Re: [HACKERS] DROP TABLE inside a transaction block
От | Bruce Momjian |
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Тема | Re: [HACKERS] DROP TABLE inside a transaction block |
Дата | |
Msg-id | 200003080706.CAA17536@candle.pha.pa.us обсуждение исходный текст |
Ответ на | Re: [HACKERS] DROP TABLE inside a transaction block (Tom Lane <tgl@sss.pgh.pa.us>) |
Ответы |
Re: [HACKERS] DROP TABLE inside a transaction block
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Список | pgsql-hackers |
> If we change the implementation so that the files are named after > the (fixed, never-changed-after-creation) table OID, then RENAME > TABLE is no problem: it affects *nothing* except the relname field > of the table's pg_class row, and either that row update is committed > or it ain't. > > But if the physical file names contain the logical table name, we > have to be prepared to rename those files in sync with the transaction > commit that makes the pg_class update valid. Quite aside from any > implementation effort involved, the critical point is this: it is > *not possible* to ensure that that collection of changes is atomic. > At best, we can make the window for failure small. > > Bruce seems to be willing to accept a window of failure for RENAME > TABLE in order to make database admin easier. That is very possibly > the right tradeoff --- but it is *not* an open-and-shut decision. > We need to talk about it. How about creating a hard link during RENAME, and you can just remove the old link on commit or remove the new link on transaction rollback? We can register this in the at_exit processing too if you think it is necessary to clean it up on a backend crash that never gets to an abort, though I think abort is always called. -- Bruce Momjian | http://www.op.net/~candle 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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