> 13 авг. 2019 г., в 20:30, Peter Geoghegan <p...@bowt.ie> написал(а): > > That's one possibility. When I first designed amcheck it was important > to be conservative, so I invented a general rule about never acquiring > multiple buffer locks at once. I still think that that was the correct > decision for the bt_downlink_check() check (the main extra > bt_index_parent_check() check), but I think that you're right about > retrying to verify the sibling links when bt_index_check() is called > from SQL. > > nbtree will often "couple" buffer locks on the leaf level; it will > acquire a lock on a leaf page, and not release that lock until it has > also acquired a lock on the right sibling page (I'm mostly thinking of > _bt_stepright()). I am in favor of a patch that makes amcheck perform > sibling link verification within bt_index_check(), by retrying while > pessimistically coupling buffer locks. (Though I think that that > should just happen on the leaf level. We should not try to be too > clever about ignorable/half-dead/deleted pages, to be conservative.)
PFA V1 of this check retry. Best regards, Andrey Borodin.
0001-In-amcheck-nbtree-do-rightlink-verification-with-loc.patch
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