Fix btmarkpos/btrestrpos array key wraparound bug. nbtree's mark/restore processing failed to correctly handle an edge case involving array key advancement and related search-type scan key state. Scans with ScalarArrayScalarArrayOpExpr quals requiring mark/restore processing (for a merge join) could incorrectly conclude that an affected array/scan key must not have advanced during the time between marking and restoring the scan's position.
As a result of all this, array key handling within btrestrpos could skip a required call to _bt_preprocess_keys(). This confusion allowed later primitive index scans to overlook tuples matching the true current array keys. The scan's search-type scan keys would still have spurious values corresponding to the final array element(s) -- not values matching the first/now-current array element(s). To fix, remember that "array key wraparound" has taken place during the ongoing btrescan in a flag variable stored in the scan's state, and use that information at the point where btrestrpos decides if another call to _bt_preprocess_keys is required. Oversight in commit 70bc5833, which taught nbtree to handle array keys during mark/restore processing, but missed this subtlety. That commit was itself a bug fix for an issue in commit 9e8da0f7, which taught nbtree to handle ScalarArrayOpExpr quals natively. Author: Peter Geoghegan <p...@bowt.ie> Discussion: https://postgr.es/m/cah2-wzkgp3ddrjxw6dgjcxo-cu-dkrvjev_arkp2ctbjatd...@mail.gmail.com Backpatch: 11- (all supported branches). Branch ------ REL_11_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/7c07305e6f025a97732adb01ca6fcb499655a886 Modified Files -------------- src/backend/access/nbtree/nbtree.c | 1 + src/backend/access/nbtree/nbtutils.c | 17 ++++++++++++++++- src/include/access/nbtree.h | 4 +++- 3 files changed, 20 insertions(+), 2 deletions(-)
