From a846ee9854ee9994935d697e1f9c2a0d70f328f1 Mon Sep 17 00:00:00 2001 From: Heikki Linnakangas Date: Mon, 5 Oct 2026 13:32:00 +0300 Subject: [PATCH] amcheck: Allow interrupting the child-level rightlink walk bt_child_highkey_check() walks right along the child level following btpo_next links, reading a page on each iteration, but its loop lacked a CHECK_FOR_INTERRUPTS(). Every other page-traversal loop in verify_nbtree.c already has one. The loop's existing checks do not guarantee a timely exit on a corrupt index. The in-loop cycle check only fires when a rightlink points back through the block the walk started from, or to a page whose btpo_prev points to itself, so a cycle further downstream can go undetected -- for example a run of pages all flagged P_INCOMPLETE_SPLIT, which skips both the high-key comparison and bt_downlink_missing_check() and so never reaches an error. Such an index, or simply a very long rightlink chain, makes the walk effectively uninterruptible. Since amcheck exists to be run against possibly-corrupt indexes, make this walk respond to query cancellation and shutdown requests like the sibling loops do. Author: Paul Kim Reviewed-by: shihao zhong Discussion: https://www.postgresql.org/message-id/20260717151437.10713-1-mok03127@gmail.com --- contrib/amcheck/verify_nbtree.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/contrib/amcheck/verify_nbtree.c b/contrib/amcheck/verify_nbtree.c index c5e1f901098..455eb90f38c 100644 --- a/contrib/amcheck/verify_nbtree.c +++ b/contrib/amcheck/verify_nbtree.c @@ -2191,6 +2191,8 @@ bt_child_highkey_check(BtreeCheckState *state, /* Move to the right on the child level */ while (true) { + CHECK_FOR_INTERRUPTS(); + /* * Did we traverse the whole tree level and this is check for pages to * the right of rightmost downlink?