Jeff, Your conclusions sound great - can you perhaps put the timings in a column in your table so we can confirm them?
- Luke On 4/2/07 4:14 PM, "Jeff Davis" <[EMAIL PROTECTED]> wrote: > I posted some fairly detailed benchmark results for my Synchronized Scan > patch and it's interactions with Simon Riggs' Recycle Buffers patch > here: > > http://j-davis.com/postgresql/patch15-results.html > > The results are in the form of log files that contain lots of useful > debugging info: > > * log_executor_stats is on (meaning it shows cache hit rate) > * the pid, timestamp, and pagenumber being retrieved (for every 5k pages > read) > * the duration of each scan > > The results are very positive and quite conclusive. > > However, the "sync_seqscan_offset" aspect of my patch, which attempts to > use pages that were cached before the scan began, did not show a lot of > promise. That aspect of my patch may end up being cut. > > The primary aspect of my patch, the Synchronized Scanning, performed > great though. Even the CFQ scheduler, that does not appear to properly > read ahead, performed substantially better than plain 8.2.3. And even > better, Simon's patch didn't seem to hurt Synchronized Scans at all. > > Out of the 36 runs I did, a couple appear anomalous. I will retest those > soon. > > Note: I posted the versions of the patches that I used for the tests on > the page above. The version of Simon's patch that I used did not apply > cleanly to 8.2.3, but the only problem appeared to be in copy.c, so I > went ahead with the tests. If this somehow compromised the patch, then > let me know. > > Regards, > Jeff Davis > > > > > ---------------------------(end of broadcast)--------------------------- > TIP 2: Don't 'kill -9' the postmaster > ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
