What's the problem? You are joining two 300 million row tables in 0.15 of a second - seems reasonable. Dmitri > -----Original Message----- > From: pgsql-performance-owner@xxxxxxxxxxxxxx > [mailto:pgsql-performance-owner@xxxxxxxxxxxxxx] On Behalf Of > Amit V Shah > Sent: Thursday, December 08, 2005 11:59 AM > To: 'pgsql-performance@xxxxxxxxxxxxxx' > Subject: [PERFORM] Joining 2 tables with 300 million rows > > > Hi all, > > First of all, please pardon if the question is dumb! Is it > even feasible or normal to do such a thing ! This query is > needed by a webpage so needs to be lightning fast. Anything > beyond 2-3 seconds is unacceptable performance. > > I have two tables > > CREATE TABLE runresult > ( > id_runresult int8 NOT NULL, > rundefinition_id_rundefinition int4 NOT NULL, > measure_id_measure int4 NOT NULL, > value float4 NOT NULL, > "sequence" varchar(20) NOT NULL, > CONSTRAINT pk_runresult_ars PRIMARY KEY (id_runresult), > ) > > > CREATE TABLE runresult_has_catalogtable > ( > runresult_id_runresult int8 NOT NULL, > catalogtable_id_catalogtable int4 NOT NULL, > value int4 NOT NULL, > CONSTRAINT pk_runresult_has_catalogtable PRIMARY KEY > (runresult_id_runresult, catalogtable_id_catalogtable, value) > CONSTRAINT fk_temp FOREIGN KEY (runresult_id_runresult) REFERENCES > runresult(id_runresult) ON UPDATE RESTRICT ON DELETE RESTRICT > ) > > Each table has around 300 million records (will grow to > probably billions). Below is the query and the explain analyze -- > > explain analyze SELECT measure.description, runresult.value > FROM ((((rundefinition INNER JOIN runresult ON > rundefinition.id_rundefinition = > runresult.rundefinition_id_rundefinition) > INNER JOIN runresult_has_catalogtable ON runresult.id_runresult = > runresult_has_catalogtable.runresult_id_runresult) > INNER JOIN runresult_has_catalogtable AS > runresult_has_catalogtable_1 ON runresult.id_runresult = > runresult_has_catalogtable_1.runresult_id_runresult) > INNER JOIN runresult_has_catalogtable AS > runresult_has_catalogtable_2 ON runresult.id_runresult = > runresult_has_catalogtable_2.runresult_id_runresult) > INNER JOIN measure ON runresult.measure_id_measure = > measure.id_measure WHERE > (((runresult_has_catalogtable.catalogtable_id_catalogtable)=52) > AND ((runresult_has_catalogtable_1.catalogtable_id_catalogtable)=54) > AND ((runresult_has_catalogtable_2.catalogtable_id_catalogtable)=55) > AND ((runresult_has_catalogtable.value)=15806) > AND ((runresult_has_catalogtable_1.value)=1) > AND ((runresult_has_catalogtable_2.value) In (21,22,23,24)) > AND ((rundefinition.id_rundefinition)=10106)); > > 'Nested Loop (cost=0.00..622582.70 rows=1 width=28) (actual > time=25.221..150.563 rows=22 loops=1)' ' -> Nested Loop > (cost=0.00..622422.24 rows=2 width=52) (actual > time=25.201..150.177 rows=22 loops=1)' > ' -> Nested Loop (cost=0.00..622415.97 rows=2 > width=32) (actual > time=25.106..149.768 rows=22 loops=1)' > ' -> Nested Loop (cost=0.00..621258.54 rows=15 > width=24) > (actual time=24.582..149.061 rows=30 loops=1)' > ' -> Index Scan using pk_rundefinition on > rundefinition > (cost=0.00..3.86 rows=1 width=4) (actual time=0.125..0.147 > rows=1 loops=1)' > ' Index Cond: (id_rundefinition = 10106)' > ' -> Nested Loop (cost=0.00..621254.54 rows=15 > width=28) (actual time=24.443..148.784 rows=30 loops=1)' > ' -> Index Scan using > runresult_has_catalogtable_value on > runresult_has_catalogtable (cost=0.00..575069.35 rows=14437 > width=8) (actual time=0.791..33.036 rows=10402 loops=1)' > ' Index Cond: (value = 15806)' > ' Filter: > (catalogtable_id_catalogtable = > 52)' > ' -> Index Scan using pk_runresult_ars on > runresult (cost=0.00..3.19 rows=1 width=20) (actual > time=0.007..0.007 rows=0 loops=10402)' > ' Index Cond: (runresult.id_runresult = > "outer".runresult_id_runresult)' > ' Filter: (10106 = > rundefinition_id_rundefinition)' > ' -> Index Scan using > runresult_has_catalogtable_id_runresult > on runresult_has_catalogtable runresult_has_catalogtable_1 > (cost=0.00..76.65 rows=41 width=8) (actual time=0.015..0.017 > rows=1 loops=30)' > ' Index Cond: > (runresult_has_catalogtable_1.runresult_id_runresult = > "outer".runresult_id_runresult)' > ' Filter: ((catalogtable_id_catalogtable = > 54) AND (value > = 1))' > ' -> Index Scan using pk_measure on measure > (cost=0.00..3.12 rows=1 > width=28) (actual time=0.008..0.010 rows=1 loops=22)' > ' Index Cond: ("outer".measure_id_measure = > measure.id_measure)' > ' -> Index Scan using > runresult_has_catalogtable_id_runresult on > runresult_has_catalogtable runresult_has_catalogtable_2 > (cost=0.00..79.42 rows=65 width=8) (actual time=0.007..0.010 > rows=1 loops=22)' > ' Index Cond: > (runresult_has_catalogtable_2.runresult_id_runresult = > "outer".runresult_id_runresult)' > ' Filter: ((catalogtable_id_catalogtable = 55) AND > ((value = 21) OR > (value = 22) OR (value = 23) OR (value = 24)))' > 'Total runtime: 150.863 ms' > > > > ---------------------------(end of > broadcast)--------------------------- > TIP 5: don't forget to increase your free space map settings > The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. 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