Tom Lane wrote:
"Pavan Deolasee" <[EMAIL PROTECTED]> writes:
On Wed, Mar 5, 2008 at 9:29 PM, Tom Lane <[EMAIL PROTECTED]> wrote:
[ thinks some more... ] I guess we could use a flag array dimensioned
MaxHeapTuplesPerPage to mark already-processed tuples, so that you
wouldn't need to search the existing arrays but just index into the flag
array with the tuple's offsetnumber.
We can actually combine this and the page copying ideas. Instead of copying
the entire page, we can just copy the line pointers array and work on the copy.
I think that just makes things more complex and fragile. I like
Heikki's idea, in part because it makes the normal path and the WAL
recovery path guaranteed to work alike. I'll attach my work-in-progress
patch for this --- it doesn't do anything about the invalidation
semantics problem but it does fix the critical-section-too-big problem.
FWIW, the patch looks fine to me. By inspection; I didn't test it.
I'm glad we got away with a single "marked" array. I was afraid we would
need to consult the unused/redirected/dead arrays separately.
Do you have a plan for the invalidation problem? I think we could just
not remove the redirection line pointers in catalog tables.
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
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