From 13503eb5905b51d22d86a3c2065c241a61cedd44 Mon Sep 17 00:00:00 2001
From: Noah Misch
Date: Mon, 30 Oct 2023 14:46:05 -0700
Subject: Diagnose !indisvalid in more SQL functions.

pgstatindex failed with ERRCODE_DATA_CORRUPTED, of the "can't-happen"
class XX.  The other functions succeeded on an empty index; they might
have malfunctioned if the failed index build left torn I/O or other
complex state.  Report an ERROR in statistics functions pgstatindex,
pgstatginindex, pgstathashindex, and pgstattuple.  Report DEBUG1 and
skip all index I/O in maintenance functions brin_desummarize_range,
brin_summarize_new_values, brin_summarize_range, and
gin_clean_pending_list.  Back-patch to v11 (all supported versions).

Discussion: https://postgr.es/m/20231001195309.a3@google.com
---
 contrib/pgstattuple/pgstatindex.c | 26 ++++++++++++++++++++++++++
 contrib/pgstattuple/pgstattuple.c |  7 +++++++
 2 files changed, 33 insertions(+)

(limited to 'contrib')

diff --git a/contrib/pgstattuple/pgstatindex.c b/contrib/pgstattuple/pgstatindex.c
index d69ac1c93df..8e5a4d6a663 100644
--- a/contrib/pgstattuple/pgstatindex.c
+++ b/contrib/pgstattuple/pgstatindex.c
@@ -237,6 +237,18 @@ pgstatindex_impl(Relation rel, FunctionCallInfo fcinfo)
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 errmsg("cannot access temporary tables of other sessions")));
 
+	/*
+	 * A !indisready index could lead to ERRCODE_DATA_CORRUPTED later, so exit
+	 * early.  We're capable of assessing an indisready&&!indisvalid index,
+	 * but the results could be confusing.  For example, the index's size
+	 * could be too low for a valid index of the table.
+	 */
+	if (!rel->rd_index->indisvalid)
+		ereport(ERROR,
+				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+				 errmsg("index \"%s\" is not valid",
+						RelationGetRelationName(rel))));
+
 	/*
 	 * Read metapage
 	 */
@@ -523,6 +535,13 @@ pgstatginindex_internal(Oid relid, FunctionCallInfo fcinfo)
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 errmsg("cannot access temporary indexes of other sessions")));
 
+	/* see pgstatindex_impl */
+	if (!rel->rd_index->indisvalid)
+		ereport(ERROR,
+				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+				 errmsg("index \"%s\" is not valid",
+						RelationGetRelationName(rel))));
+
 	/*
 	 * Read metapage
 	 */
@@ -600,6 +619,13 @@ pgstathashindex(PG_FUNCTION_ARGS)
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 errmsg("cannot access temporary indexes of other sessions")));
 
+	/* see pgstatindex_impl */
+	if (!rel->rd_index->indisvalid)
+		ereport(ERROR,
+				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+				 errmsg("index \"%s\" is not valid",
+						RelationGetRelationName(rel))));
+
 	/* Get the information we need from the metapage. */
 	memset(&stats, 0, sizeof(stats));
 	metabuf = _hash_getbuf(rel, HASH_METAPAGE, HASH_READ, LH_META_PAGE);
diff --git a/contrib/pgstattuple/pgstattuple.c b/contrib/pgstattuple/pgstattuple.c
index 93b7834b774..3bd8b96197f 100644
--- a/contrib/pgstattuple/pgstattuple.c
+++ b/contrib/pgstattuple/pgstattuple.c
@@ -259,6 +259,13 @@ pgstat_relation(Relation rel, FunctionCallInfo fcinfo)
 	}
 	else if (rel->rd_rel->relkind == RELKIND_INDEX)
 	{
+		/* see pgstatindex_impl */
+		if (!rel->rd_index->indisvalid)
+			ereport(ERROR,
+					(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					 errmsg("index \"%s\" is not valid",
+							RelationGetRelationName(rel))));
+
 		switch (rel->rd_rel->relam)
 		{
 			case BTREE_AM_OID:
-- 
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