(Please don't top-post. ) Adrian Demaestri skrev: > */Jeff Davis <pgsql@xxxxxxxxxxx>/* escribió: > > On Mon, 2007-10-22 at 19:24 -0700, Adrian Demaestri wrote: > > Hi, > > I think planner should use other plans than seqscan to solve querys > > like select * from hugetable limit 1, especially when the talbe is > > very large. Is it solved in newer versions or is there some open > > issues about it?. > > thanks > > I'm working with postgres 8.0.1, > > For the query in question, what would be faster than a seqscan? It > doesn't read the whole table, it only reads until it satisfies the limit > clause. > It is not actualy a table, sorry, it is a quite complex view that > involve three large tables. If hugetable isn't a table, you chose a really bad name for it. What you have here is a specific query performing badly, not a generic issue with all queries containing "LIMIT X". You might of course have found a construct which the planner has problems with - but the first step is to let us see the result of EXPLAIN ANALYZE. Anyway, I think you might be hitting this issue: "Fix mis-planning of queries with small LIMIT values due to poorly thought out "fuzzy" cost comparison" (http://www.postgresql.org/docs/8.0/static/release-8-0-4.html) which was fixed in 8.0.4 . You should upgrade. Nis ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
