| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Heikki Linnakangas <hlinnaka(at)iki(dot)fi> |
| Cc: | pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>, Peter Geoghegan <pg(at)heroku(dot)com> |
| Subject: | Re: Tuplesort merge pre-reading |
| Date: | 2017-04-14 04:57:20 |
| Message-ID: | 22681.1492145840@sss.pgh.pa.us |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
I wrote:
> Heikki Linnakangas <hlinnaka(at)iki(dot)fi> writes:
>> I'm talking about the code that reads a bunch of from each tape, loading
>> them into the memtuples array. That code was added by Tom Lane, back in
>> 1999:
>> So apparently there was a benefit back then, but is it still worthwhile?
> I'm fairly sure that the point was exactly what it said, ie improve
> locality of access within the temp file by sequentially reading as many
> tuples in a row as we could, rather than grabbing one here and one there.
[ blink... ] Somehow, my mail reader popped up a message from 2016
as current, and I spent some time researching and answering it without
noticing the message date.
Never mind, nothing to see here ...
regards, tom lane
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Amit Langote | 2017-04-14 05:10:12 | Re: pg_dump emits ALTER TABLE ONLY partitioned_table |
| Previous Message | Tom Lane | 2017-04-14 04:51:15 | Re: Tuplesort merge pre-reading |