Re: [PERFORM] Slow query with big tables

2016-08-27 Thread Jeff Janes
On Fri, Aug 26, 2016 at 6:17 AM, Tommi K wrote: > Hello, > thanks for the response. I did not get the response to my email even > though I am subscribed to the pgsql-performance mail list. Let's hope that > I get the next one :) > > Increasing work_mem did not have great impact on the performance

Re: [PERFORM] Slow query with big tables

2016-08-27 Thread Jeff Janes
On Sat, Aug 27, 2016 at 7:13 AM, Craig James wrote: > On Fri, Aug 26, 2016 at 9:11 PM, Jim Nasby > wrote: > >> On 8/26/16 3:26 PM, Mike Sofen wrote: >> >>> Is there way to keep query time constant as the database size grows. >>> >> >> No. More data == more time. Unless you find a way to break th

Re: [PERFORM] Slow query with big tables

2016-08-27 Thread Tom Lane
Craig James writes: > Straight hash-table indexes (which Postgres doesn't use) have O(1) access > time. The amount of data has no effect on the access time. This is wishful thinking --- once you have enough data, O(1) goes out the window. For example, a hash index is certainly not going to conti

Re: [PERFORM] Slow query with big tables

2016-08-27 Thread Craig James
On Fri, Aug 26, 2016 at 9:11 PM, Jim Nasby wrote: > On 8/26/16 3:26 PM, Mike Sofen wrote: > >> Is there way to keep query time constant as the database size grows. >> > > No. More data == more time. Unless you find a way to break the laws of > physics. > Straight hash-table indexes (which Postgr