Tom Lane wrote:


I could certainly do some testing if you want to see how DBT-2 does.
Just tell me what to do. ;)

Just do some runs that are identical except for the wal_sync_method
setting. Note that this should not have any impact on SELECT
performance, only insert/update/delete performance.

I've made a test run that compares fsync and fdatasync: The performance was identical:
- with fdatasync:

- with fsync:

I don't understand why. Mark - is there a battery backed write cache in the raid controller, or something similar that might skew the results? The test generates quite a lot of wal traffic - around 1.5 MB/sec. Perhaps the writes are so large that the added overhead of syncing the inode is not noticable?
Is the pg_xlog directory on a seperate drive?

Btw, it's possible to request such tests through the web-interface, see


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