On Thu, Jul 1, 2010 at 10:07 PM, Craig Ringer <cr...@postnewspapers.com.au>wrote:
> On 01/07/10 17:41, Rajesh Kumar Mallah wrote: > > Hi, > > > > this is not really a performance question , sorry if its bit irrelevant > > to be posted here. We have a development environment and we want > > to optimize the non-database parts of the application. The problem is > > that subsequent run of queries are execute very fast and makes the > > performance analysis a trivial problem. We want that the subsequent runs > > of query should take similar times as the first run so that we can work > > on the optimizing the calling patterns to the database. > > You can get rid of PostgreSQL's caches in shared_buffers by restarting > the PostgreSQL server. I don't know if there's any more convenient way. > Alternately, just set a really minimal shared_buffers that's just enough > for your connections so there's not much room for cached data. > > I had set it to 128kb it does not really work , i even tried your next suggestion. I am in virtualized environment particularly OpenVz. where echo 3 > /proc/sys/vm/drop_caches does not work inside the virtual container, i did it in the hardware node but still does not give desired result. regds Rajesh Kumar Mallah. > If you are running a Linux server (as you didn't mention what you're > running on) you can drop the OS disk cache quite easily: > > http://linux-mm.org/Drop_Caches > http://www.linuxinsight.com/proc_sys_vm_drop_caches.html > > AFAIK for most other platforms you have to use a tool that gobbles > memory to force caches out. On Windows, most of those garbage tools that > claim to "free" memory do this - it's about the only time you'd ever > want to use one, since they do such horrid things to performance. > > -- > Craig Ringer >
