Re: Recommendation to run vacuum FULL in parallel

Ron <ronljohnsonjr@xxxxxxxxx> · Wed, 3 Apr 2019 01:22:02 -0500



    On 4/3/19 12:50 AM, Perumal Raj wrote:

    
            Hi ALL
            

            We are  planning to reclaim unused space from 9.2
              Version postgres Cluster,
            

            Method : VACUUM FULL
          
        
    Does every table have so much free space that it's
    impractical to just let the files just get refilled by normal usage?

    
            DB Size : 500 GB
            Expected space to reclaim 150 GB
            work_mem : 250 MB

            
              maintenance_work_mem : 20 GB
            
            
            Question :
            

            1. vacuumdb --j option (Parallel) not available for
              version 9.2.
              How to run vacuum full in parallel ? At present its
              taking 8Hrs if i run sequential ( vacuum full verbose;)
            

            2. If we run vacuum full, Do we need to run
              REINDEX/ANALYZE exclusively ?
            

            3. What is the best way to run VACUUM FULL with less
              window.
          
        
    A good way to run any task like this in parallel is to
    generate X lists of objects, and then process each list in parallel.

    
    -- 

      Angular momentum makes the world go 'round.