| From: | Joe Conway <mail(at)joeconway(dot)com> |
|---|---|
| To: | "Nigel J(dot) Andrews" <nandrews(at)investsystems(dot)co(dot)uk> |
| Cc: | Shridhar Daithankar <shridhar_daithankar(at)persistent(dot)co(dot)in>, Pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: Improving speed of copy |
| Date: | 2002-09-20 18:28:15 |
| Message-ID: | 3D8B68BF.1030700@joeconway.com |
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| Lists: | pgsql-hackers |
Nigel J. Andrews wrote:
> On Fri, 20 Sep 2002, Shridhar Daithankar wrote:
>
>>In select test where approx. 15 rows where reported with query on index field,
>>mysql took 14 sec. and psotgresql took 17.5 sec. Not bad but other issues
>>eclipse the result..
>
> I don't know about anyone else but I find this aspect strange. That's 1 second
> (approx.) per row retrieved. That is pretty dire for an index scan. The
> data/index must be very non unique.
>
Yeah, I'd agree that is strange. Can we see EXPLAIN ANALYZE for that query.
Also, in one of your ealier posts you mentioned a slowdown after raising
shared buffers from the default 64 to 30000. You might have driven the machine
into swapping. Maybe try something more like 10000 - 15000.
HTH,
Joe
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