PostgreSQL collects various statistics about its internal operations and the usage of database objects, which can be useful for performance tuning and troubleshooting purposes. By default, PostgreSQL enables statistics collection, but you may need to adjust some settings to ensure that the collection is effective.
To configure PostgreSQL for statistics collection, you can follow these steps:
1. Modify the postgresql.conf file to enable the collection of statistics by setting track_activities to on. This setting enables the collection of statistics about the current database activity, such as active connections, queries, and transaction status.
2. Modify the postgresql.conf file to enable the collection of statement-level statistics by setting track_counts to on. This setting enables the collection of statistics about the number of rows processed by each query, as well as the number of disk and memory I/O operations performed by each query.
3. Modify the postgresql.conf file to adjust the level of detail collected by setting track_io_timing to on. This setting enables the collection of detailed statistics about the timing of disk and memory I/O operations, which can be useful for identifying bottlenecks in I/O performance.
4. Use the pg_stat_* views to retrieve statistics about database objects and operations. For example, to view the number of rows processed by each query, you can execute the following query:
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SELECT query, rows FROM pg_stat_statements; |
This query uses the pg_stat_statements view to retrieve statistics about the execution of SQL statements.
5. Use the pg_settings view to view and modify the configuration settings related to statistics collection. For example, to view the current value of the track_activities setting, you can execute the following query:
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SELECT name, setting FROM pg_settings WHERE name = 'track_activities'; |
This query uses the pg_settings view to retrieve the current value of the track_activities setting.
It is recommended to regularly review and analyze the collected statistics to identify performance bottlenecks and opportunities for optimization. Additionally, be aware that collecting detailed statistics can have a performance impact, so adjust the settings as needed based on your system’s resources and requirements.