Friday, October 12, 2012

How 3.6 nearly broke PostgreSQL (link)

In mid-September, the 3.6 kernel appeared to be stabilizing nicely. Most of the known regressions had been fixed, the patch volume was dropping, and Linus was relatively happy. Then Nikolay Ulyanitsky showed up with a problem: the pgbench PostgreSQL benchmark ran 20% slower than under 3.5. The resulting discussion shows just how hard scalability can be on contemporary hardware and how hard scheduling can be in general.