Re: [GENERAL] 50 MB Table
От | JB |
---|---|
Тема | Re: [GENERAL] 50 MB Table |
Дата | |
Msg-id | 38C67C6B.44FC32A2@kw.igs.net обсуждение исходный текст |
Ответ на | Re: [GENERAL] 50 MB Table (m.malicky@landesmuseum-linz.ac.at) |
Список | pgsql-general |
After much futzing and fiddling I've determined, umm, well very little regarding my problem but a little more about PG. The LIKE query does use the index if and only if, the '%' is at the tail of the string and there is only one '%' in the string. So LIKE 'MAIN%' does use the index but LIKE '%MAIN%' won't. This was verified on the HACKERS list. This means that the 'substring' query that I used should be a heck of a lot slower. EXPLAIN bears this out where the 'substring' query looked at 15,000 rows +- and the LIKE 'MAIN%' used 30 rows. In practise tho, I still wait for the LIKE query for a lot longer than the 'substring' one. The problem, I think I can safely say, is not here. Which leaves me with the setup, implementation, memory usage, OS, permissions, etc. Sorry for all the traffic and confusion. I'll report back when I figure this out. cheers jb -- This is the first age that's paid much attention to the future, which is a little ironic since we may not have one. -- Arthur Clarke
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