From 480bc6e3ed3a5719cdec076d4943b119890e8171 Mon Sep 17 00:00:00 2001 From: Peter Geoghegan Date: Mon, 22 Apr 2024 13:58:06 -0400 Subject: [PATCH] Remove unneeded nbtree array preprocessing assert. Certain cases involving the use of cursors had assertion failures within _bt_preprocess_keys's recently added no-op return path. The assertion in question made the faulty assumption that a second or third call to _bt_preprocess_keys (within the same btrescan) could only happen when another scheduled primitive index scan was just about to begin. It would be possible to address the problem by only allowing scans that have array keys to take the new no-op path, forcing affected cases to perform redundant preprocessing work. It seems simpler to just remove the assertion, and reframe the no-op path as a more general mechanism. Take this simpler approach. The important underlying principle is that we only need to perform preprocessing once per btrescan (at most). This is expected regardless of whether or not the scan happens to have array keys. Oversight in commit 1b134ca5, which enhanced nbtree ScalarArrayOp execution. Reported-By: Alexander Lakhin Discussion: https://postgr.es/m/ef0f7c8b-a6fa-362e-6fd6-054950f947ca@gmail.com --- src/backend/access/nbtree/nbtutils.c | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) diff --git a/src/backend/access/nbtree/nbtutils.c b/src/backend/access/nbtree/nbtutils.c index 8381027f4e..05f0d23dc0 100644 --- a/src/backend/access/nbtree/nbtutils.c +++ b/src/backend/access/nbtree/nbtutils.c @@ -2572,19 +2572,16 @@ _bt_preprocess_keys(IndexScanDesc scan) int *keyDataMap = NULL; int arrayidx = 0; - /* - * We're called at the start of each primitive index scan during scans - * that use equality array keys. We can just reuse the scan keys that - * were output at the start of the scan's first primitive index scan. - */ if (so->numberOfKeys > 0) { /* - * An earlier call to _bt_advance_array_keys already set everything up - * already. Just assert that the scan's existing output scan keys are - * consistent with its current array elements. + * Only need to do preprocessing once per btrescan, at most. All + * calls after the first are handled as no-ops. + * + * If there are array scan keys in so->keyData[], then the now-current + * array elements must already be present in each array's scan key. + * Verify that that happened using an assertion. */ - Assert(so->numArrayKeys); Assert(_bt_verify_keys_with_arraykeys(scan)); return; }