On 4/19/07, Heikki Linnakangas <heikki(at)enterprisedb(dot)com> wrote:
> What's the purpose of the "HeapScanHintPagePrune" mechanism in index
> builds? I lost track of the discussion on create index, is the it
> necessary for correctness?
Its not required strictly for correctness, but it helps us prune the
while index building. During index build, if we skip a tuple which is
RECENTLY_DEAD, existing transactions can not use the index for queries.
Pruning the HOT-chains reduces the possibility of finding such tuples
while building the index.
A comment in IndexBuildHeapScan explaining
> why it's done would be nice.
I would do that.
In any case a PG_TRY/CATCH block should be
> used to make sure it's turned off after an unsuccessful index build.
Oh thanks. Would do that too
I would wait for other review comments before submitting a fresh patch.
I hope thats ok.
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