On Tue, 19 Mar 2019 16:03:21 +0000 "Leyne, Sean" <s...@broadviewsoftware.com> wrote:
> > > There is very little documentation available on the Classic lock > > > manager related settings, which is why I ask the question in this > > > forum. Interested in v2. 5 limitations, but details/differences > > > for other versions would be appreciated. > > > > I assume you mean hash table slots: > > > > const SLONG HASH_MAX_SLOTS = 65521; > > That was what I was looking for? > > Is there any reason why for x64 builds that number could not be > increased? > As I understand it, a high number of slots will reduce the queue lengths at the cost of checking a lot of empty slots. Like everything else, there is a sweet spot. In your case the queues are typically empty so you could reduce the number substantially and still see an improvement in performance. I did some tests a while back which showed that hash slots greater than around 8000 actually decreased performance. But that was with the tpc-c benchmark. The results were consistent across architectures, with 1009 being slightly behind 31991, which itself was behind 16001. But in all cases 8009 was the winner. I didn't go deeper - it may be that the real sweet spot is between, say, 6,000 and 12,000, but again, it may also be database/application specific. But I would start with 8009 and maybe go upward slowly, rather than jumping to around 64K. Paul -- Paul Reeves http://www.ibphoenix.com Supporting users of Firebird Firebird-Devel mailing list, web interface at https://lists.sourceforge.net/lists/listinfo/firebird-devel
