hi list, i want to convince people to use postgresql instead of ms-sql server, so i set up a kind of comparission insert data / select data from postgresql / ms-sql server
the table i use was pretty basic, id bigserial dist float8 x float8 y float8 z float8 i filled the table with a function which filled x,y,z with incremental increasing values (1,2,3,4,5,6...) and computing from that the dist value for every tupel (sqrt((x*x)+(y*y)+(z*z))). this works fine for both dbms postgresql needs 13:37 min for 10.000.000 tupel, ms-sql needs 1:01:27 h for 10.000.000 tupel. so far so good. i attached an index on the dist row and started to query the dbs with scripts which select a serial row of 100.000,200.000,500.000 tupels based on the dist row. i randomizly compute the start and the end distance and made a "select avg(dist) from table where dist > startdist and dist < enddist" Did the same with a table with 50.000.000 tupel in ms-sql and postgres. the outcome so far: 100.000 from 50.000.000: postgres: 0.88 sec ms-sql: 0.38 sec 200.000 from 50.000.000: postgres: 1.57 sec ms-sql: 0.54 sec 500.000 from 50.000.000: postgres: 3.66 sec ms-sql: 1.18 sec i try a lot of changes to the postgresql.conf regarding "Tuning PostgreSQL for performance" by Shridhar Daithankar, Josh Berkus which did not make a big diffrence to the answering times from postgresql. i'm pretty fine with the insert time... do you have any hints like compiler-flags and so on to get the answering time from postgresql equal to ms-sql? (btw both dbms were running on exactly the same hardware) i use suse 8.1 postgresql 7.2 compiled from the rpms for using postgis, but that is anothe story... 1.5 gig ram 1.8 mhz intel cpu every help welcome best regards heiko ---------------------------(end of broadcast)--------------------------- TIP 8: explain analyze is your friend