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    Knowledge articles - Operation/Maintenance

    If I install FUJITSU Enterprise Postgres on a server that does not join in a domain, and then I join the server to a domain, will FUJITSU Enterprise Postgres functionalities be affected?KB3001

    In principle, this does not affect FUJITSU Enterprise Postgres functionalities as long as you are not changing the server IP or the user who manages FUJITSU Enterprise Postgres.

    However, if your IP changes because of attaching your server to a domain and the old IP was in use (e.g., pg_hba.conf, streaming replication, logical replication etc.), then make sure to update the IP accordingly.

    Also, if you change the user who manages (starts or stops) FUJITSU Enterprise Postgres on the local machine to a domain user, then you must adapt this domain user to be the new owner of the database cluster, and hence you need to update the permissions of domain user so that it can manage the FUJITSU Enterprise Postgres database cluster files and directory.

    Applicable to

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

    Architecture: X86, S390x

    Operating System: Windows, Linux

    Versions: from 9.5

    Can tables and indexes be stored in separate areas?KB3002

    Yes. By leveraging tablespaces, tables and indexes can be placed in separate areas.

    For details, refer to the sections below in PostgreSQL 13.1 Documentation:

    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

    The database server's WAL space disk utilization is 100% and the database process has stopped. How do I solve it?KB3003

    Due to the I/O latency in the WAL archive storage area, the disk containing WAL is full and WAL cannot be written because the copy speed to the archive area is slower than the rate at which WAL data is generated.

    Resolution

    Consider the following:

    • Expand the capacity of the disk that store WAL files
    • Reduce the frequency of database update
    • Use faster disks for WAL archiving

    How to investigate

    • Check the error message in postgresql.log
      The log will contain an error message similar to the one below, stating that the server has stopped because the disk was full and that the system could not write WAL:
      PANIC: could not write to file "pg_wal/waltemp.4920": No space left on device
    • Compare the WAL generation rate and backup rate:
      • Check the WAL generation rate with timestamp intervals of each WAL file under the pg_wal directory.
      • Check the backup rate with timestamp intervals of each file under the archived_wal directory.
      • Confirm that the WAL generation rate is larger than backup rate

    As long as your environment can keep up with the average speed of the WAL generation of the server, the processing speed of the command for archiving is not important. Normal operations continue even if the archive process is slightly delayed, but note that a significantly slower archive process increases the amount of data lost in the event of a disaster. This also means that many segment files waiting to be archived will be stored in $PGDATA/pg_wal, which may cause the disk to be full. It is recommended that you monitor the archive process to ensure that it is working as intended.

    For more details, refer to PostgreSQL 13.1 Documentation > Chapter 25 - Backup and Restore > 25.3.1 - Setting Up WAL Archiving.

    You can also refer to our blog post How to solve the problem if pg_wal is full.

    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 10

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