Re: Optimizer not using index on 120M row table
От | Jim C. Nasby |
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Тема | Re: Optimizer not using index on 120M row table |
Дата | |
Msg-id | 20030407232941.P31861@flake.decibel.org обсуждение исходный текст |
Ответ на | Re: Optimizer not using index on 120M row table (Tom Lane <tgl@sss.pgh.pa.us>) |
Ответы |
Re: Optimizer not using index on 120M row table
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Список | pgsql-general |
On Tue, Apr 08, 2003 at 12:02:55AM -0400, Tom Lane wrote: > The authoritative reference is pg_type.typalign ... see > http://www.ca.postgresql.org/users-lounge/docs/7.3/postgres/catalog-pg-type.html > In this example, your next field requires integer alignment, so the > two bytes "saved" by using smallint disappear into the padding. Thanks, makes sense to me now. Next question... will pgsql intelligently order things in an item record so that they're stored most efficiently? ie: group all the byte-align stuff together, all the 2-byte aligned stuff, etc.? Or will it just go off of the order defined in the create table statement? If it's the later, is there any way to re-organize things without rebuilding the table from scratch? What other things should be considered for column ordering? Thanks! -- Jim C. Nasby (aka Decibel!) jim@nasby.net Member: Triangle Fraternity, Sports Car Club of America Give your computer some brain candy! www.distributed.net Team #1828 Windows: "Where do you want to go today?" Linux: "Where do you want to go tomorrow?" FreeBSD: "Are you guys coming, or what?"
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