From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 4 Aug 2022 18:10:06 +0000 (-0400)
Subject: Add CHECK_FOR_INTERRUPTS in ExecInsert's speculative insertion loop.
X-Git-Tag: REL_10_22~11
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=138213684ad44449449274522ab8fcf119cf848b;p=thirdparty%2Fpostgresql.git

Add CHECK_FOR_INTERRUPTS in ExecInsert's speculative insertion loop.

Ordinarily the functions called in this loop ought to have plenty
of CFIs themselves; but we've now seen a case where no such CFI is
reached, making the loop uninterruptible.  Even though that's from
a recently-introduced bug, it seems prudent to install a CFI at
the loop level in all branches.

Per discussion of bug #17558 from Andrew Kesper (an actual fix for
that bug will follow).

Discussion: https://postgr.es/m/17558-3f6599ffcf52fd4a@postgresql.org
---

diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 54bb2cb5723..23b22385591 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -412,9 +412,11 @@ ExecInsert(ModifyTableState *mtstate,
 			 *
 			 * We loop back here if we find a conflict below, either during
 			 * the pre-check, or when we re-check after inserting the tuple
-			 * speculatively.
+			 * speculatively.  Better allow interrupts in case some bug makes
+			 * this an infinite loop.
 			 */
 	vlock:
+			CHECK_FOR_INTERRUPTS();
 			specConflict = false;
 			if (!ExecCheckIndexConstraints(slot, estate, &conflictTid,
 										   arbiterIndexes))