Replace XLOG_INCLUDE_XID flag with a more localized flag.

Commit 0bead9af484c introduced XLOG_INCLUDE_XID flag to indicate that the
WAL record contains subXID-to-topXID association. It uses that flag later
to mark in CurrentTransactionState that top-xid is logged so that we
should not try to log it again with the next WAL record in the current
subtransaction. However, we can use a localized variable to pass that
information.

In passing, change the related function and variable names to make them
consistent with what the code is actually doing.

Author: Dilip Kumar
Reviewed-by: Alvaro Herrera, Amit Kapila
Discussion: https://postgr.es/m/E1mSoYz-0007Fh-D9@gemulon.postgresql.org

1 files changed, 53 insertions, 50 deletions

diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index ca6f6d57d36..8e35c432f5c 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -205,7 +205,7 @@ typedef struct TransactionStateData
 	bool		didLogXid;		/* has xid been included in WAL record? */
 	int			parallelModeLevel;	/* Enter/ExitParallelMode counter */
 	bool		chain;			/* start a new block after this one */
-	bool		assigned;		/* assigned to top-level XID */
+	bool		topXidLogged;	/* for a subxact: is top-level XID logged? */
 	struct TransactionStateData *parent;	/* back link to parent */
 } TransactionStateData;
 
@@ -238,7 +238,7 @@ typedef struct SerializedTransactionState
 static TransactionStateData TopTransactionStateData = {
 	.state = TRANS_DEFAULT,
 	.blockState = TBLOCK_DEFAULT,
-	.assigned = false,
+	.topXidLogged = false,
 };
 
 /*
@@ -529,6 +529,56 @@ MarkCurrentTransactionIdLoggedIfAny(void)
 		CurrentTransactionState->didLogXid = true;
 }
 
+/*
+ * IsSubxactTopXidLogPending
+ *
+ * This is used to decide whether we need to WAL log the top-level XID for
+ * operation in a subtransaction.  We require that for logical decoding, see
+ * LogicalDecodingProcessRecord.
+ *
+ * This returns true if wal_level >= logical and we are inside a valid
+ * subtransaction, for which the assignment was not yet written to any WAL
+ * record.
+ */
+bool
+IsSubxactTopXidLogPending(void)
+{
+	/* check whether it is already logged */
+	if (CurrentTransactionState->topXidLogged)
+		return false;
+
+	/* wal_level has to be logical */
+	if (!XLogLogicalInfoActive())
+		return false;
+
+	/* we need to be in a transaction state */
+	if (!IsTransactionState())
+		return false;
+
+	/* it has to be a subtransaction */
+	if (!IsSubTransaction())
+		return false;
+
+	/* the subtransaction has to have a XID assigned */
+	if (!TransactionIdIsValid(GetCurrentTransactionIdIfAny()))
+		return false;
+
+	return true;
+}
+
+/*
+ * MarkSubxactTopXidLogged
+ *
+ * Remember that the top transaction id for the current subtransaction is WAL
+ * logged now.
+ */
+void
+MarkSubxactTopXidLogged(void)
+{
+	Assert(IsSubxactTopXidLogPending());
+
+	CurrentTransactionState->topXidLogged = true;
+}
 
 /*
  *	GetStableLatestTransactionId
@@ -5174,7 +5224,7 @@ PushTransaction(void)
 	GetUserIdAndSecContext(&s->prevUser, &s->prevSecContext);
 	s->prevXactReadOnly = XactReadOnly;
 	s->parallelModeLevel = 0;
-	s->assigned = false;
+	s->topXidLogged = false;
 
 	CurrentTransactionState = s;
 
@@ -6106,50 +6156,3 @@ xact_redo(XLogReaderState *record)
 	else
 		elog(PANIC, "xact_redo: unknown op code %u", info);
 }
-
-/*
- * IsSubTransactionAssignmentPending
- *
- * This is used to decide whether we need to WAL log the top-level XID for
- * operation in a subtransaction.  We require that for logical decoding, see
- * LogicalDecodingProcessRecord.
- *
- * This returns true if wal_level >= logical and we are inside a valid
- * subtransaction, for which the assignment was not yet written to any WAL
- * record.
- */
-bool
-IsSubTransactionAssignmentPending(void)
-{
-	/* wal_level has to be logical */
-	if (!XLogLogicalInfoActive())
-		return false;
-
-	/* we need to be in a transaction state */
-	if (!IsTransactionState())
-		return false;
-
-	/* it has to be a subtransaction */
-	if (!IsSubTransaction())
-		return false;
-
-	/* the subtransaction has to have a XID assigned */
-	if (!TransactionIdIsValid(GetCurrentTransactionIdIfAny()))
-		return false;
-
-	/* and it should not be already 'assigned' */
-	return !CurrentTransactionState->assigned;
-}
-
-/*
- * MarkSubTransactionAssigned
- *
- * Mark the subtransaction assignment as completed.
- */
-void
-MarkSubTransactionAssigned(void)
-{
-	Assert(IsSubTransactionAssignmentPending());
-
-	CurrentTransactionState->assigned = true;
-}