Re: Not Picking Index

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От George Pavlov
Тема Re: Not Picking Index
Дата
Msg-id 8C5B026B51B6854CBE88121DBF097A8684DA43@ehost010-33.exch010.intermedia.net
обсуждение исходный текст
Ответ на Re: Not Picking Index  (Tom Lane <tgl@sss.pgh.pa.us>)
Ответы Re: Not Picking Index  (Tom Lane <tgl@sss.pgh.pa.us>)
Список pgsql-performance
> Note the DROP INDEX will acquire exclusive lock on the table, so this
> might not be the greatest thing to do in a production environment.
> In PG 8.2 and up there is a sneakier way to do it that won't acquire
> any more lock than the statement-under-test does:
>
>     begin;
>     update pg_index set indisvalid = false
>       where indexrelid = 'soandso'::regclass;
>     explain analyze ...;
>     rollback;

this really smacks of that four-letter word that starts with h... -- i
am glad we have finally come around on the subject :-)

seriously, this is a great technique and an enormous time saver during
query optimization. thanks for sharing!

george

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