[ZODB-Dev] Re: What makes the ZODB slow?

[Dieter Maurer]

Roché Compaan wrote at 2006-6-23 19:04 +0200:
> ...
>In a test where one commits an instance of a Persistent
>subclass that have only 2 string attributes, 300 objects per second are
>created on average. Writing the exact same strings to a two column table
>in an RDBMS, yields more than 3000 records per second including indexing
>of the data.

This largely is the fault of "fsync". It tends to be extremely
slow on many platforms. There was an interesting poll for
"fsync" timings in this mailing list (about 1 year or so ago).


The ZODB uses "fsync" once per transaction. Apparently,
many relational databases do it less often and therefore
achieve a much higher transaction rate.



-- 
Dieter