Re: Sustained inserts per sec ... ?

From: Simon Riggs <simon(at)2ndquadrant(dot)com>
To: Christopher Petrilli <petrilli(at)gmail(dot)com>
Cc: jd(at)commandprompt(dot)com, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, "Marc G(dot) Fournier" <scrappy(at)postgresql(dot)org>, pgsql-performance(at)postgresql(dot)org
Subject: Re: Sustained inserts per sec ... ?
Date: 2005-04-04 20:58:23
Message-ID: 1112648303.16721.816.camel@localhost.localdomain
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On Mon, 2005-04-04 at 16:18 -0400, Christopher Petrilli wrote:
> On Apr 4, 2005 4:11 PM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
> > > > I'm very interested in the graphs of elapsed time for COPY 500 rows
> > > > against rows inserted. The simplistic inference from those graphs are
> > > > that if you only inserted 5 million rows into each table, rather than 10
> > > > million rows then everything would be much quicker. I hope this doesn't
> > > > work, but could you try that to see if it works? I'd like to rule out a
> > > > function of "number of rows" as an issue, or focus in on it depending
> > > > upon the results.
> >
> > Any chance of running a multiple load of 4 million rows per table,
> > leaving the test running for at least 3 tables worth (12+ M rows)?
>
> As soon as I get done running a test without indexes :-)
>
> > > > Q: Please can you confirm that the discontinuity on the graph at around
> > > > 5000 elapsed seconds matches EXACTLY with the switch from one table to
> > > > another? That is an important point.
> > >
> > > Well, the change over happens at 51593.395205 seconds :-) Here's two
> > > lines from the results with row count and time added:
> > >
> > > 10000000 51584.9818912 8.41331386566
> > > 10000500 51593.395205 0.416964054108
> > >
> My program *SPECIFICALLY* counts to 10M then switches the COPY statement.

> > OK. Please...
> > cd $PGDATA/base/26488263
> > ls -l
>
> [root(at)bigbird base]# cd 26488263/
> [root(at)bigbird 26488263]# ls -l
> total 2003740

> -rw------- 1 pgsql pgsql 1073741824 Apr 4 15:07 26488271
> -rw------- 1 pgsql pgsql 407527424 Apr 4 16:17 26488271.1

Can you do:
select relname from pg_class where relfilenode = 26488271
and confirm that the name is the table you've been loading...

Couldn't see all your indexes... are they still there?

Thanks,

Best Regards, Simon Riggs

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