Don't call PageGetSpecialPointer() on page until it's been initialized.
After calling XLogInitBufferForRedo(), the page might be all-zeros if it was
not in page cache already. btree_xlog_unlink_page initialized the page
correctly, but it called PageGetSpecialPointer before initializing it, which
would lead to a corrupt page at WAL replay, if the unlinked page is not in
page cache.
Backpatch to 9.4, the bug came with the rewrite of B-tree page deletion.
Branch
------
master
Details
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http://git.postgresql.org/pg/commitdiff/fdf28853ae6a397497b79fea69f89f4f7b9aa991
Modified Files
--------------
src/backend/access/nbtree/nbtxlog.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)