Run https://github.com/n-st/nench and benchmark the underlying vps first.
On Tue 29 Jan, 2019, 11:59 PM Bob Jolliffe <bobjolli...@gmail.com wrote: > The following is output from analyzing a simple query on a table of > 13436 rows on postgresql 10, ubuntu 18.04. > > explain analyze select * from chart order by name; > QUERY PLAN > > ----------------------------------------------------------------------------------------------------------------- > Sort (cost=1470.65..1504.24 rows=13436 width=725) (actual > time=224340.949..224343.499 rows=13436 loops=1) > Sort Key: name > Sort Method: quicksort Memory: 4977kB > -> Seq Scan on chart (cost=0.00..549.36 rows=13436 width=725) > (actual time=0.015..1.395 rows=13436 loops=1) > Planning time: 0.865 ms > Execution time: 224344.281 ms > (6 rows) > > The planner has predictably done a sequential scan followed by a sort. > Though it might have wished it hadn't and just used the index (there > is an index on name). The sort is taking a mind boggling 224 seconds, > nearly 2 minutes. > > This is on a cloud vps server. > > Interesting when I run the same query on my laptop it completes in > well under one second. > > I wonder what can cause such a massive discrepancy in the sort time. > Can it be that the VPS server has heavily over committed CPU. Note I > have tried this with 2 different company's servers with similar > results. > > I am baffled. The sort seems to be all done in memory (only 5MB). > Tested when nothing else was going on at the time. I can expect some > difference between the VPS and my laptop, but almost 1000x seems odd. > The CPUs are different but not that different. > > Any theories? > > Regards > Bob > >
