On Fri, 2005-12-02 at 17:45 -0500, Tom Lane wrote: > Simon Riggs <[EMAIL PROTECTED]> writes: > > CREATE INDEX uses SnapshotAny, so the scan that feeds the build could > > easily include rows added after the CREATE INDEX started. When the scan > > was exhausted we could mark that last TID and return to it after the > > sort/build. > > And do what? This has nothing to do with the fundamental problem of > never being able to catch up unless you can upgrade your lock to exclude > writes. What's worse, once you have excluded writes you have to rescan > the entire table to be sure you haven't missed anything. So in the > scenarios where this whole thing is actually interesting, ie enormous > tables, you're still talking about a fairly long interval with writes > locked out. Maybe not as long as a complete REINDEX, but long.
Those are technical difficulties that I believe can be solved. Greg was right: online index builds are very useful (for us). Best Regards, Simon Riggs ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
