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    Knowledge articles -Performance/Tuning

    How do I monitor and collect VACUUM processing statistics?KB5001

    You can refer to the pg_stat_all_tables view to check when the latest VACUUM ran for a database object. Monitoring should be enabled to capture the details and check for how long the VACUUM process ran.

    You can capture the details using any of the following methods:

    You can also run VACUUM manually to see how much time the VACUUM process takes.

    Applicable to

    Product: FUJITSU Enterprise Postgres SE, FUJITSU Enterprise Postgres AE, FUJITSU Enterprise Postgres for Kubernetes, PostgreSQL

    Architecture: X86, S390x

    Operating System: Windows, Linux

    Versions: from 9.5

    Long-term operations cause fragmentation of tables and indexes, which result in performance degradation. Are there cases when I should run something other than AUTOVACUUM (e.g., VACUUM FULL)? What indicators should I use to judge? Are there any other factors causing performance degradation in long-term operations?KB5002

    In most installations, it is sufficient to run AUTOVACCUM. If you are experiencing fragmentation, you might have to adjust the autovacuuming parameters to obtain the best results.

    For more information, refer to PostgreSQL 13.1 documentation > Chapter 24 - Routine Database Maintenance Tasks > 24.1 - Routine Vacuuming.

    Because long-term operations can degrade database access performance, consider periodically running the REINDEX command to reorganize indexes. There is no formula available to estimate the execution time for REINDEX, so please refer to the actual measurement in your environment.

    For more information, refer to FUJITSU Enterprise Postgres 13 Operation Guide > Chapter 7 - Periodic Operations > 7.5 - Reorganizing Indexes.

    Applicable to

    Product: FUJITSU Enterprise Postgres SE, FUJITSU Enterprise Postgres AE, FUJITSU Enterprise Postgres for Kubernetes, PostgreSQL

    Architecture: X86, S390x

    Operating System: Windows, Linux

    Versions: from 9.5

    How do I change the WAL segment size?KB5003

    The WAL segment size can be changed when creating the instance using initdb. The default size of each WAL segment size is 16MB.

    initdb provides the option --wal-segsize to specify the size of WAL segment files when creating the instance.

    You cannot change the WAL segment size after initializing the database cluster.

    Applicable to

    Product: FUJITSU Enterprise Postgres SE, FUJITSU Enterprise Postgres AE, FUJITSU Enterprise Postgres for Kubernetes, PostgreSQL

    Architecture: X86, S390x

    Operating System: Windows, Linux

    Versions: from 9.5

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