Re: insert vs select into performance
От | Michael Glaesemann |
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Тема | Re: insert vs select into performance |
Дата | |
Msg-id | 3FCCED29-F5D9-4AEE-878E-A8F407B1FFEE@seespotcode.net обсуждение исходный текст |
Ответ на | Re: insert vs select into performance (Thomas Finneid <tfinneid@student.matnat.uio.no>) |
Ответы |
Re: insert vs select into performance
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Список | pgsql-performance |
On Jul 17, 2007, at 15:50 , Thomas Finneid wrote: > Michael Glaesemann wrote: >> 2a) Are you using INSERT INTO foo (foo1, foo2, foo2) SELECT foo1, >> foo2, foo3 FROM pre_foo or individual inserts for each row? The >> former would be faster than the latter. > performed with JDBC > > insert into ciu_data_type (id, loc_id, value3, value5, value8, > value9, value10, value11 ) values (?,?,?,?,?,?,?,?) As they're individual inserts, I think what you're seeing is overhead from calling this statement 100,000 times, not just on the server but also the overhead through JDBC. For comparison, try CREATE TABLE ciu_data_type_copy LIKE ciu_data_type; INSERT INTO ciu_data_type_copy (id, loc_id, value3, value5, value8, value9, value10, value11) SELECT id, loc_id, value3, value5, value8, value9, value10, value11 FROM ciu_data_type; I think this would be more comparable to what you're seeing. > I havent done this test in a stored function yet, nor have I tried > it with a C client so far, so there is the chance that it is java/ > jdbc that makes the insert so slow. I'll get to that test soon if > there is any chance my theory makes sence. Just testing in psql with \timing should be fairly easy. Michael Glaesemann grzm seespotcode net
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