Index bloat in Greenplum

Table and Index Bloat view



        schemaname, tablename, reltuples::bigint, relpages::bigint, otta,

        ROUND(CASE WHEN otta=0 THEN 0.0 ELSE sml.relpages/otta::numeric END,1) AS tbloat,

        relpages::bigint - otta AS wastedpages,

        bs*(sml.relpages-otta)::bigint AS wastedbytes,

        pg_size_pretty((bs*(relpages-otta))::bigint) AS wastedsize,

        iname, ituples::bigint, ipages::bigint, iotta,

        ROUND(CASE WHEN iotta=0 OR ipages=0 THEN 0.0 ELSE ipages/iotta::numeric END,1) AS ibloat,

        CASE WHEN ipages < iotta THEN 0 ELSE ipages::bigint - iotta END AS wastedipages,

        CASE WHEN ipages < iotta THEN 0 ELSE bs*(ipages-iotta) END AS wastedibytes,

        CASE WHEN ipages < iotta THEN pg_size_pretty(0) ELSE pg_size_pretty((bs*(ipages-iotta))::bigint) END AS wastedisize

      FROM (


          schemaname, tablename, cc.reltuples, cc.relpages, bs,


            (CASE WHEN datahdr%ma=0 THEN ma ELSE datahdr%ma END))+nullhdr2+4))/(bs-20::float)) AS otta,

          COALESCE(c2.relname,'?') AS iname, COALESCE(c2.reltuples,0) AS ituples, COALESCE(c2.relpages,0) AS ipages,

          COALESCE(CEIL((c2.reltuples*(datahdr-12))/(bs-20::float)),0) AS iotta -- very rough approximation, assumes all cols

        FROM (



            (datawidth+(hdr+ma-(case when hdr%ma=0 THEN ma ELSE hdr%ma END)))::numeric AS datahdr,

            (maxfracsum*(nullhdr+ma-(case when nullhdr%ma=0 THEN ma ELSE nullhdr%ma END))) AS nullhdr2

          FROM (


              schemaname, tablename, hdr, ma, bs,

              SUM((1-null_frac)*avg_width) AS datawidth,

              MAX(null_frac) AS maxfracsum,


                SELECT 1+count(*)/8

                FROM pg_stats s2

                WHERE null_frac<>0 AND s2.schemaname = s.schemaname AND s2.tablename = s.tablename

              ) AS nullhdr

            FROM pg_stats s, (


                (SELECT current_setting('block_size')::numeric) AS bs,

                CASE WHEN substring(v,12,3) IN ('8.0','8.1','8.2') THEN 27 ELSE 23 END AS hdr,

                CASE WHEN v ~ 'mingw32' THEN 8 ELSE 4 END AS ma

              FROM (SELECT version() AS v) AS foo

            ) AS constants

            GROUP BY 1,2,3,4,5

          ) AS foo

        ) AS rs

        JOIN pg_class cc ON cc.relname = rs.tablename

        JOIN pg_namespace nn ON cc.relnamespace = nn.oid AND nn.nspname = rs.schemaname

        LEFT JOIN pg_index i ON indrelid = cc.oid

        LEFT JOIN pg_class c2 ON c2.oid = i.indexrelid

      ) AS sml

      WHERE sml.relpages - otta > 0 OR ipages - iotta > 10

      ORDER BY wastedbytes DESC, wastedibytes DESC;