Re: join over 12 tables takes 3 secs to plan
От | Joe Conway |
---|---|
Тема | Re: join over 12 tables takes 3 secs to plan |
Дата | |
Msg-id | 3E14B1C7.9040007@joeconway.com обсуждение исходный текст |
Ответ на | Re: join over 12 tables takes 3 secs to plan (Hilmar Lapp <hlapp@gmx.net>) |
Ответы |
Re: join over 12 tables takes 3 secs to plan
Re: join over 12 tables takes 3 secs to plan |
Список | pgsql-performance |
Hilmar Lapp wrote: > As an added note, appreciating that query optimization is a difficult > problem, and I do think PostgreSQL is a great product. Having said > that, I've written 16-table joins for Oracle and always found them to > plan within a second or two, so that's why I thought there's nothing > special about the query I posted ... I'm not saying this to be bashful > about PostgreSQL, but rather to suggest that apparently there are ways > to do it pretty fast. I could be wrong, but I believe Oracle uses its rule based optimizer by default, not its cost based optimizer. A rule based optimizer will be very quick all the time, but might not pick the best plan all the time, because it doesn't consider the statistics of the data. Any idea which one you were using in your Oracle experience? Joe
В списке pgsql-performance по дате отправления: