statistics buffer is full

Hi,

just wanted to share some experience with the curious log message:
"statistics buffer is full".

Some time ago we suffered from bad performance on our database server.
We were running 7.4.x. I saw this strange log message and Tom told me a
way to raise this specific buffer. After raising it the box worked fine.

Now we are running 7.4.6 and I still have to patch the source, as I had
to do with all 7.4.x versions.

See attached patch for details. We began raising from 1024 to 2048 then
to 4096. After a while the messages appeared again and now we are at
16384 and the messages have gone again.

Tom: Do you know of any other bad impact this raising might have?

All: If you suffer from bad performance, check your logs and raise this
buffer.

Our specs:

Debian Woody, Kernel 2.6
Postgresql 7.4.6
Dual Xeon 3.2 with HT enabled
Mylex eXtremeRAID 2000 with 4 drives RAID 10

Regards,
Bjoern