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