Re: [GENERAL] Longer and longer updates

* Steve Wilmarth <swilmarth(at)eknow(dot)com> [010205 12:50] wrote:
>
> Hi all-
>
> In doing some stress testing I noticed that our database was slowing
> down significantly after doing the same update repeatedly on a table
> with no indexes, so I tried this:
>
> 1) created an empty database
>
> 2) made a simple table with a single row:
>
> create table test (key int4, data int4);
> insert into test values (1, 0);
>
> 3) executed this statement tons of times:
>
> update test set data=1234 where key=1
>
> Here are the results -- it's pretty discouraging, I hope I'm making some
> simple mistake, or maybe this is expected behavior for some reason?
>
> After this many updates ...it took this long for 1000 more updates
> ----------------------- ------------------------------------------
> 0 10880 ms
> 5,000 10549 ms
> 10,000 17380 ms
> 15,000 20040 ms
> 20,000 20060 ms
> 25,000 20589 ms
> 30,000 30749 ms
> 35,000 30350 ms
> 40,000 30910 ms
> 45,000 37570 ms
> 50,000 40379 ms
>
> This seems to be independent of starting and stopping my client and the
> postmaster, running vacuum, praying, etc. I'm on RedHat6.2
> running with the 7.1beta4 rpms.
>
> Anyone know what's going on here?

You're not vacuuming.

--
-Alfred Perlstein - [bright(at)wintelcom(dot)net|alfred(at)freebsd(dot)org]
"I have the heart of a child; I keep it in a jar on my desk."