Refactor GetOldestXmin() to use flags

Replace ignoreVacuum parameter with more flexible flags.

Author: Eiji Seki
Review: Haribabu Kommi

contrib/pg_visibility/pg_visibility.c

@@ -557,7 +557,7 @@ collect_corrupt_items(Oid relid, bool all_visible, bool all_frozen)
 	if (all_visible)
 	{
 		/* Don't pass rel; that will fail in recovery. */
-		OldestXmin = GetOldestXmin(NULL, true);
+		OldestXmin = GetOldestXmin(NULL, PROCARRAY_FLAGS_VACUUM);
 	}
 
 	rel = relation_open(relid, AccessShareLock);
@@ -674,7 +674,7 @@ collect_corrupt_items(Oid relid, bool all_visible, bool all_frozen)
 				 * a buffer lock. And this shouldn't happen often, so it's
 				 * worth being careful so as to avoid false positives.
 				 */
-				RecomputedOldestXmin = GetOldestXmin(NULL, true);
+				RecomputedOldestXmin = GetOldestXmin(NULL, PROCARRAY_FLAGS_VACUUM);
 
 				if (!TransactionIdPrecedes(OldestXmin, RecomputedOldestXmin))
 					record_corrupt_item(items, &tuple.t_self);

contrib/pgstattuple/pgstatapprox.c

@@ -70,7 +70,7 @@ statapprox_heap(Relation rel, output_type *stat)
 	TransactionId OldestXmin;
 	uint64		misc_count = 0;
 
-	OldestXmin = GetOldestXmin(rel, true);
+	OldestXmin = GetOldestXmin(rel, PROCARRAY_FLAGS_VACUUM);
 	bstrategy = GetAccessStrategy(BAS_BULKREAD);
 
 	nblocks = RelationGetNumberOfBlocks(rel);

src/backend/access/transam/xlog.c

@@ -8895,7 +8895,7 @@ CreateCheckPoint(int flags)
 	 * StartupSUBTRANS hasn't been called yet.
 	 */
 	if (!RecoveryInProgress())
-		TruncateSUBTRANS(GetOldestXmin(NULL, false));
+		TruncateSUBTRANS(GetOldestXmin(NULL, PROCARRAY_FLAGS_DEFAULT));
 
 	/* Real work is done, but log and update stats before releasing lock. */
 	LogCheckpointEnd(false);
@@ -9258,7 +9258,7 @@ CreateRestartPoint(int flags)
 	 * this because StartupSUBTRANS hasn't been called yet.
 	 */
 	if (EnableHotStandby)
-		TruncateSUBTRANS(GetOldestXmin(NULL, false));
+		TruncateSUBTRANS(GetOldestXmin(NULL, PROCARRAY_FLAGS_DEFAULT));
 
 	/* Real work is done, but log and update before releasing lock. */
 	LogCheckpointEnd(true);

src/backend/catalog/index.c

@@ -2270,7 +2270,7 @@ IndexBuildHeapRangeScan(Relation heapRelation,
 	{
 		snapshot = SnapshotAny;
 		/* okay to ignore lazy VACUUMs here */
-		OldestXmin = GetOldestXmin(heapRelation, true);
+		OldestXmin = GetOldestXmin(heapRelation, PROCARRAY_FLAGS_VACUUM);
 	}
 
 	scan = heap_beginscan_strat(heapRelation,	/* relation */

src/backend/commands/analyze.c

@@ -1000,7 +1000,7 @@ acquire_sample_rows(Relation onerel, int elevel,
 	totalblocks = RelationGetNumberOfBlocks(onerel);
 
 	/* Need a cutoff xmin for HeapTupleSatisfiesVacuum */
-	OldestXmin = GetOldestXmin(onerel, true);
+	OldestXmin = GetOldestXmin(onerel, PROCARRAY_FLAGS_VACUUM);
 
 	/* Prepare for sampling block numbers */
 	BlockSampler_Init(&bs, totalblocks, targrows, random());

src/backend/commands/vacuum.c

@@ -527,7 +527,7 @@ vacuum_set_xid_limits(Relation rel,
 	 * always an independent transaction.
 	 */
 	*oldestXmin =
-		TransactionIdLimitedForOldSnapshots(GetOldestXmin(rel, true), rel);
+		TransactionIdLimitedForOldSnapshots(GetOldestXmin(rel, PROCARRAY_FLAGS_VACUUM), rel);
 
 	Assert(TransactionIdIsNormal(*oldestXmin));
 
@@ -939,7 +939,7 @@ vac_update_datfrozenxid(void)
 	 * committed pg_class entries for new tables; see AddNewRelationTuple().
 	 * So we cannot produce a wrong minimum by starting with this.
 	 */
-	newFrozenXid = GetOldestXmin(NULL, true);
+	newFrozenXid = GetOldestXmin(NULL, PROCARRAY_FLAGS_VACUUM);
 
 	/*
 	 * Similarly, initialize the MultiXact "min" with the value that would be

src/backend/replication/walreceiver.c

@@ -1221,7 +1221,7 @@ XLogWalRcvSendHSFeedback(bool immed)
 	 * everything else has been checked.
 	 */
 	if (hot_standby_feedback)
-		xmin = GetOldestXmin(NULL, false);
+		xmin = GetOldestXmin(NULL, PROCARRAY_FLAGS_DEFAULT);
 	else
 		xmin = InvalidTransactionId;
 

src/backend/storage/ipc/procarray.c

@@ -1260,8 +1260,9 @@ TransactionIdIsActive(TransactionId xid)
  * If rel is NULL or a shared relation, all backends are considered, otherwise
  * only backends running in this database are considered.
  *
- * If ignoreVacuum is TRUE then backends with the PROC_IN_VACUUM flag set are
- * ignored.
+ * The flags are used to ignore the backends in calculation when any of the
+ * corresponding flags is set. Typically, if you want to ignore ones with
+ * PROC_IN_VACUUM flag, you can use PROCARRAY_FLAGS_VACUUM.
  *
  * This is used by VACUUM to decide which deleted tuples must be preserved in
  * the passed in table. For shared relations backends in all databases must be
@@ -1302,7 +1303,7 @@ TransactionIdIsActive(TransactionId xid)
  * GetOldestXmin() move backwards, with no consequences for data integrity.
  */
 TransactionId
-GetOldestXmin(Relation rel, bool ignoreVacuum)
+GetOldestXmin(Relation rel, int flags)
 {
 	ProcArrayStruct *arrayP = procArray;
 	TransactionId result;
@@ -1340,14 +1341,7 @@ GetOldestXmin(Relation rel, bool ignoreVacuum)
 		volatile PGPROC *proc = &allProcs[pgprocno];
 		volatile PGXACT *pgxact = &allPgXact[pgprocno];
 
-		/*
-		 * Backend is doing logical decoding which manages xmin separately,
-		 * check below.
-		 */
-		if (pgxact->vacuumFlags & PROC_IN_LOGICAL_DECODING)
-			continue;
-
-		if (ignoreVacuum && (pgxact->vacuumFlags & PROC_IN_VACUUM))
+		if (pgxact->vacuumFlags & flags)
 			continue;
 
 		if (allDbs ||

src/include/storage/proc.h

@@ -39,7 +39,12 @@ struct XidCache
 	TransactionId xids[PGPROC_MAX_CACHED_SUBXIDS];
 };
 
-/* Flags for PGXACT->vacuumFlags */
+/*
+ * Flags for PGXACT->vacuumFlags
+ *
+ * Note: If you modify these flags, you need to modify PROCARRAY_XXX flags
+ * in src/include/storage/procarray.h.
+ */
 #define		PROC_IS_AUTOVACUUM	0x01	/* is it an autovac worker? */
 #define		PROC_IN_VACUUM		0x02	/* currently running lazy vacuum */
 #define		PROC_IN_ANALYZE		0x04	/* currently running analyze */

src/include/storage/procarray.h

@@ -20,6 +20,28 @@
 #include "utils/snapshot.h"
 
 
+/*
+ * These are to implement PROCARRAY_FLAGS_XXX
+ *
+ * Note: These flags are cloned from PROC_XXX flags in src/include/storage/proc.h
+ * to avoid forcing to include proc.h when including procarray.h. So if you modify
+ * PROC_XXX flags, you need to modify these flags.
+ */
+#define		PROCARRAY_VACUUM_FLAG			0x02	/* currently running lazy vacuum */
+#define		PROCARRAY_ANALYZE_FLAG			0x04	/* currently running analyze */
+#define		PROCARRAY_LOGICAL_DECODING_FLAG	0x10	/* currently doing logical
+													 * decoding outside xact */
+
+/* Use the following flags as an input "flags" to GetOldestXmin function */
+/* Consider all backends except for logical decoding ones which manage xmin separately */
+#define		PROCARRAY_FLAGS_DEFAULT			PROCARRAY_LOGICAL_DECODING_FLAG
+/* Ignore vacuum backends */
+#define		PROCARRAY_FLAGS_VACUUM			PROCARRAY_FLAGS_DEFAULT | PROCARRAY_VACUUM_FLAG
+/* Ignore analyze backends */
+#define		PROCARRAY_FLAGS_ANALYZE			PROCARRAY_FLAGS_DEFAULT | PROCARRAY_ANALYZE_FLAG
+/* Ignore both vacuum and analyze backends */
+#define		PROCARRAY_FLAGS_VACUUM_ANALYZE	PROCARRAY_FLAGS_DEFAULT | PROCARRAY_VACUUM_FLAG | PROCARRAY_ANALYZE_FLAG
+
 extern Size ProcArrayShmemSize(void);
 extern void CreateSharedProcArray(void);
 extern void ProcArrayAdd(PGPROC *proc);
@@ -53,7 +75,7 @@ extern RunningTransactions GetRunningTransactionData(void);
 
 extern bool TransactionIdIsInProgress(TransactionId xid);
 extern bool TransactionIdIsActive(TransactionId xid);
-extern TransactionId GetOldestXmin(Relation rel, bool ignoreVacuum);
+extern TransactionId GetOldestXmin(Relation rel, int flags);
 extern TransactionId GetOldestActiveTransactionId(void);
 extern TransactionId GetOldestSafeDecodingTransactionId(void);