On Wed, 26 Feb 2020 16:28:38 +0300 Alex Peshkoff via Firebird-devel <firebird-devel@lists.sourceforge.net> wrote:
> On 2020-02-26 15:46, Paul Reeves wrote: > > AFAICT most of the content of that document is rubbish. They have > > certainly skewed our support costs heavily, using the most extreme > > examples. > > It's also unclear what point version of FB3 was used - 3.0.0 or something > newer like 3.0.4. I'm sure they give different scalability results. > > > The tpc-c performance figures look extremely suspect. Does anyone > > seriously do tpc-c testing with 2 warehouses? It doesn't make sense to me. > > > > Looking at the figures for the full table scan it looks as if they have > > created a 16 warehouse database. This will occupy around 1.5 GB of disc > > space and can easily be loaded in memory. This in itself has an impact on > > the quality of the test results. > > > > The InterBase tests were done with journaling and async writes compared to > > Firebird with synchronous writes. We don't know the journalling > > configuration. We also don't know how long the tests were run for. And > > neither do we know anything about the speed and latency of disc > > sub-system. If the run is short then journalling would have minimal > > overhead and InterBase writes would just be cached while Firebird would > > write straight to disk. So basically the comparison would be invalid. > > More realistic performance comparisons would be > > o with journalling off and sync vs sync > > o journalling off and async vs async > > Here I can't agree with you. They compare 2 recommended fail-safe > configurations - IBase with journalling (due to journalling there is no > need to use sync writes) and firebird with sync writes (we have no other > way to be fail-safe). The idea of the failsafe comparison is valid but it depends on how they have configured journalling. Under light load the cost of journalling will have limited impact as it will almost certainly be cached. So it is quite possible to create a test which gives the impression that Firebird is slow in comparison. Which is why I was suggesting other simple comparisons that are more like for like. > What will be very interesting re journalling - compare interbase with > journalling and async writes vs. interbase without journalling and sync > writes. This can give us an idea what effect does journalling give. Agreed - that is also a test that be interesting to carry out. Under a realistic load, of course. 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
