Re: explain analyze cost

Ron <ronljohnsonjr@xxxxxxxxx> · Wed, 12 Dec 2018 16:45:43 -0600



    On 12/12/2018 04:37 PM, Ravi Krishna wrote:

    
      I am
        running explain analyze cost on a SQL which reads from two large
        tables (122mil and 37 mil).  The query is an UPDATE SQL where we
        use derives table in the from clause and then join it back to
        the table being updated.

      
      The
        explain analyze cost itself is taking forever to run. It is
        running for the last 1 hr. Does that actually run the SQL to
        find out the impact of I/O (as indicated in COSTS). 
    
    
    Yes.

    
    https://www.postgresql.org/docs/9.6/sql-explain.html

    
    "The ANALYZE option causes the statement to be actually executed,
    not only planned."

    
      If not,
        what can cause it to run this slow.

      
    -- 

      Angular momentum makes the world go 'round.