Re: Database size different on Primary and Standby?

Ron <ronljohnsonjr@xxxxxxxxx> · Wed, 18 Jan 2023 20:13:00 -0600



    On 1/18/23 17:09, Hilbert, Karin wrote:

    
      I manage some
          PostgreSQL clusters on Linux.  We have a Primary & two
          Standby servers & for Production, there is also a DR
          server.  We use repmgr for our HA solution & the Standbys
          are cloned from the Primary using the
          repmgr standby clone command.
      

      My manager asked
          for a report of all the user databases & their sizes for
          each server in the cluster.
      I used the psql
          "\l+" command & then extracted the database name
          & the size from the output.
      I expected the
          databases to be the same size on the Standbys as on the
          Primary, but I found that some of the databases were smaller
          on the Standby servers than on the Primary.
      

      For example, the
          output on the Primary for one of the user databases showed
          as:  8997 kB, but on the Standbys, it
            was 8849 kB.
      
        
          I even dropped the database on the Primary & then restored
          it from a backup.  Then checked the sizes again & they
          still showed the difference.
        
          
          I also found that the template1 database on the Primary was 7821 kB,
          but on the Standbys, it was 7673 kB.
        
          Is this normal?  Why would the sizes be different?
      
    
    Maybe it is.  8997 - 8849 = 7821 - 7673 = 148.  That's right: both
    primaries are exatly 148KB larger.

    
    This will tell you where the differences are: $ du -kc $PGDATA

    
    -- 

      Born in Arizona, moved to Babylonia.