Re: [HACKERS] Re: Top N queries and disbursion
От | Bruce Momjian |
---|---|
Тема | Re: [HACKERS] Re: Top N queries and disbursion |
Дата | |
Msg-id | 199910081633.MAA28027@candle.pha.pa.us обсуждение исходный текст |
Ответ на | Re: [HACKERS] Re: Top N queries and disbursion (Tom Lane <tgl@sss.pgh.pa.us>) |
Список | pgsql-hackers |
> I don't have a better idea right at the moment. I'm open to the idea > that VACUUM should compute more or different statistics, though --- > as long as it doesn't slow things down too much. (How much is too much > would probably depend on how much win the new stats would provide for > normal query-planning. For example, I'd resist making two passes over > the table during VACUUM ANALYZE, but I wouldn't rule it out completely; > you could sell me on it if the advantages were great enough.) > > Hey, you guys are the researchers ... give us a better approach to > keeping table statistics ;-) Yes, I am open to better ideas. The current code does 2-value columns, and unique columns perfectly. The other distributions it gets only approximate answers, but for a one-pass system, that's the best I could do. -- Bruce Momjian | http://www.op.net/~candle maillist@candle.pha.pa.us | (610) 853-3000+ If your life is a hard drive, | 830 Blythe Avenue + Christ can be your backup. | Drexel Hill, Pennsylvania19026
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