Re: how postgresql request the computer resources
От | Michael Best |
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Тема | Re: how postgresql request the computer resources |
Дата | |
Msg-id | 43614D9F.9010600@pendragon.org обсуждение исходный текст |
Ответ на | Re: how postgresql request the computer resources (Richard Huxton <dev@archonet.com>) |
Ответы |
Re: how postgresql request the computer resources
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Список | pgsql-performance |
Richard Huxton wrote: >> WITH ANY OF THIS QUERIES MSSQL TAKES NOT MUCH OF 7 SECONDS.... > > > In which case they make a bad choice for showing PostgreSQL is faster > than MSSQL. Is this the only query you have, or are others giving you > problems too? > > I think count(*) is about the weakest point in PG, but I don't think > there'll be a general solution available soon. As I'm sure someone has > mentioned, whatever else, PG needs to check the row for its visibility > information. > > From the start of your email, you seem to suspect your configuration > needs some work. Once you are happy that your settings in general are > good, you can override some by issuing set statements before your query. > For example: > SET work_mem = 10000; > might well improve example #2 where you had a hash. > > -- > Richard Huxton > Archonet Ltd Someone had suggested keeping a vector table with +1 and -1 for row insertion and deletion and then running a cron to sum the vectors and update a table so that you could select from that table to get the row count. Perhaps some sort of SUM() on a column function. Since this seems like a reasonable approach (or perhaps there may be yet another better mechanism), cannot someone add this sort of functionality to Postgresql to do behind the scenes? -Mike
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