> > > Early performance tests on my laptop suggest it's about 8% > > > faster for writing when both the FS and PostgreSQL use 16K > > > blocks. > > > > BTW, I don't really believe that one set of tests, conducted on > > one single machine, are anywhere near enough justification for > > changing this value. Especially not if it's a laptop rather than > > a typical server configuration. You've got considerably less I/O > > bandwidth in proportion to CPU horsepower than a server. Why is > > that an issue? Well, a larger block size will substantially > > increase our WAL overhead (because we tend to dump whole blocks > > into WAL at the slightest provocation) and on slower machines the > > CRC64 calculations involved in WAL entries are a significant cost. > > On a machine with less CPU and more disk horsepower than you > > tested, the tradeoffs could be a lot different. > > Sean, can we get a copy of your test set? And any scripts that you > have for running the tests?
Unfortunately not, my tests were simply re-initdb'ing and loading in my schema. I have some read tests I'm going to perform here in a bit, but I'm waiting for kde to finish compiling before I start testing. I have another tests machine that I'm going to task with comparing 16K and 8K blocks. It's not SCSI, but I don't have any available machines that I can newfs + reinstall PostgreSQL on. I was thinking about running the regression tests 10x ... -sc -- Sean Chittenden ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster
