vacuum and table locking
От | John Scalia |
---|---|
Тема | vacuum and table locking |
Дата | |
Msg-id | 551EB8D4.7050406@gmail.com обсуждение исходный текст |
Ответы |
Re: vacuum and table locking
Re: vacuum and table locking Re: vacuum and table locking Re: vacuum and table locking |
Список | pgsql-admin |
Hi all, I have a question regarding vacuum and locking, but since I currently don't have access to my servers (maintenance activities),I can't verify on my own. I know that VACUUM has at least four variants. OK, actually two with ability to add ANALYZE after the operation. Here we go: VACUUM (VACUUM ANALYZE) - shouldn't need to lock the table(?). I'm looking at the Douglas' book "PostgreSQL" on page 804where it claims the operation does not require exclusive access. VACUUM FULL (VACUUM FULL ANALYZE) - will need to lock the table, but I'm thinking this may only take a couple of millisecondsas I think this builds a temporary table from the one being vacuumed and then when complete, drops the old table and renames the temporary. So the lock should only be during thismove, or does it lock the table for the entirety? Is this correct? And how does it then resolve say another deletion in the table that occurs while the VACUUM is in operation?I hope that is clearly expressed. -- Jay
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