txn performance penalty

[Matthias Andree]

Greg Louis <glouis at dynamicro.on.ca> writes:

> Calendar time, on an otherwise idle machine with 512Mb RAM and 1Gb
> swap, to process 545 spam starting after cold boot (memory is clear):
>
> 0.92.8: 51 seconds
> 0.93.1 with defaults: 489 seconds
> 0.93.1 with DB_TXN_NOT_DURABLE: 492 seconds
>
> This was with db-4.2.52.  Processing involved scoring each message
> individually (with formail) and then scoring the same mbox with a
> single bogofilter run (-vM).  The idea is to scan the spams and
> register any false negatives, then rescan to check the result; but in
> these runs there were no fn and so no messages were registered.

I have just fed a large mailbox (1,050 messages) through bogofilter with
formail -ds bogofilter <mbox, 

0.93.1 took 28 s with default settings
   CVS took 22 s with default settings
   CVS took 15 s with --disable-transactions

(arithmetic average of three runs with warm caches)

I see a high system load (about half) during this test, in contrast, a
bulk score of the mbox takes 6 s with 0.93.1 and 4 s with CVS and has
virtually no system load, just user.

Linux 2.6.9, reiserfs, SYM53C8XX adaptor, Fujitsu MAH3182MP, BDB 4.2.52.2

-- 
Matthias Andree