Re: ALTER TABLE DROP COLUMN
| От | Bruce Momjian |
|---|---|
| Тема | Re: ALTER TABLE DROP COLUMN |
| Дата | |
| Msg-id | 200010091732.NAA11347@candle.pha.pa.us обсуждение |
| Ответ на | Re: ALTER TABLE DROP COLUMN (The Hermit Hacker <scrappy@hub.org>) |
| Ответы |
Re: ALTER TABLE DROP COLUMN
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| Список | pgsql-hackers |
> Basically, move the first 100 rows to the end of the table file, then take > 100 and write it to position 0, 101 to position 1, etc ... that way, at > max, you are using ( tuple * 100 ) bytes of disk space, vs 2x the table > size ... either method is going to lock the file for a period of time, but > one is much more friendly as far as disk space is concerned *plus*, if RAM > is available for this, it might even be something that the backend could > use up to -S blocks of RAM to do it off disk? If I set -S to 64meg, and > the table is 24Meg in size, it could do it all in memory? Yes, I liked that too. -- Bruce Momjian | http://candle.pha.pa.us pgman@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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