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We just moved a large production instance of ours from
Oracle to Postgres 8.0.3 on linux. When running on Oracle the machine
hummed along using about 5% of the CPU easily handling the fairly constant load,
after moving the data to Postgres the machine was pretty much maxed out on CPU
and could no longer keep up with the transaction volume. On a hunch I
switched the jdbc driver to using the V2 protocol and the load on the machine
dropped down to what it was when using Oracle and everything was fine. Now obviously I have found a work around for the performance
problem, but I really don’t want to rely on using the V2 protocol
forever, and don’t want to have to recommend to our customers that they
need to run with the V2 protocol. So I would like to resolve the problem
and be able to move back to a default configuration with the V3 protocol and
the benefits thereof. The problem is that I don’t really know where to begin
to debug a problem like this. In development environments and testing
environments we have not seen performance problems with the V3 protocol in the
jdbc driver. But they don’t come close to approaching the
transaction volume of this production instance. What I see when running the V3 protocol under ‘top’
is that the postgres processes are routinely using 15% or more of the CPU each,
when running the V2 protocol they use more like 0.3%. Does anyone have any suggestions on an approach to debug a
problem like this? Thanks, --Barry |
- [PERFORM] Performance problem using V3 protocol in jdbc driver Barry Lind
