----- Original Message ----- From: "Nathan Barnett" <[EMAIL PROTECTED]> To: "'Mitch Vincent'" <[EMAIL PROTECTED]> Sent: Friday, July 21, 2000 3:03 PM Subject: RE: [GENERAL] Sort > Here is the query: > > SELECT Impression.AdNumber_AdNum, > Impression.Webmaster_WebmasterNum, > Impression.Banner_BannerNum, COUNT(Click.ClickNum) > AS ClickCount > FROM Impression INNER JOIN > Click ON > Impression.ImpressionNum = Click.Impression_ImpressionNum > GROUP BY Impression.AdNumber_AdNum, > Impression.Webmaster_WebmasterNum, > Impression.Banner_BannerNum > > ----------------- > Nathan Barnett > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On > Behalf Of Mitch Vincent > Sent: Friday, July 21, 2000 2:48 PM > To: Nathan Barnett; [EMAIL PROTECTED] > Subject: Re: [GENERAL] Sort > > > Show the query and maybe someone could help :-) > > ----- Original Message ----- > From: "Nathan Barnett" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Friday, July 21, 2000 2:33 PM > Subject: [GENERAL] Sort > > > > I'm currently using v7.0.2 of PostgreSQL. > > > > I have a query that performs a group by on three columns. The EXPLAIN of > > the query is as follows: > > > > Aggregate (cost=4116.05..4125.47 rows=94 width=24) > > -> Group (cost=4116.05..4123.12 rows=942 width=24) > > -> Sort (cost=4116.05..4116.05 rows=942 width=24) > > -> Nested Loop (cost=0.00..4069.52 rows=942 width=24) > > -> Seq Scan on click (cost=0.00..15.42 rows=942 > > width=8) > > -> Index Scan using impression_pkey on impression > > (cost=0.00..4.29 rows=1 width=16) > > > > I need to speed up this query. I have already created an index on the > three > > columns query_idx(columna, columnb,columnc). Is there some other index > that > > I could add which would speed up the query. There is a high frequency in > > the table of each group. Each group probably makes up 10% of the table. > > Does this force a sequence scan when sorting and grouping? Basically just > > looking for suggestions. > > > > > > ---------------- > > Nathan Barnett > > > > > > >
