Hello, I'm a newbie in postgresql, I've installed it on a Windows XP machine ( I can't use linux, it's a company machine ), I'm courious why this query takes so long
SELECT "Rut Cliente" FROM "Internet_Abril" WHERE "Rut Cliente" NOT IN ((SELECT "Rut Cliente" FROM "Internet_Enero") UNION (SELECT "Rut Cliente" FROM "Internet_Febrero") UNION (SELECT "Rut Cliente" FROM "Internet_Marzo")); it takes about 100 minutes to complete the query. All tables has index created ( Rut Cliente is a VarChar ), and tables has 50.000 records each. The explain for the query tells the following "QUERY PLAN Seq Scan on "Internet_Abril" (cost=19406.67..62126112.70 rows=24731 width=13) Filter: (NOT (subplan)) SubPlan -> Materialize (cost=19406.67..21576.07 rows=136740 width=13) -> Unique (cost=17784.23..18467.93 rows=136740 width=13) -> Sort (cost=17784.23..18126.08 rows=136740 width=13) Sort Key: "Rut Cliente" -> Append (cost=0.00..3741.80 rows=136740 width=13) -> Subquery Scan "*SELECT* 1" (cost=0.00..1233.38 rows=45069 width=13) -> Seq Scan on "Internet_Enero" (cost=0.00..782.69 rows=45069 width=13) -> Subquery Scan "*SELECT* 2" (cost=0.00..1104.06 rows=40353 width=13) -> Seq Scan on "Internet_Febrero" (cost=0.00..700.53 rows=40353 width=13) -> Subquery Scan "*SELECT* 3" (cost=0.00..1404.36 rows=51318 width=13) -> Seq Scan on "Internet_Marzo" (cost=0.00..891.18 rows=51318 width=13) Any help will be apreciated, It's for my thesis saludos Christian ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly