On Fri, Nov 2, 2018 at 5:00 PM Peter Geoghegan <p...@bowt.ie> wrote: > I had the opportunity to discuss this patch at length with Heikki > during pgConf.EU.
> The DESC heap TID sort order thing probably needs to go. I'll probably > have to go fix the regression test failures that occur when ASC heap > TID order is used. I've found that TPC-C testing with ASC heap TID order fixes the regression that I've been concerned about these past few weeks. Making this change leaves the patch a little bit faster than the master branch for TPC-C, while still leaving TPC-C indexes about as small as they were with v6 of the patch (i.e. much smaller). I now get about a 1% improvement in transaction throughput, an improvement that seems fairly consistent. It seems likely that the next revision of the patch series will be an unambiguous across the board win for performance. I think that I come out ahead with ASC heap TID order because that has the effect of reducing the volume of WAL generated by page splits. Page splits are already optimized for splitting right, not left. I should thank Heikki for pointing me in the right direction here. -- Peter Geoghegan
