HOT add-on patch

Hi All,

This patch is an add-on patch the version 15 posted earlier and
should be applied on top of version 15. The following review items
has been fixed:

- Fix the pruning code to prune all tuples upto and including the
latest DEAD tuple in the chain.

- Removed the heap tuple freezing changes because they are
no longer required because of changes to the pruning code

- Removed the HeapTupleSatisfiesAbort() code. We now collect
all DEAD heap-only tuples while scanning the page. A separate
bitmap is used to avoid duplicate entries in the deadtups array.
This is required because a DEAD HOT tuple may be scanned twice,
once while traversing the chain and then directly.

- A little improvement to the WAL logging in heap_page_prune_defrag().
Earlier we were logging two WAL records, now we do that only once

- The autoanalyze code now treats redirect dead line pointers as dead
rows.

Thanks,
Pavan

--
Pavan Deolasee
EnterpriseDB http://www.enterprisedb.com