Refactor cluster_rel() to handle more options

This extends cluster_rel() in such a way that more options can be added
in the future, which will reduce the amount of chunk code for an
upcoming SKIP_LOCKED aimed for VACUUM.  As VACUUM FULL is a different
flavor of CLUSTER, we want to make that extensible to ease integration.

This only reworks the API and its callers, without providing anything
user-facing.  Two options are present now: verbose mode and relation
recheck when doing the cluster command work across multiple
transactions.  This could be used as well as a base to extend the
grammar of CLUSTER later on.

Author: Michael Paquier
Reviewed-by: Nathan Bossart
Discussion: https://postgr.es/m/20180723031058.GE2854@paquier.xyz

Author: michaelpq

src/backend/commands/cluster.c

@@ -186,7 +186,7 @@ cluster(ClusterStmt *stmt, bool isTopLevel)
 		heap_close(rel, NoLock);
 
 		/* Do the job. */
-		cluster_rel(tableOid, indexOid, false, stmt->verbose);
+		cluster_rel(tableOid, indexOid, stmt->options);
 	}
 	else
 	{
@@ -234,7 +234,8 @@ cluster(ClusterStmt *stmt, bool isTopLevel)
 			/* functions in indexes may want a snapshot set */
 			PushActiveSnapshot(GetTransactionSnapshot());
 			/* Do the job. */
-			cluster_rel(rvtc->tableOid, rvtc->indexOid, true, stmt->verbose);
+			cluster_rel(rvtc->tableOid, rvtc->indexOid,
+						stmt->options | CLUOPT_RECHECK);
 			PopActiveSnapshot();
 			CommitTransactionCommand();
 		}
@@ -265,9 +266,11 @@ cluster(ClusterStmt *stmt, bool isTopLevel)
  * and error messages should refer to the operation as VACUUM not CLUSTER.
  */
 void
-cluster_rel(Oid tableOid, Oid indexOid, bool recheck, bool verbose)
+cluster_rel(Oid tableOid, Oid indexOid, int options)
 {
 	Relation	OldHeap;
+	bool		verbose = ((options & CLUOPT_VERBOSE) != 0);
+	bool		recheck = ((options & CLUOPT_RECHECK) != 0);
 
 	/* Check for user-requested abort. */
 	CHECK_FOR_INTERRUPTS();

src/backend/commands/vacuum.c

@@ -1551,13 +1551,17 @@ vacuum_rel(Oid relid, RangeVar *relation, int options, VacuumParams *params)
 	 */
 	if (options & VACOPT_FULL)
 	{
+		int			options = 0;
+
 		/* close relation before vacuuming, but hold lock until commit */
 		relation_close(onerel, NoLock);
 		onerel = NULL;
 
+		if ((options & VACOPT_VERBOSE) != 0)
+			options |= CLUOPT_VERBOSE;
+
 		/* VACUUM FULL is now a variant of CLUSTER; see cluster.c */
-		cluster_rel(relid, InvalidOid, false,
-					(options & VACOPT_VERBOSE) != 0);
+		cluster_rel(relid, InvalidOid, options);
 	}
 	else
 		lazy_vacuum_rel(onerel, options, params, vac_strategy);

src/backend/nodes/copyfuncs.c

@@ -3284,7 +3284,7 @@ _copyClusterStmt(const ClusterStmt *from)
 
 	COPY_NODE_FIELD(relation);
 	COPY_STRING_FIELD(indexname);
-	COPY_SCALAR_FIELD(verbose);
+	COPY_SCALAR_FIELD(options);
 
 	return newnode;
 }

src/backend/nodes/equalfuncs.c

@@ -1206,7 +1206,7 @@ _equalClusterStmt(const ClusterStmt *a, const ClusterStmt *b)
 {
 	COMPARE_NODE_FIELD(relation);
 	COMPARE_STRING_FIELD(indexname);
-	COMPARE_SCALAR_FIELD(verbose);
+	COMPARE_SCALAR_FIELD(options);
 
 	return true;
 }

src/backend/parser/gram.y

@@ -10478,15 +10478,19 @@ ClusterStmt:
 					ClusterStmt *n = makeNode(ClusterStmt);
 					n->relation = $3;
 					n->indexname = $4;
-					n->verbose = $2;
+					n->options = 0;
+					if ($2)
+						n->options |= CLUOPT_VERBOSE;
 					$$ = (Node*)n;
 				}
 			| CLUSTER opt_verbose
 				{
 					ClusterStmt *n = makeNode(ClusterStmt);
 					n->relation = NULL;
 					n->indexname = NULL;
-					n->verbose = $2;
+					n->options = 0;
+					if ($2)
+						n->options |= CLUOPT_VERBOSE;
 					$$ = (Node*)n;
 				}
 			/* kept for pre-8.3 compatibility */
@@ -10495,7 +10499,9 @@ ClusterStmt:
 					ClusterStmt *n = makeNode(ClusterStmt);
 					n->relation = $5;
 					n->indexname = $3;
-					n->verbose = $2;
+					n->options = 0;
+					if ($2)
+						n->options |= CLUOPT_VERBOSE;
 					$$ = (Node*)n;
 				}
 		;

src/include/commands/cluster.h

@@ -19,8 +19,7 @@
 
 
 extern void cluster(ClusterStmt *stmt, bool isTopLevel);
-extern void cluster_rel(Oid tableOid, Oid indexOid, bool recheck,
-			bool verbose);
+extern void cluster_rel(Oid tableOid, Oid indexOid, int options);
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 						   bool recheck, LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);

src/include/nodes/parsenodes.h

@@ -3112,12 +3112,18 @@ typedef struct AlterSystemStmt
  *		Cluster Statement (support pbrown's cluster index implementation)
  * ----------------------
  */
+typedef enum ClusterOption
+{
+	CLUOPT_RECHECK,				/* recheck relation state */
+	CLUOPT_VERBOSE				/* print progress info */
+} ClusterOption;
+
 typedef struct ClusterStmt
 {
 	NodeTag		type;
 	RangeVar   *relation;		/* relation being indexed, or NULL if all */
 	char	   *indexname;		/* original index defined */
-	bool		verbose;		/* print progress info */
+	int			options;		/* OR of ClusterOption flags */
 } ClusterStmt;
 
 /* ----------------------

src/tools/pgindent/typedefs.list

@@ -330,6 +330,7 @@ ClosePortalStmt
 ClosePtrType
 Clump
 ClusterInfo
+ClusterOption
 ClusterStmt
 CmdType
 CoalesceExpr