On Fri, Dec 23, 2011 at 12:42 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Robert Haas <robertmh...@gmail.com> writes: >> An obvious problem is that, if the abort rate is significantly >> different from zero, and especially if the aborts are randomly mixed >> in with commits rather than clustered together in small portions of >> the XID space, the CLOG rollup data would become useless. > > Yeah, I'm afraid that with N large enough to provide useful > acceleration, the cases where you'd actually get a win would be too thin > on the ground to make it worth the trouble.
Well, I don't know: something like pgbench is certainly going to benefit, because all the transactions commit. I suspect that's true for many benchmarks. Whether it's true of real-life workloads is more arguable, of course, but if the benchmarks aren't measuring things that people really do with the database, then why are they designed the way they are? I've certainly written applications that relied on the database for integrity checking, so rollbacks were an expected occurrence, but then again those were very low-velocity systems where there wasn't going to be enough CLOG contention to matter anyway. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers