Re: Performance while loading data and indexing

On 26 Sep 2002 at 19:17, Justin Clift wrote:
> Shridhar Daithankar wrote:
> <snip>
> > 3) Any suggsestions for runtime as data load and query will be going in
> > parallel.
>
> That sounds unusual. From reading this, it *sounds* like you'll be
> running queries against an incomplete dataset, or maybe just running the
> queries that affect the tables loaded thus far (during the initial
> load).

That's correct. Load the data so far and keep inserting data as and when it
generates.

They don't mind running against data so far. It's not very accurate stuff
IMO...

> > fsync=true (Sad but true. Left untouched.. Will that make a difference on
> > SCSI?)
>
> Definitely. Have directly measured a ~ 2x tps throughput increase on
> FreeBSD when leaving fsync off whilst performance measuring stuff
> recently (PG 7.2.2). Like anything it'll depend on workload, phase of
> moon, etc, but it's a decent indicator.

I didn't know even that matters with SCSI..Will check out..

> fsync = off would help during the data load, but not a good idea if
> you're going to be running queries against it at the same time.

That's OK for the reasons mentioned above. It wouldn't be out of place to
expect a UPS to such an installation...

Bye
Shridhar

--
Hoare's Law of Large Problems: Inside every large problem is a small problem
struggling to get out.