Alvaro, Thank you for the explanation. It's really helpfull.
>> Second question is when the wrong summary data is gone? It seems >> vacuum does not help. Do I have to recreate the index (or reindex)? > > Yeah, that's a bit of an open problem: we don't have any mechanism to > mark a block range as needing resummarization, yet. I don't have any > great ideas there, TBH. Some options that were discussed but never led > anywhere: > > 1. whenever a heap tuple is deleted that's minimum or maximum for a > column, mark the index tuple as needing resummarization. One a future > vacuuming pass the index would be updated. (I think this works for > minmax, but I don't see how to apply it to inclusion). > > 2. have block ranges be resummarized randomly during vacuum. > > 3. Have index tuples last for only X number of transactions, marking the > as needing summarization when that expires. > > 4. Have a user-invoked function that re-runs summarization. That way > the user can implement any of the above policies, or others. What about doing resummarization while rechecking the heap data? Best regards, -- Tatsuo Ishii SRA OSS, Inc. Japan English: http://www.sraoss.co.jp/index_en.php Japanese:http://www.sraoss.co.jp -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers