Re: 8.2rc1: vacuum full fills up disk space
От | Thomas H. |
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Тема | Re: 8.2rc1: vacuum full fills up disk space |
Дата | |
Msg-id | 0faa01c7124e$81d09cb0$0201a8c0@iwing обсуждение исходный текст |
Ответ на | 8.2rc1: vacuum full fills up disk space ("Thomas H." <me@alternize.com>) |
Список | pgsql-bugs |
>> well yes, as the system is "live", users are browsing the website. but >> all queries that try to access the table in question are stalled at the >> moment. when querying server status i'm seeing lots of queries that are >> waiting for access to the table. >> >> would vacuum freeze be faster? > > Vacuum freeze won't move tuples so it won't reclaim any more space than a > normal vacuum. Cluster, however, rewrites the whole table and compacts the > space, and runs faster than vacuum full on a badly bloated table. It will > also recreate all indexes. will give it a try later on, thanks! > > In the future, instead of updating a whole table with UPDATE, you should > consider doing a SELECT INTO to create a new table, dropping the old table > and renaming the new one in place of the old one. the problem is: the table was far from being bloated, IMO. it was 2 days old, every record at most 2-3 times updated. the space needed for the table dropped from 400mb to roughly 200mb after the 1.5hr vacuum full... i've never had such a long vacuuming time before, even on tables that are much larger and contains more dead rows. the table uses tsearch2 and a gin-index, could that be the problem? the gin faq says a drop/create index would be much faster than a reindex. maybe this is also true when vacuuming a table with a gin-index? - thomas
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