6 files changed, 41 insertions, 1 deletions
diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c
index 5415604993a..ea7bfa0578b 100644
--- a/src/backend/access/transam/twophase.c
+++ b/src/backend/access/transam/twophase.c
@@ -420,6 +420,7 @@ MarkAsPreparing(TransactionId xid, const char *gid,
 	proc->backendId = InvalidBackendId;
 	proc->databaseId = databaseid;
 	proc->roleId = owner;
+	proc->isBackgroundWorker = false;
 	proc->lwWaiting = false;
 	proc->lwWaitMode = 0;
 	proc->waitLock = NULL;
diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c
index 4adb286d5b5..651c561dfd5 100644
--- a/src/backend/storage/ipc/procarray.c
+++ b/src/backend/storage/ipc/procarray.c
@@ -2752,6 +2752,38 @@ CountDBBackends(Oid databaseid)
 }
 
 /*
+ * CountDBConnections --- counts database backends ignoring any background
+ *		worker processes
+ */
+int
+CountDBConnections(Oid databaseid)
+{
+	ProcArrayStruct *arrayP = procArray;
+	int			count = 0;
+	int			index;
+
+	LWLockAcquire(ProcArrayLock, LW_SHARED);
+
+	for (index = 0; index < arrayP->numProcs; index++)
+	{
+		int			pgprocno = arrayP->pgprocnos[index];
+		volatile PGPROC *proc = &allProcs[pgprocno];
+
+		if (proc->pid == 0)
+			continue;			/* do not count prepared xacts */
+		if (proc->isBackgroundWorker)
+			continue;			/* do not count background workers */
+		if (!OidIsValid(databaseid) ||
+			proc->databaseId == databaseid)
+			count++;
+	}
+
+	LWLockRelease(ProcArrayLock);
+
+	return count;
+}
+
+/*
  * CancelDBBackends --- cancel backends that are using specified database
  */
 void
@@ -2810,6 +2842,8 @@ CountUserBackends(Oid roleid)
 
 		if (proc->pid == 0)
 			continue;			/* do not count prepared xacts */
+		if (proc->isBackgroundWorker)
+			continue;			/* do not count background workers */
 		if (proc->roleId == roleid)
 			count++;
 	}
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 9a758bd9160..cb6e1e3e5bc 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -372,6 +372,7 @@ InitProcess(void)
 	MyProc->backendId = InvalidBackendId;
 	MyProc->databaseId = InvalidOid;
 	MyProc->roleId = InvalidOid;
+	MyProc->isBackgroundWorker = IsBackgroundWorker;
 	MyPgXact->delayChkpt = false;
 	MyPgXact->vacuumFlags = 0;
 	/* NB -- autovac launcher intentionally does not set IS_AUTOVACUUM */
@@ -544,6 +545,7 @@ InitAuxiliaryProcess(void)
 	MyProc->backendId = InvalidBackendId;
 	MyProc->databaseId = InvalidOid;
 	MyProc->roleId = InvalidOid;
+	MyProc->isBackgroundWorker = IsBackgroundWorker;
 	MyPgXact->delayChkpt = false;
 	MyPgXact->vacuumFlags = 0;
 	MyProc->lwWaiting = false;
diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c
index 824d5abf11f..cde4a798b62 100644
--- a/src/backend/utils/init/postinit.c
+++ b/src/backend/utils/init/postinit.c
@@ -350,7 +350,7 @@ CheckMyDatabase(const char *name, bool am_superuser)
 		 */
 		if (dbform->datconnlimit >= 0 &&
 			!am_superuser &&
-			CountDBBackends(MyDatabaseId) > dbform->datconnlimit)
+			CountDBConnections(MyDatabaseId) > dbform->datconnlimit)
 			ereport(FATAL,
 					(errcode(ERRCODE_TOO_MANY_CONNECTIONS),
 					 errmsg("too many connections for database \"%s\"",
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 775c66a1971..c44d82b90c0 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -102,6 +102,8 @@ struct PGPROC
 	Oid			databaseId;		/* OID of database this backend is using */
 	Oid			roleId;			/* OID of role using this backend */
 
+	bool		isBackgroundWorker; /* true if background worker. */
+
 	/*
 	 * While in hot standby mode, shows that a conflict signal has been sent
 	 * for the current transaction. Set/cleared while holding ProcArrayLock,
diff --git a/src/include/storage/procarray.h b/src/include/storage/procarray.h
index dd37c0cb070..ecc3c4a4f63 100644
--- a/src/include/storage/procarray.h
+++ b/src/include/storage/procarray.h
@@ -73,6 +73,7 @@ extern pid_t CancelVirtualTransaction(VirtualTransactionId vxid, ProcSignalReaso
 
 extern bool MinimumActiveBackends(int min);
 extern int	CountDBBackends(Oid databaseid);
+extern int	CountDBConnections(Oid databaseid);
 extern void CancelDBBackends(Oid databaseid, ProcSignalReason sigmode, bool conflictPending);
 extern int	CountUserBackends(Oid roleid);
 extern bool CountOtherDBBackends(Oid databaseId,