Re: Optimization for lazy_scan_heap

The following review has been posted through the commitfest application:
make installcheck-world:  tested, passed
Implements feature:       not tested
Spec compliant:           not tested
Documentation:            not tested

Hi,
I haven't tested the performance yet, but the patch itself looks pretty good
and reasonable improvement.
I have a question about removing the comment. It seems to be really tricky
moment. How do we know that all-frozen block hasn't changed since the 
moment we checked it?

-                 * Tricky, tricky.  If this is in aggressive vacuum, the page
-                 * must have been all-frozen at the time we checked whether it
-                 * was skippable, but it might not be any more.  We must be
-                 * careful to count it as a skipped all-frozen page in that
-                 * case, or else we'll think we can't update relfrozenxid and
-                 * relminmxid.  If it's not an aggressive vacuum, we don't
-                 * know whether it was all-frozen, so we have to recheck; but
-                 * in this case an approximate answer is OK.
+                 * We know that there are n_skipped pages by the visibilitymap scan we
+                 * did just before.                 */

I'm going to test the performance this week.
I wonder if you could send a test script or describe the steps to test it?

The new status of this patch is: Waiting on Author