From: pgsql-performance-owner@xxxxxxxxxxxxxx [mailto:pgsql-performance-owner@xxxxxxxxxxxxxx] On Behalf Of Tommi K Ok, sorry that I did not add the original message. I thought that it would be automatically added to the message thread. Here is the question again: Is there way to keep query time constant as the database size grows. Should I use partitioning or partial indexes? Thanks, Tommi Kaksonen > Hello, > > I have the following tables and query. I would like to get some help to find out why it is slow and how its performance could be improved. > > Thanks, > Tommi K. > > > --Table definitions--- > CREATE TABLE "Measurement" > ( > id bigserial NOT NULL, > product_id bigserial NOT NULL, > nominal_data_id bigserial NOT NULL, > description text, > serial text, > measurement_time timestamp without time zone, > status smallint, > system_description text, > CONSTRAINT "Measurement_pkey" PRIMARY KEY (id), > CONSTRAINT "Measurement_nominal_data_id_fkey" FOREIGN KEY (nominal_data_id) > REFERENCES "Nominal_data" (id) MATCH SIMPLE > ON UPDATE NO ACTION ON DELETE NO ACTION, > CONSTRAINT "Measurement_product_id_fkey" FOREIGN KEY (product_id) > REFERENCES "Product" (id) MATCH SIMPLE > ON UPDATE NO ACTION ON DELETE NO ACTION > ) > WITH ( > OIDS=FALSE > ); > > CREATE INDEX measurement_time_index > ON "Measurement" > USING btree > (measurement_time); > ALTER TABLE "Measurement" CLUSTER ON measurement_time_index; > > CREATE TABLE "Product" > ( > id bigserial NOT NULL, > name text, > description text, > info text, > system_name text, > CONSTRAINT "Product_pkey" PRIMARY KEY (id) > ) > WITH ( > OIDS=FALSE > ); > > > CREATE TABLE "Extra_info" > ( > id bigserial NOT NULL, > measurement_id bigserial NOT NULL, > name text, > description text, > info text, > type text, > value_string text, > value_double double precision, > value_integer bigint, > value_bool boolean, > CONSTRAINT "Extra_info_pkey" PRIMARY KEY (id), > CONSTRAINT "Extra_info_measurement_id_fkey" FOREIGN KEY (measurement_id) > REFERENCES "Measurement" (id) MATCH SIMPLE > ON UPDATE NO ACTION ON DELETE NO ACTION > ) > WITH ( > OIDS=FALSE > ); > > CREATE INDEX extra_info_measurement_id_index > ON "Extra_info" > USING btree > (measurement_id); > > CREATE TABLE "Feature" > ( > id bigserial NOT NULL, > measurement_id bigserial NOT NULL, > name text, > description text, > info text, > CONSTRAINT "Feature_pkey" PRIMARY KEY (id), > CONSTRAINT "Feature_measurement_id_fkey" FOREIGN KEY (measurement_id) > REFERENCES "Measurement" (id) MATCH SIMPLE > ON UPDATE NO ACTION ON DELETE NO ACTION > ) > WITH ( > OIDS=FALSE > ); > > CREATE INDEX feature_measurement_id_and_name_index > ON "Feature" > USING btree > (measurement_id, name COLLATE pg_catalog."default"); > > CREATE INDEX feature_measurement_id_index > ON "Feature" > USING hash > (measurement_id); > > > CREATE TABLE "Point" > ( > id bigserial NOT NULL, > feature_id bigserial NOT NULL, > x double precision, > y double precision, > z double precision, > status_x smallint, > status_y smallint, > status_z smallint, > difference_x double precision, > difference_y double precision, > difference_z double precision, > CONSTRAINT "Point_pkey" PRIMARY KEY (id), > CONSTRAINT "Point_feature_id_fkey" FOREIGN KEY (feature_id) > REFERENCES "Feature" (id) MATCH SIMPLE > ON UPDATE NO ACTION ON DELETE NO ACTION > ) > WITH ( > OIDS=FALSE > ); > > CREATE INDEX point_feature_id_index > ON "Point" > USING btree > (feature_id); > > CREATE TABLE "Warning" > ( > id bigserial NOT NULL, > feature_id bigserial NOT NULL, > "number" smallint, > info text, > CONSTRAINT "Warning_pkey" PRIMARY KEY (id), > CONSTRAINT "Warning_feature_id_fkey" FOREIGN KEY (feature_id) > REFERENCES "Feature" (id) MATCH SIMPLE > ON UPDATE NO ACTION ON DELETE NO ACTION > ) > WITH ( > OIDS=FALSE > ); > > CREATE INDEX warning_feature_id_index > ON "Warning" > USING btree > (feature_id); > > > ---Query--- > SELECT > f.name, > f.description, > SUM(CASE WHEN p.status_x = 0 AND p.status_y = 0 AND p.status_z = 0 AND warning.id IS NULL THEN 1 ELSE 0 END) AS green_count, > SUM(CASE WHEN p.status_x = 0 AND p.status_y = 0 AND p.status_z = 0 AND warning.id IS NOT NULL THEN 1 ELSE 0 END) AS green_warned_count, > SUM(CASE WHEN NOT (p.status_x = 0 AND p.status_y = 0 AND p.status_z = 0) AND NOT (p.status_x = 2 OR p.status_y = 2 OR p.status_z = 2) AND warning.id IS NULL THEN 1 ELSE 0 END) AS yellow_count, > SUM(CASE WHEN NOT (p.status_x = 0 AND p.status_y = 0 AND p.status_z = 0) AND NOT (p.status_x = 2 OR p.status_y = 2 OR p.status_z = 2) AND warning.id IS NOT NULL THEN 1 ELSE 0 END) AS yellow_warned_count, > SUM(CASE WHEN (p.status_x = 2 OR p.status_y = 2 OR p.status_z = 2) AND warning.id IS NULL THEN 1 ELSE 0 END) AS red_count, > SUM(CASE WHEN (p.status_x = 2 OR p.status_y = 2 OR p.status_z = 2) AND warning.id IS NOT NULL THEN 1 ELSE 0 END) AS red_warned_count, > SUM(CASE WHEN (p.status_x = 1000 OR p.status_y = 1000 OR p.status_z = 1000) AND warning.id IS NOT NULL THEN 1 ELSE 0 END) AS unable_to_measure_count > FROM "Point" p > JOIN "Feature" f ON f.id = p.feature_id > JOIN "Measurement" measurement ON measurement.id = f.measurement_id > JOIN "Product" product ON product.id = measurement.product_id > LEFT JOIN "Warning" warning ON f.id = warning.feature_id > WHERE (product.name ILIKE 'Part 1') AND > measurement.measurement_start_time >= '2015-06-18 17:00:00' AND > measurement.measurement_start_time <= '2015-06-18 18:00:00' AND > measurement.id NOT IN(SELECT measurement_id FROM "Extra_info" e > WHERE e.measurement_id = measurement.id AND e.description = 'Clamp' AND e.value_string ILIKE 'Clamped%') > GROUP BY f.name, f.description; > > > ---Explain Analyze--- > GroupAggregate (cost=1336999.08..1337569.18 rows=5562 width=33) (actual time=6223.622..6272.321 rows=255 loops=1) > Buffers: shared hit=263552 read=996, temp read=119 written=119 > -> Sort (cost=1336999.08..1337012.98 rows=5562 width=33) (actual time=6223.262..6231.106 rows=26265 loops=1) > Sort Key: f.name, f.description > Sort Method: external merge Disk: 936kB > Buffers: shared hit=263552 read=996, temp read=119 written=119 > -> Nested Loop Left Join (cost=0.00..1336653.08 rows=5562 width=33) (actual time=55.792..6128.875 rows=26265 loops=1) > Buffers: shared hit=263552 read=996 > -> Nested Loop (cost=0.00..1220487.17 rows=5562 width=33) (actual time=55.773..5910.852 rows=26265 loops=1) > Buffers: shared hit=182401 read=954 > -> Nested Loop (cost=0.00..22593.53 rows=8272 width=27) (actual time=30.980..3252.869 rows=38831 loops=1) > Buffers: shared hit=972 read=528 > -> Nested Loop (cost=0.00..657.24 rows=22 width=8) (actual time=0.102..109.577 rows=103 loops=1) > Join Filter: (measurement.product_id = product.id) > Rows Removed by Join Filter: 18 > Buffers: shared hit=484 read=9 > -> Seq Scan on "Product" product (cost=0.00..1.04 rows=1 width=8) (actual time=0.010..0.019 rows=1 loops=1) > Filter: (name ~~* 'Part 1'::text) > Rows Removed by Filter: 2 > Buffers: shared hit=1 > -> Index Scan using measurement_start_time_index on "Measurement" measurement (cost=0.00..655.37 rows=67 width=16) (actual time=0.042..109.416 rows=121 loops=1) > Index Cond: ((measurement_start_time >= '2015-06-18 17:00:00'::timestamp without time zone) AND (measurement_start_time <= '2015-06-18 18:00:00'::timestamp without time zone)) > Filter: (NOT (SubPlan 1)) > Buffers: shared hit=483 read=9 > SubPlan 1 > -> Index Scan using extra_info_measurement_id_index on "Extra_info" e (cost=0.00..9.66 rows=1 width=8) (actual time=0.900..0.900 rows=0 loops=121) > Index Cond: (measurement_id = measurement.id) > Filter: ((value_string ~~* 'Clamped%'::text) AND (description = 'Clamp'::text)) > Rows Removed by Filter: 2 > Buffers: shared hit=479 read=7 > -> Index Scan using feature_measurement_id_and_name_index on "Feature" rf (cost=0.00..993.40 rows=370 width=35) (actual time=28.152..30.407 rows=377 loops=103) > Index Cond: (measurement_id = measurement.id) > Buffers: shared hit=488 read=519 > -> Index Scan using point_feature_id_index on "Point" p (cost=0.00..144.80 rows=1 width=14) (actual time=0.067..0.067 rows=1 loops=38831) > Index Cond: (feature_id = f.id) > Buffers: shared hit=181429 read=426 > -> Index Scan using warning_feature_id_index on "Warning" warning (cost=0.00..20.88 rows=1 width=16) (actual time=0.007..0.007 rows=0 loops=26265) > Index Cond: (f.id = feature_id) > Buffers: shared hit=81151 read=42 > Total runtime: 6273.312 ms > > > ---Version--- > PostgreSQL 9.2.1, compiled by Visual C++ build 1600, 64-bit > > > ---Table sizes--- > Extra_info 1223400 rows > Feature 185436000 rows > Measurement 500000 rows > Point 124681000 rows > Warning 11766800 rows > > ---Hardware--- > Intel Core i5-2320 CPU 3.00GHz (4 CPUs) > 6GB Memory > 64-bit Operating System (Windows 7 Professional) > WD Blue 500GB HDD - 7200 RPM SATA 6 Gb/s 16MB Cache > > ---History--- > Query gets slower as more data is added to the database > > ---Maintenance--- > Autovacuum is used with default settings > > Tommi Kaksonen <t2nn2t(at)gmail(dot)com> wrote: I don’t see a reason to partition such small data. What I do see is you attempting to run a big query on what looks like a small desktop pc. 6GB of ram, especially under Windows 7, isn’t enough ram for a database server. Run the query on a normal small server of say 16gb and it should perform fine. IMO. Mike |
