Re: SELECT * FROM <table> LIMIT 1; is really slow
От
Tom Lane
Тема
Re: SELECT * FROM <table> LIMIT 1; is really slow
Дата
Msg-id
5660.1085624479@sss.pgh.pa.us
Ответ на
Re: SELECT * FROM <table> LIMIT 1; is really slow (David Blasby)
Список
Дерево обсуждения
SELECT * FROM <table> LIMIT 1; is really slow David Blasby <dblasby@refractions.net>
Re: SELECT * FROM <table> LIMIT 1; is really slow Tom Lane <tgl@sss.pgh.pa.us>
Re: SELECT * FROM <table> LIMIT 1; is really slow Christopher Kings-Lynne <chriskl@familyhealth.com.au>
Re: SELECT * FROM <table> LIMIT 1; is really slow Tom Lane <tgl@sss.pgh.pa.us>
Re: SELECT * FROM <table> LIMIT 1; is really slow Dennis Bjorklund <db@zigo.dhs.org>
Re: SELECT * FROM <table> LIMIT 1; is really slow Tom Lane <tgl@sss.pgh.pa.us>
Re: SELECT * FROM <table> LIMIT 1; is really slow Manfred Koizar <mkoi-pg@aon.at>
Re: SELECT * FROM <table> LIMIT 1; is really slow Tom Lane <tgl@sss.pgh.pa.us>
Re: SELECT * FROM <table> LIMIT 1; is really slow Manfred Koizar <mkoi-pg@aon.at>
Re: SELECT * FROM <table> LIMIT 1; is really slow Alvaro Herrera <alvherre@dcc.uchile.cl>
Re: SELECT * FROM <table> LIMIT 1; is really slow Manfred Koizar <mkoi-pg@aon.at>
Re: SELECT * FROM <table> LIMIT 1; is really slow Tom Lane <tgl@sss.pgh.pa.us>
Re: SELECT * FROM <table> LIMIT 1; is really slow Alvaro Herrera <alvherre@dcc.uchile.cl>
Re: SELECT * FROM <table> LIMIT 1; is really slow Tom Lane <tgl@sss.pgh.pa.us>
Re: SELECT * FROM <table> LIMIT 1; is really slow Alvaro Herrera <alvherre@dcc.uchile.cl>
Re: SELECT * FROM <table> LIMIT 1; is really slow Tom Lane <tgl@sss.pgh.pa.us>
Re: SELECT * FROM <table> LIMIT 1; is really slow Alvaro Herrera <alvherre@dcc.uchile.cl>
Re: SELECT * FROM <table> LIMIT 1; is really slow Tom Lane <tgl@sss.pgh.pa.us>
Re: SELECT * FROM <table> LIMIT 1; is really slow Alvaro Herrera <alvherre@dcc.uchile.cl>
Re: SELECT * FROM <table> LIMIT 1; is really slow Alvaro Herrera <alvherre@dcc.uchile.cl>
Re: SELECT * FROM <table> LIMIT 1; is really slow Manfred Koizar <mkoi-pg@aon.at>
Re: SELECT * FROM <table> LIMIT 1; is really slow Alvaro Herrera <alvherre@dcc.uchile.cl>
Nested transactions and tuple header info Bruce Momjian <pgman@candle.pha.pa.us>
Re: Nested transactions and tuple header info Tom Lane <tgl@sss.pgh.pa.us>
Re: Nested transactions and tuple header info Bruce Momjian <pgman@candle.pha.pa.us>
Re: Nested transactions and tuple header info Tom Lane <tgl@sss.pgh.pa.us>
Re: Nested transactions and tuple header info Bruce Momjian <pgman@candle.pha.pa.us>
Re: Nested transactions and tuple header info Alvaro Herrera <alvherre@dcc.uchile.cl>
Re: Nested transactions and tuple header info Bruce Momjian <pgman@candle.pha.pa.us>
Re: Nested transactions and tuple header info Tom Lane <tgl@sss.pgh.pa.us>
Re: Nested transactions and tuple header info Alvaro Herrera <alvherre@dcc.uchile.cl>
Re: Nested transactions and tuple header info Tom Lane <tgl@sss.pgh.pa.us>
Re: Nested transactions and tuple header info Bruce Momjian <pgman@candle.pha.pa.us>
Re: Nested transactions and tuple header info Bruce Momjian <pgman@candle.pha.pa.us>
Re: Nested transactions and tuple header info Alvaro Herrera <alvherre@dcc.uchile.cl>
Re: Nested transactions and tuple header info Alvaro Herrera <alvherre@dcc.uchile.cl>
Re: Nested transactions and tuple header info Alvaro Herrera <alvherre@dcc.uchile.cl>
Re: Nested transactions and tuple header info Tom Lane <tgl@sss.pgh.pa.us>
Re: Nested transactions and tuple header info Alvaro Herrera <alvherre@dcc.uchile.cl>
Re: Nested transactions and tuple header info Bruce Momjian <pgman@candle.pha.pa.us>
Re: SELECT * FROM <table> LIMIT 1; is really slow Manfred Koizar <mkoi-pg@aon.at>
Re: SELECT * FROM <table> LIMIT 1; is really slow Gaetano Mendola <mendola@bigfoot.com>
Re: SELECT * FROM <table> LIMIT 1; is really slow David Blasby <dblasby@refractions.net>
Re: SELECT * FROM <table> LIMIT 1; is really slow Tom Lane <tgl@sss.pgh.pa.us>
Re: SELECT * FROM <table> LIMIT 1; is really slow pgsql@mohawksoft.com
Re: SELECT * FROM <table> LIMIT 1; is really slow David Blasby <dblasby@refractions.net>
Re: SELECT * FROM <table> LIMIT 1; is really slow David Blasby <dblasby@refractions.net>
Re: SELECT * FROM <table> LIMIT 1; is really slow Tom Lane <tgl@sss.pgh.pa.us>
Re: SELECT * FROM <table> LIMIT 1; is really slow Paul Ramsey <pramsey@refractions.net>
David Blasby writes: > I have another copy of this table in another database - vacuum analyse > verbose says its "only" 1,500,000 pages (vs 2,800,000). Hmm ... this is consistent with the idea that you did an UPDATE affecting every row of the table. That would generate N new rows which would all get added to the end of the table, if there were no dead space available within the table. After commit you have a lot of pages worth of dead tuples followed by a lot of pages worth of live tuples. Plain VACUUM cannot do much to fix this since it doesn't move rows around. VACUUM FULL will fix it, but its index-update overhead is high enough that CLUSTER is a better deal. See followup message discussing ALTER TABLE as another alternative. regards, tom lane
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