6 files changed, 41 insertions, 12 deletions

diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 13dee840593..8655b56c5e2 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -862,7 +862,15 @@ pgstat_vacuum_stat(void)
 			CHECK_FOR_INTERRUPTS();
 
 			if (SearchNamedReplicationSlot(NameStr(slotentry->slotname), true) == NULL)
-				pgstat_report_replslot_drop(NameStr(slotentry->slotname));
+			{
+				PgStat_MsgReplSlot msg;
+
+				pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_REPLSLOT);
+				namestrcpy(&msg.m_slotname, NameStr(slotentry->slotname));
+				msg.m_create = false;
+				msg.m_drop = true;
+				pgstat_send(&msg, sizeof(PgStat_MsgReplSlot));
+			}
 		}
 	}
 
diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c
index e1f14aeecb5..656ec8f5555 100644
--- a/src/backend/replication/logical/logical.c
+++ b/src/backend/replication/logical/logical.c
@@ -1921,7 +1921,7 @@ UpdateDecodingStats(LogicalDecodingContext *ctx)
 	repSlotStat.total_txns = rb->totalTxns;
 	repSlotStat.total_bytes = rb->totalBytes;
 
-	pgstat_report_replslot(&repSlotStat);
+	pgstat_report_replslot(ctx->slot, &repSlotStat);
 
 	rb->spillTxns = 0;
 	rb->spillCount = 0;
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index ed4c8b3ad55..2217af70d43 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -356,7 +356,7 @@ ReplicationSlotCreate(const char *name, bool db_specific,
 	 * ReplicationSlotAllocationLock.
 	 */
 	if (SlotIsLogical(slot))
-		pgstat_report_replslot_create(NameStr(slot->data.name));
+		pgstat_create_replslot(slot);
 
 	/*
 	 * Now that the slot has been marked as in_use and active, it's safe to
@@ -400,6 +400,22 @@ SearchNamedReplicationSlot(const char *name, bool need_lock)
 }
 
 /*
+ * Return the index of the replication slot in
+ * ReplicationSlotCtl->replication_slots.
+ *
+ * This is mainly useful to have an efficient key for storing replication slot
+ * stats.
+ */
+int
+ReplicationSlotIndex(ReplicationSlot *slot)
+{
+	Assert(slot >= ReplicationSlotCtl->replication_slots &&
+		   slot < ReplicationSlotCtl->replication_slots + max_replication_slots);
+
+	return slot - ReplicationSlotCtl->replication_slots;
+}
+
+/*
  * Find a previously created slot and mark it as used by this process.
  *
  * An error is raised if nowait is true and the slot is currently in use. If
@@ -746,7 +762,7 @@ ReplicationSlotDropPtr(ReplicationSlot *slot)
 	 * doesn't seem worth doing as in practice this won't happen frequently.
 	 */
 	if (SlotIsLogical(slot))
-		pgstat_report_replslot_drop(NameStr(slot->data.name));
+		pgstat_drop_replslot(slot);
 
 	/*
 	 * We release this at the very end, so that nobody starts trying to create
diff --git a/src/backend/utils/activity/pgstat_replslot.c b/src/backend/utils/activity/pgstat_replslot.c
index cfaf8d546c5..ceefc5d59b3 100644
--- a/src/backend/utils/activity/pgstat_replslot.c
+++ b/src/backend/utils/activity/pgstat_replslot.c
@@ -69,7 +69,7 @@ pgstat_reset_replslot(const char *name)
  * Report replication slot statistics.
  */
 void
-pgstat_report_replslot(const PgStat_StatReplSlotEntry *repSlotStat)
+pgstat_report_replslot(ReplicationSlot *slot, const PgStat_StatReplSlotEntry *repSlotStat)
 {
 	PgStat_MsgReplSlot msg;
 
@@ -93,14 +93,17 @@ pgstat_report_replslot(const PgStat_StatReplSlotEntry *repSlotStat)
 
 /*
  * Report replication slot creation.
+ *
+ * NB: This gets called with ReplicationSlotAllocationLock already held, be
+ * careful about calling back into slot.c.
  */
 void
-pgstat_report_replslot_create(const char *slotname)
+pgstat_create_replslot(ReplicationSlot *slot)
 {
 	PgStat_MsgReplSlot msg;
 
 	pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_REPLSLOT);
-	namestrcpy(&msg.m_slotname, slotname);
+	namestrcpy(&msg.m_slotname, NameStr(slot->data.name));
 	msg.m_create = true;
 	msg.m_drop = false;
 	pgstat_send(&msg, sizeof(PgStat_MsgReplSlot));
@@ -110,12 +113,12 @@ pgstat_report_replslot_create(const char *slotname)
  * Report replication slot drop.
  */
 void
-pgstat_report_replslot_drop(const char *slotname)
+pgstat_drop_replslot(ReplicationSlot *slot)
 {
 	PgStat_MsgReplSlot msg;
 
 	pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_REPLSLOT);
-	namestrcpy(&msg.m_slotname, slotname);
+	namestrcpy(&msg.m_slotname, NameStr(slot->data.name));
 	msg.m_create = false;
 	msg.m_drop = true;
 	pgstat_send(&msg, sizeof(PgStat_MsgReplSlot));
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 7981a816565..0c618e77103 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -1137,9 +1137,10 @@ extern PgStat_TableStatus *find_tabstat_entry(Oid rel_id);
  */
 
 extern void pgstat_reset_replslot(const char *name);
-extern void pgstat_report_replslot(const PgStat_StatReplSlotEntry *repSlotStat);
-extern void pgstat_report_replslot_create(const char *slotname);
-extern void pgstat_report_replslot_drop(const char *slotname);
+struct ReplicationSlot;
+extern void pgstat_report_replslot(struct ReplicationSlot *slot, const PgStat_StatReplSlotEntry *repSlotStat);
+extern void pgstat_create_replslot(struct ReplicationSlot *slot);
+extern void pgstat_drop_replslot(struct ReplicationSlot *slot);
 
 
 /*
diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h
index 24b30210c3e..1ee63c4cf44 100644
--- a/src/include/replication/slot.h
+++ b/src/include/replication/slot.h
@@ -216,6 +216,7 @@ extern bool ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive);
 extern void ReplicationSlotsDropDBSlots(Oid dboid);
 extern bool InvalidateObsoleteReplicationSlots(XLogSegNo oldestSegno);
 extern ReplicationSlot *SearchNamedReplicationSlot(const char *name, bool need_lock);
+extern int ReplicationSlotIndex(ReplicationSlot *slot);
 extern void ReplicationSlotNameForTablesync(Oid suboid, Oid relid, char *syncslotname, int szslot);
 extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname, bool missing_ok);