to reserve idle space.

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

Value range: an integer ranging from 0 to 2147483647

Default value: 1000

track_stmt_details_size

Parameter description: Specifies the maximum size (in bytes) of execution events that can be collected by a single statement.

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

Value range: an integer ranging from 0 to 100000000

Default value: 4096

track_stmt_retention_time

Parameter description: Specifies the retention period of full/slow SQL statement records. This parameter is a combination of parameters. This parameter is read every 60 seconds and records exceeding the retention period are deleted. 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

This parameter consists of two parts in the format of 'full sql retention time, slow sql retention time'.

full sql retention time indicates the retention time of full SQL statements. The value ranges from 0 to 86400.

slow sql retention time indicates the retention time of slow SQL statements. The value ranges from 0 to 604800.

Default value: 3600,604800

track_stmt_stat_level

Parameter description: Determines the level of statement execution tracing.

This parameter is a USERSET parameter. Set it based on instructions provided in Table 1 GUC parameters. The value is case-insensitive.

Value range: a string

This parameter consists of two parts in the format of 'full sql stat level, slow sql stat level'.

The first part indicates the tracing level of full SQL statements. The value can be OFF, L0, L1, or L2.

The second part indicates the tracing level of slow SQL statements. The value can be OFF, L0, L1, or L2.

NOTE: If the full SQL tracing level is not OFF, the current SQL tracing level is the higher level (L2 > L1 > L0) of the full SQL and slow SQL statements. For details about the levels, see Table 1 GUC parameters.

Default value: OFF,L0

unique_sql_clean_ratio

Parameter description: Specifies the ratio of the number of unique SQL entries that are automatically eliminated each time to the preset upper limit (instr_unique_sql_count) when the number of unique SQL entries generated in the system is greater than or equal to instr_unique_sql_count.

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

Value range: Double type ranging from 0 to 0.2.

Default value: 0.1

CAUTION:

• If this parameter is set to a small value, only a few entries are cleared each time, which may cause frequent clearance. If this parameter is set to a large value, a large number of entries are cleared each time, which may cause frequent insertion. The recommended value is 0.1.
• If unique_sql_clean_ratio is set to 0, automatic elimination is not disabled. Use enable_auto_clean_unique_sql to determine whether to enable automatic elimination. When automatic elimination is enabled and unique_sql_clean_ratio is set to 0, unique_sql_clean_ratio is automatically reset to the default value 0.1.

enable_auto_clean_unique_sql

Parameter description: Specifies whether to enable the automatic elimination function of unique SQL statements when the number of unique SQL statements generated in the system is greater than or equal to the value of instr_unique_sql_count.

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

Value range: Boolean

Default value: off

CAUTION: Some snapshot information comes from unique SQL statements. Therefore, when automatic elimination is enabled, if the selected start snapshot and end snapshot exceed the elimination time, the WDR report cannot be generated.