On Mon, 2006-06-19 at 15:04 -0400, Greg Stark wrote: > > We fsync the xlog at transaction commit, so only the leading edge needs > > to be synced - would the call help there? Presumably the OS can already > > locate all blocks associated with a particular file fairly quickly > > without doing a full cache scan. > > Well in theory the transaction being committed isn't necessarily the "leading > edge", there could be more work from other transactions since the last work > this transaction actually did.
Near enough. > > Other files are fsynced at checkpoint - always all dirty blocks in the > > whole file. > > Well couldn't it be useful for checkpoints if it there was some way to know > which buffers had been touched since the last checkpoint? There could be a lot > of buffers dirtied since the checkpoint began and those don't really need to > be synced do they? Qingqing had a proposal for something like that, but seemed not worth it after analysis. -- Simon Riggs EnterpriseDB http://www.enterprisedb.com ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
