05.07.2011 10:23, Paul Reeves wrote: > > All tests are run from a freshly restored backup containing 100,000 rows in > the test table. Forced Writes are ON and hard drive disc caches are disabled. > Firebird 2.1.4 is the server.
FW and HDD settings don't affect the page I/O stats. > The attachment only executes a single statement so the difference between page > writes derived from the perf.h api and the mon$io page writes should be > statistically insignificant, but in all cases the mon$io stat should be > slightly larger due to the extra book-keeping for closing the isql txns. These observations are true only for the statistics reported for stat_group = 0, as isql measures the database-wise statistics. > The figures do not match up. Here are the results: > > PLATFORM PAGE_SIZE PERF PAGE_WRI MON$IO PAGE_WRI > ========= ========= ============= =============== > Linux x64 4096 70,139 33,495 > W2K3 x64 4096 69,948 33,138 > > Linux x64 8192 40,710 41,820 > W2K3 x64 8192 43,945 44,118 > > Linux x64 16384 35,912 36,456 > W2K3 x64 16384 39,056 38,874 > > > We can see that the figures for Windows and Linux are broadly similar. > > 1/ Why are the perf page writes double the mon$io page writes for the 4K page > size? > > 2/ Why is the perf page writes value slightly greater than the mon$io page > writes for the 16K page size under windows? > > 3/ Why are the mon$io page writes greater for 8K than 4K? It's hard to guess without having the test at hands. Perhaps it's related to the background I/O. Could you share the test case? > After running these tests I then took a look at the MON$IO_STATS for the last > database run (Windows 16K page size). One would expect to see the page write > stats for stat_group 0 to be around 39,000. However, I'm only seeing 49 > page_writes. I suppose that you looked at the database stats in the new connection (after the last isql run has exited), so the stats were reset. Dmitry ------------------------------------------------------------------------------ All of the data generated in your IT infrastructure is seriously valuable. Why? It contains a definitive record of application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-d2d-c2 Firebird-Devel mailing list, web interface at https://lists.sourceforge.net/lists/listinfo/firebird-devel
