Re: Tablespace symlinks

Achilleas Mantzios <achill@xxxxxxxxxxxxxxxxxxxxx> · Tue, 31 Jan 2017 15:09:20 +0200



    Hello,

      
      the docs say very clearly that is your responsibility to unpack
      the tar files. You might change your script to smth like :

      
      for f in `ls *.tar | grep -v base.tar`; do targ=`basename -s .tar
      $f`; echo 'tblspc='$targ; targdir=`grep $targ
      data/tablespace_map|awk '{print $2}' `; echo 'tblspcloc='$targdir
      ; echo tar xvf $f -C $tblspcloc ; done

      
      experiment a little with the above, change .tar to .tar.gz , I
      added echo before tar xvf for testing purposes.

      
      On 31/01/2017 10:54, Slavcho Trnkovski wrote:

    
        Hi,
         
        File content:
        -bash-4.2$ more
            tablespace_map
        16408 /pgdata/tablespaces/db1_lob
        16409
            /pgdata/tablespaces/db1_data
        16410 /pgdata/tablespaces/db1_index
         
        The problem is that I get errors in step 2:
            “tar Cannot open: No such file or directory…”
         
        So, at which step symbolic links should be
            created by the server?
         
        Regards,
        Slavcho
        --
            

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            From: pgsql-admin-owner@xxxxxxxxxxxxxx
                [mailto:pgsql-admin-owner@xxxxxxxxxxxxxx] On Behalf
                  Of Achilleas Mantzios

                Sent: Monday, January 30, 2017 3:58 PM

                To: pgsql-admin@xxxxxxxxxxxxxx

                Subject: Re:  Tablespace symlinks
          
        
          tar != "the server" . The doc tells you
            the server will consult
            tablespace_map. What does this file look like
                in your base.tar.gz ?

            
            On 30/01/2017 16:24, Slavcho Trnkovski wrote:
        
        
              Hi,
            
            
              I'm
                  using PostgreSQL 9.5.
            
            
              As
                  backup I use pg_basebackup with options
                  --format=t -v -z -P .
            
            
              These
                  are the steps I do for restore:

                  1. 
            
            
              tar
                  -xzf base.tar.gz -C $PGDATA
            
            
              2. 
            
            
              for
                  f in `ls | grep -v base.tar.gz `; do
            
            echo
                "tar  -xf $f -C $PGDATA/pg_tblspc/`echo $f|cut -d'.' -f
                1`" 

                tar -xf $f -C $PGDATA/pg_tblspc/`echo $f|cut -d'.' -f 1`

                done 
            
               
              I ha
                  
              
                 v
              
              e
                  
              
                    problem because
                  symlinks
                    for my tablespaces are not being created in step 1.
              
            
                    According to https://www.postgresql.org/docs/9.5/static/app-pgbasebackup.html
                    :
              
              
                "When
                      tar format mode is used, it is the user's
                      responsibility to unpack each tar file before
                      starting the PostgreSQL server. If there are
                      additional tablespaces, the tar files for them
                      need to be unpacked in the correct locations. In
                      this case the symbolic links for those tablespaces
                      will be created by the server according to the
                      contents of the tablespace_map file
                      that is included in the base.tar file."
              
              
                my
                    understanding is that these symbolic links should be
                    created with the first step.
              
              
                I
                    was using same approach with PostgreSQL 9.4, and it
                    was OK.
              
              
                So,
                    is this new behavior in 9.5 (so I shall handle it
                    manually), or I am missing something?
              
              
                Regards,
              
              
                Slavcho
              
              
        -- 
        Achilleas Mantzios
        IT DEV Lead
        IT DEPT
        Dynacom Tankers Mgmt
      
    
    -- 
Achilleas Mantzios
IT DEV Lead
IT DEPT
Dynacom Tankers Mgmt