Re: Does PostgreSQL check database integrity at startup?

Edson Carlos Ericksson Richter <richter@xxxxxxxxxxxxxx> · Tue, 26 Dec 2017 13:37:36 -0200



    Em 26/12/2017 12:25, Pavel Stehule escreveu:

    
          2017-12-26 14:44 GMT+01:00 Martin
            Marques <martin.marques@xxxxxxxxxxxxxxx>:

            El
              26/12/17 a las 09:52, Edson Carlos Ericksson Richter
              escribió:

              > Recently I had a problem with a base file with size 0
              in a standby server.

              >

              > This raised one question: does PostgreSQL (9.6.6)
              check base integrity

              > at startup?

              >

              > At least if there are 0 byte size files in base dir?
              Or CRC? Something?

              
              Yes it has CRC check, but only if you initialize the
              cluster with

              --data-checksums, and there's a price to pay in
              performance.

              
            It has CRC check, but it is used in runtime - when data
              are necessary 

            
            So Postgres usually check nothing on start - few system
              tables and indexes
            

            Regards
            

            Pavel

            
                  --

                  Martín Marqués                http://www.2ndQuadrant.com/

                  PostgreSQL Development, 24x7 Support, Training &
                  Services

                  
    Any tips to make database server don't start if corrupt?

    If I can change the startup script to make some checks before
    effectively starting the database, what would be the
    recommendations?

    
    One that seems obvious to me are empty data files (something like
    "find -size 0 $PG_DATA/base")...

    But I'm sure that more experienced PostgreSQL DBA would have more
    tests to check before startup.

    
    Thanks,

    
    Edson