Simon Riggs wrote:
> During recent tuning of the TPC-C workload, I produced the following
> patch to force COPY to leave some space in each data block when it loads
> data into heap relations.
I can't get too excited about incorporating changes designed solely to
improve performance for the workload of a specific database benchmark.
If the change has merit in some plausible "real world" situations, so be
it -- but if not, I don't see the point.
> Each UPDATE tries to insert a new row version. The blocks are all full,
> so each UPDATE causes this activity:
> read block, decide cannot insert, unlock block
> extend relation by 1 block
> relock first block, lock new block
> insert row into new block
> After the patch, most UPDATEs cause only a single block access/update,
> excluding the index effects.
Did you do any benchmarks to measure the performance of the patch?
-Neil
