[ZODB-Dev] Using zodb and blobs

[Nitro]

Am 14.04.2010, 04:39 Uhr, schrieb Tim Peters <tim.peters at gmail.com>:

> [Nitro]
>> ...
>> I wonder if _commit is really *that* slow
>
> Six years ago I timed factor-of-100 speed differences due to using MS
> _commit() on WinXP at the time:
>
>     https://mail.zope.org/pipermail/zodb-dev/2004-July/007720.html
>
>> or if there's another (faster) function which can be called...
>
> No MS function that does the same thing.

Seems like ZODB has a long history of discussions on this matter:

http://www.mail-archive.com/zodb-dev@zope.org/msg01874.html

There's even a proposal for improvement in that thread, also on the wiki:

http://wiki.zope.org/ZODB/FsyncBehaviourSetting

What I don't really get is why you should never use "None" on windows. As  
far as I can judge from the various transaction rates in the thread Tim  
mentioned, fsync is just a no-op on linux anyways (depending on the  
specific file system of course).

I am almost tempted to do

os.fsync = lambda fd: 0

and rely on yesterday's backup. 0.49 j/k.

Postgres has something similar as the proposal suggested:

http://www.postgresql.org/docs/8.1/interactive/runtime-config-wal.html

-Matthias