clean-up-reindex-state-properly.patch

diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 6b1ae1f..a979256 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -30,6 +30,7 @@
 #include "access/xlog.h"
 #include "access/xloginsert.h"
 #include "access/xlogutils.h"
+#include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_enum.h"
 #include "catalog/storage.h"
@@ -2662,6 +2663,9 @@ AbortTransaction(void)
 	 */
 	SetUserIdAndSecContext(s->prevUser, s->prevSecContext);
 
+	/* Forget about any active REINDEX. */
+	ResetReindexState();
+
 	/* If in parallel mode, clean up workers and exit parallel mode. */
 	if (IsInParallelMode())
 	{
@@ -4961,6 +4965,9 @@ AbortSubTransaction(void)
 	 */
 	SetUserIdAndSecContext(s->prevUser, s->prevSecContext);
 
+	/* Forget about any active REINDEX. */
+	ResetReindexState();
+
 	/* Exit from parallel mode, if necessary. */
 	if (IsInParallelMode())
 	{
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index bd7ec92..321d9d6 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -131,7 +131,6 @@ static void SetReindexProcessing(Oid heapOid, Oid indexOid);
 static void ResetReindexProcessing(void);
 static void SetReindexPending(List *indexes);
 static void RemoveReindexPending(Oid indexOid);
-static void ResetReindexPending(void);
 
 
 /*
@@ -3525,9 +3524,6 @@ reindex_index(Oid indexId, bool skip_constraint_checks, char persistence,
 		indexInfo->ii_ExclusionStrats = NULL;
 	}
 
-	/* ensure SetReindexProcessing state isn't leaked */
-	PG_TRY();
-	{
 		/* Suppress use of the target index while rebuilding it */
 		SetReindexProcessing(heapId, indexId);
 
@@ -3537,13 +3533,9 @@ reindex_index(Oid indexId, bool skip_constraint_checks, char persistence,
 		/* Initialize the index and rebuild */
 		/* Note: we do not need to re-establish pkey setting */
 		index_build(heapRelation, iRel, indexInfo, true, true);
-	}
-	PG_FINALLY();
-	{
-		/* Make sure flag gets cleared on error exit */
+
+		/* Re-allow use of target index */
 		ResetReindexProcessing();
-	}
-	PG_END_TRY();
 
 	/*
 	 * If the index is marked invalid/not-ready/dead (ie, it's from a failed
@@ -3715,7 +3707,6 @@ reindex_relation(Oid relid, int flags, int options)
 	 */
 	indexIds = RelationGetIndexList(rel);
 
-	PG_TRY();
 	{
 		ListCell   *indexId;
 		char		persistence;
@@ -3780,12 +3771,6 @@ reindex_relation(Oid relid, int flags, int options)
 			i++;
 		}
 	}
-	PG_FINALLY();
-	{
-		/* Make sure list gets cleared on error exit */
-		ResetReindexPending();
-	}
-	PG_END_TRY();
 
 	/*
 	 * Close rel, but continue to hold the lock.
@@ -3819,6 +3804,7 @@ reindex_relation(Oid relid, int flags, int options)
 static Oid	currentlyReindexedHeap = InvalidOid;
 static Oid	currentlyReindexedIndex = InvalidOid;
 static List *pendingReindexedIndexes = NIL;
+static int	reindexingNestLevel = 0;
 
 /*
  * ReindexIsProcessingHeap
@@ -3855,8 +3841,6 @@ ReindexIsProcessingIndex(Oid indexOid)
 /*
  * SetReindexProcessing
  *		Set flag that specified heap/index are being reindexed.
- *
- * NB: caller must use a PG_TRY block to ensure ResetReindexProcessing is done.
  */
 static void
 SetReindexProcessing(Oid heapOid, Oid indexOid)
@@ -3869,6 +3853,8 @@ SetReindexProcessing(Oid heapOid, Oid indexOid)
 	currentlyReindexedIndex = indexOid;
 	/* Index is no longer "pending" reindex. */
 	RemoveReindexPending(indexOid);
+	/* This may have been set already, but in case it isn't, do so now. */
+	reindexingNestLevel = GetCurrentTransactionNestLevel();
 }
 
 /*
@@ -3878,17 +3864,16 @@ SetReindexProcessing(Oid heapOid, Oid indexOid)
 static void
 ResetReindexProcessing(void)
 {
-	/* This may be called in leader error path */
 	currentlyReindexedHeap = InvalidOid;
 	currentlyReindexedIndex = InvalidOid;
+	/* reindexingNestLevel remains set till end of (sub)transaction */
 }
 
 /*
  * SetReindexPending
  *		Mark the given indexes as pending reindex.
  *
- * NB: caller must use a PG_TRY block to ensure ResetReindexPending is done.
- * Also, we assume that the current memory context stays valid throughout.
+ * NB: we assume that the current memory context stays valid throughout.
  */
 static void
 SetReindexPending(List *indexes)
@@ -3899,6 +3884,7 @@ SetReindexPending(List *indexes)
 	if (IsInParallelMode())
 		elog(ERROR, "cannot modify reindex state during a parallel operation");
 	pendingReindexedIndexes = list_copy(indexes);
+	reindexingNestLevel = GetCurrentTransactionNestLevel();
 }
 
 /*
@@ -3915,14 +3901,32 @@ RemoveReindexPending(Oid indexOid)
 }
 
 /*
- * ResetReindexPending
- *		Unset reindex-pending status.
+ * ResetReindexState
+ *		Clear all reindexing state during (sub)transaction abort.
  */
-static void
-ResetReindexPending(void)
+void
+ResetReindexState(void)
 {
-	/* This may be called in leader error path */
-	pendingReindexedIndexes = NIL;
+	/*
+	 * Because reindexing is not re-entrant, we don't need to cope with nested
+	 * reindexing states.  We just need to avoid messing up the outer-level
+	 * state in case a subtransaction fails within a REINDEX.  So checking the
+	 * current nest level against that of the reindex operation is sufficient.
+	 */
+	if (reindexingNestLevel >= GetCurrentTransactionNestLevel())
+	{
+		currentlyReindexedHeap = InvalidOid;
+		currentlyReindexedIndex = InvalidOid;
+
+		/*
+		 * We needn't try to release the contents of pendingReindexedIndexes;
+		 * that list should be in a transaction-lifespan context, so it will
+		 * go away automatically.
+		 */
+		pendingReindexedIndexes = NIL;
+
+		reindexingNestLevel = 0;
+	}
 }
 
 /*
@@ -3975,4 +3979,7 @@ RestoreReindexState(void *reindexstate)
 			lappend_oid(pendingReindexedIndexes,
 						sistate->pendingReindexedIndexes[c]);
 	MemoryContextSwitchTo(oldcontext);
+
+	/* Note the worker has its own transaction nesting level */
+	reindexingNestLevel = GetCurrentTransactionNestLevel();
 }
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index a2890c1..887d300 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -131,6 +131,8 @@ extern void validate_index(Oid heapId, Oid indexId, Snapshot snapshot);
 
 extern void index_set_state_flags(Oid indexId, IndexStateFlagsAction action);
 
+extern Oid	IndexGetRelation(Oid indexId, bool missing_ok);
+
 extern void reindex_index(Oid indexId, bool skip_constraint_checks,
 						  char relpersistence, int options);
 
@@ -145,8 +147,8 @@ extern bool reindex_relation(Oid relid, int flags, int options);
 
 extern bool ReindexIsProcessingHeap(Oid heapOid);
 extern bool ReindexIsProcessingIndex(Oid indexOid);
-extern Oid	IndexGetRelation(Oid indexId, bool missing_ok);
 
+extern void ResetReindexState(void);
 extern Size EstimateReindexStateSpace(void);
 extern void SerializeReindexState(Size maxsize, char *start_address);
 extern void RestoreReindexState(void *reindexstate);