From d7784344917035d197fcc3f66e724f4f28036bf7 Mon Sep 17 00:00:00 2001
From: Zsolt Parragi <zsolt.parragi@percona.com>
Date: Tue, 14 Jul 2026 12:26:12 +0000
Subject: [PATCH] Dump index column statistics for index-backed constraints

dumpIndex emits ALTER INDEX ... SET STATISTICS, but the matching code
was missing from dumpConstraint. Stats targets on exclusion constraint
index expressions were silently lost on dump/restore and pg_upgrade.
Add the same block to dumpConstraint.
---
 src/bin/pg_dump/pg_dump.c        | 41 ++++++++++++++++++++++++++++++++
 src/bin/pg_dump/t/002_pg_dump.pl | 20 ++++++++++++++++
 2 files changed, 61 insertions(+)

diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 4948e6d80c7..0a1423860ca 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -18939,6 +18939,47 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 							  fmtId(indxinfo->dobj.name));
 		}
 
+		/*
+		 * If the index has any statistics on some of its columns, generate
+		 * the associated ALTER INDEX queries.
+		 */
+		if (strlen(indxinfo->indstatcols) != 0 ||
+			strlen(indxinfo->indstatvals) != 0)
+		{
+			char	  **indstatcolsarray = NULL;
+			char	  **indstatvalsarray = NULL;
+			int			nstatcols = 0;
+			int			nstatvals = 0;
+			int			j;
+
+			if (!parsePGArray(indxinfo->indstatcols, &indstatcolsarray,
+							  &nstatcols))
+				pg_fatal("could not parse index statistic columns");
+			if (!parsePGArray(indxinfo->indstatvals, &indstatvalsarray,
+							  &nstatvals))
+				pg_fatal("could not parse index statistic values");
+			if (nstatcols != nstatvals)
+				pg_fatal("mismatched number of columns and values for index statistics");
+
+			for (j = 0; j < nstatcols; j++)
+			{
+				appendPQExpBuffer(q, "ALTER INDEX %s ",
+								  fmtQualifiedDumpable(indxinfo));
+
+				/*
+				 * Note that this is a column number, so no quotes should be
+				 * used.
+				 */
+				appendPQExpBuffer(q, "ALTER COLUMN %s ",
+								  indstatcolsarray[j]);
+				appendPQExpBuffer(q, "SET STATISTICS %s;\n",
+								  indstatvalsarray[j]);
+			}
+
+			free(indstatcolsarray);
+			free(indstatvalsarray);
+		}
+
 		/* If the index defines identity, we need to record that. */
 		if (indxinfo->indisreplident)
 		{
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 9258948b583..bff7ca4b0ed 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -3976,6 +3976,26 @@ my %tests = (
 		},
 	},
 
+	'CREATE TABLE table_with_constraint_stats' => {
+		create_order => 98,
+		create_sql => 'CREATE TABLE dump_test.table_constraint_stats (
+						   col1 int);
+						 ALTER TABLE dump_test.table_constraint_stats
+						   ADD CONSTRAINT ex_with_stats
+						   EXCLUDE USING btree ((col1 + 1) WITH =);
+						 ALTER INDEX dump_test.ex_with_stats
+						   ALTER COLUMN 1 SET STATISTICS 100;',
+		regexp => qr/^
+			\QALTER INDEX dump_test.ex_with_stats ALTER COLUMN 1 SET STATISTICS 100;\E\n
+			/xms,
+		like =>
+		  { %full_runs, %dump_test_schema_runs, section_post_data => 1, },
+		unlike => {
+			exclude_dump_test_schema => 1,
+			only_dump_measurement => 1,
+		},
+	},
+
 	'CREATE TABLE test_inheritance_parent' => {
 		create_order => 90,
 		create_sql => 'CREATE TABLE dump_test.test_inheritance_parent (
-- 
2.54.0