Re: Seq. scan when using comparison operators, why?
От | Bill Gribble |
---|---|
Тема | Re: Seq. scan when using comparison operators, why? |
Дата | |
Msg-id | 1018278214.27438.71.camel@flophouse обсуждение исходный текст |
Ответ на | Re: Seq. scan when using comparison operators, why? [netaktiv.com #150] (Martijn van Oosterhout <kleptog@svana.org>) |
Ответы |
Re: Seq. scan when using comparison operators, why?
|
Список | pgsql-general |
On Mon, 2002-04-08 at 07:45, Martijn van Oosterhout wrote: > "Properly" in your opinion. It's more likely that postgres has a better idea > of which one is faster... This seems to be the standard response to any message questioning the query planner's strategy. In my opinion, such a response is condescending, discourages user feedback about postgres performance in real database applications, and fundamentally misses the point. The point is that postgres performance frequently sucks on queries that should be fast. Any technical explanation about how postgres knows more than a particular user about its own guts doesn't really bear on that issue. People are trying to be helpful by submitting query plans that look suspicious... but they aren't just EXPLAINing in order to poke holes in the query planner as entertainment, they are EXPLAINing to try to figure out why it takes so long to get results from a simple query that another DBMS can do in a fraction of the time. You seem to be trying to put an end to the discussion by saying "postgres knows how to plan queries, so keep your opinions to yourself". Why is this user even concerned about the way Postgres is executing the query? Because he has a reasonable expectation that the query should be faster than sequential scan of all records, and it's not. Unless you can either explain why that expectation is not reasonable, or explain why postgres fails to meet reasonable expectations, you're just sneering at a user reporting a problem. Not good public relations. Thanks, Bill Gribble
В списке pgsql-general по дате отправления: