Capture From PostgreSQL Using Direct DBMS Log Reading

This section describes the configuration requirements for capturing changes from PostgreSQL using DIRECT capture method. In this capture method (Capture_Method=DIRECT), Data Source Solutions DSS reads transaction log records directly from the DBMS log file using the file I/O.

• The DSS Agent must be installed on the PostgreSQL source database server.

• PostgreSQL configuration file postgresql.conf should have the following settings:

  • wal_level = logical

    SHOW wal_level;
    
    ALTER SYSTEM SET wal_level = logical; -- server restart needed
    

  • archive_mode = on

    SHOW archive_mode;
    
    ALTER SYSTEM SET archive_mode = on; -- server restart needed
    

  • archive_command
    The value of archive_command depends on the location of the archive directory, the operating system and the way archiving is done in a PostgreSQL installation. For example:
    In Unix & Linux,

    SHOW archive_command;
    
    ALTER SYSTEM SET archive_command = 'test ! -f /var/lib/pgsql/9.5/data/archive/%f && cp %p /var/lib/pgsql/9.5/data/archive/%f';   -- server restart needed
    

    In Windows,

    SHOW archive_command;
    
    ALTER SYSTEM SET archive_command = 'copy "%p" "c:\\Program Files\\PostgreSQL\\9.5\\data\\archive\\%f"';   -- server restart needed
    

• The location property XLOG DIRECTORY (PostgreSQL_XLog) must be defined with the directory path to the PostgreSQL transaction log file directory.

The operating system user as which DSS is running when connecting to PostgreSQL should have read permission to the files in this directory either by directly running DSS as the DBMS owner (postgres) or via a trusted executable named dss_postgres.