Re: Looking for tips
От | PFC |
---|---|
Тема | Re: Looking for tips |
Дата | |
Msg-id | op.st6c1qolth1vuj@localhost обсуждение исходный текст |
Ответ на | Re: Looking for tips (Oliver Crosby <ryusei@gmail.com>) |
Список | pgsql-performance |
I can't say wether MySQL is faster for very small queries (like SELECT'ing one row based on an indexed field). That's why I was asking you about the language... I assume you're using a persistent connection. For simple queries like this, PG 8.x seemed to be a lot faster than PG 7.x. Have you tried 8 ? I was asking you which language, because for such really small queries you have to take into account the library overhead. For instance, in PHP a simple query can be 10 times slower in Postgres than in MySQL and I believe it is because php's MySQL driver has seen a lot of optimization whereas the postgres driver has not. Interestingly, the situation is reversed with Python : its best postgres driver (psycopg 2) is a lot faster than the MySQL adapter, and faster than both php adapters (a lot faster). The same query can get (this is from the back of my head): PHP+Postgres 3-5 ms Python+MySQL 1ms PHP+MySQL 0.5 ms Python+Postgres 0.15 ms And yes, I had queries executing in 150 microseconds or so, this includes time to convert the results to native python objects ! This was on a loop of 10000 times the same query. But psycopg2 is fast. The overhead for parsing a simple query and fetching just a row is really small. This is on my Centrino 1.6G laptop.
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