| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com> |
| Cc: | Tim Dudgeon <tdudgeon(dot)ml(at)gmail(dot)com>, pgsql-sql(at)postgresql(dot)org, pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: [SQL] querying with index on jsonb slower than standard column. Why? |
| Date: | 2014-12-08 21:22:56 |
| Message-ID: | 4746.1418073776@sss.pgh.pa.us |
| Views: | Whole Thread | Raw Message | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-performance pgsql-sql |
Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com> writes:
> I redid the test on my 32-bit machine, setting work_mem=16MB, and I got
> comparable results to what I saw on the 64-bit machine. So, what I am
> still am puzzled by is why work_mem seems to make the two paths
> equivalent in time?:
If work_mem is large enough that we never have to go through
tbm_lossify(), then the recheck condition will never be executed,
so its speed doesn't matter.
(So the near-term workaround for Tim is to raise work_mem when
working with tables of this size.)
regards, tom lane
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Adrian Klaver | 2014-12-08 21:34:38 | Re: querying with index on jsonb slower than standard column. Why? |
| Previous Message | Adrian Klaver | 2014-12-08 21:14:48 | Re: querying with index on jsonb slower than standard column. Why? |
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Adrian Klaver | 2014-12-08 21:34:38 | Re: querying with index on jsonb slower than standard column. Why? |
| Previous Message | Adrian Klaver | 2014-12-08 21:14:48 | Re: querying with index on jsonb slower than standard column. Why? |