On 4/19/07, Heikki Linnakangas <[EMAIL PROTECTED]> 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.