On 17.9.2015 13:32, Eildert Groeneveld wrote: > Dear list > > I am experiencing a rather severe degradation of insert performance > starting from an empty database: > > > 120.000 mio SNPs imported in 28.9 sec - 4.16 mio/sec > 120.000 mio SNPs imported in 40.9 sec - 2.93 mio/sec > 120.000 mio SNPs imported in 49.7 sec - 2.41 mio/sec > 120.000 mio SNPs imported in 58.8 sec - 2.04 mio/sec > 120.000 mio SNPs imported in 68.9 sec - 1.74 mio/sec > 120.000 mio SNPs imported in 77.0 sec - 1.56 mio/sec > 120.000 mio SNPs imported in 85.1 sec - 1.41 mio/sec > 120.000 mio SNPs imported in 94.0 sec - 1.28 mio/sec > 120.000 mio SNPs imported in 103.4 sec - 1.16 mio/sec > 120.000 mio SNPs imported in 108.9 sec - 1.10 mio/sec > 120.000 mio SNPs imported in 117.2 sec - 1.02 mio/sec > 120.000 mio SNPs imported in 122.1 sec - 0.98 mio/sec > 120.000 mio SNPs imported in 132.6 sec - 0.90 mio/sec > 120.000 mio SNPs imported in 142.0 sec - 0.85 mio/sec > 120.000 mio SNPs imported in 147.3 sec - 0.81 mio/sec > 120.000 mio SNPs imported in 154.4 sec - 0.78 mio/sec > 120.000 mio SNPs imported in 163.9 sec - 0.73 mio/sec > 120.000 mio SNPs imported in 170.1 sec - 0.71 mio/sec > 120.000 mio SNPs imported in 179.1 sec - 0.67 mio/sec > 120.000 mio SNPs imported in 186.1 sec - 0.64 mio/sec > > each line represents the insertion of 20000 records in two tables which is > not really a whole lot. Also, these 20000 get inserted in one program run. > The following lines are then again each the execution of that program. > The insert are a text string in one table and a bit varying of length packed > 24000 bits, also no big deal. > > As can be seen the degradation is severe going from 29 sec up to 186 sec > for the same amount of data inserted. > > I have dropped the indices and primary keys, but that did not change the > picture. Made commits every 100 records: also no effect. > I have also played around with postgresql.conf but also this had no real > effect (which is actually not surprising considering the small size of the > database). > > At this stage the who database has a size of around 1GB. > > I am using pg 9.4 > > any idea of what might be going on? Hello. Just a couple of questions... You talk about two tables; have you also dropped FKs (you only mention indices and PK)? What SQL do you use for inserting the data: * one INSERT per row with autocommit * one INSERT per row inside BEGIN...COMMIT * one INSERT per bulk (20 000 rows) * one COPY per bulk (20 000 rows) ? Is the loading of data the only activity on the server? See also: http://www.postgresql.org/docs/9.4/static/populate.html HTH, Ladislav Lenart -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
