Some tests with changing hash key

src/backend/distributed/shared_library_init.c

@@ -27,6 +27,7 @@
 #include "catalog/objectaccess.h"
 #include "catalog/pg_extension.h"
 #include "citus_version.h"
+#include "commands/dbcommands.h"
 #include "commands/explain.h"
 #include "commands/extension.h"
 #include "common/string.h"
@@ -767,7 +768,9 @@ IsSequenceOverflowError(ErrorData *edata)
 void
 StartupCitusBackend(void)
 {
-	InitializeMaintenanceDaemonBackend();
+	Oid superUser = CitusExtensionOwner();
+
+	InitializeMaintenanceDaemonBackend(get_database_name(MyDatabaseId), superUser);
 
 	/*
 	 * For query backends this will be a no-op, because InitializeBackendData

src/backend/distributed/utils/maintenanced.c

@@ -30,6 +30,7 @@
 #include "catalog/pg_authid.h"
 #include "catalog/pg_namespace.h"
 #include "commands/async.h"
+#include "commands/dbcommands.h"
 #include "commands/extension.h"
 #include "libpq/pqsignal.h"
 #include "catalog/namespace.h"
@@ -83,9 +84,10 @@ typedef struct MaintenanceDaemonControlData
 typedef struct MaintenanceDaemonDBData
 {
 	/* hash key: database to run on */
-	Oid databaseOid;
+	char databaseName[NAMEDATALEN];
 
 	/* information: which user to use */
+	NameData dbname;
 	Oid userOid;
 	pid_t workerPid;
 	bool daemonStarted;
@@ -145,32 +147,32 @@ InitializeMaintenanceDaemon(void)
  * maintenance worker if necessary.
  */
 void
-InitializeMaintenanceDaemonBackend(void)
+InitializeMaintenanceDaemonBackend(const char* databaseName, Oid userOid)
 {
-	Oid extensionOwner = CitusExtensionOwner();
 	bool found;
 
 	LWLockAcquire(&MaintenanceDaemonControl->lock, LW_EXCLUSIVE);
 
 	MaintenanceDaemonDBData *dbData = (MaintenanceDaemonDBData *) hash_search(
 		MaintenanceDaemonDBHash,
-		&MyDatabaseId,
+		databaseName,
-		HASH_ENTER_NULL,
+		HASH_ENTER,
 		&found);
 
 	if (dbData == NULL)
 	{
 		WarnMaintenanceDaemonNotStarted();
 		LWLockRelease(&MaintenanceDaemonControl->lock);
-
+		elog(LOG, "dbData is NULL");
 		return;
 	}
 
 	if (!found)
 	{
 		/* ensure the values in MaintenanceDaemonDBData are zero */
-		memset(((char *) dbData) + sizeof(Oid), 0,
+		memset(((char *) dbData) + sizeof(char)*NAMEDATALEN, 0,
-			   sizeof(MaintenanceDaemonDBData) - sizeof(Oid));
+			   sizeof(MaintenanceDaemonDBData) - sizeof(char)*NAMEDATALEN);
+
 	}
 
 	if (IsMaintenanceDaemon)
@@ -194,8 +196,8 @@ InitializeMaintenanceDaemonBackend(void)
 		memset(&worker, 0, sizeof(worker));
 
 		SafeSnprintf(worker.bgw_name, sizeof(worker.bgw_name),
-					 "Citus Maintenance Daemon: %u/%u",
+					 "Citus Maintenance Daemon: %s/%u",
-					 MyDatabaseId, extensionOwner);
+					 databaseName, userOid);
 
 		/* request ability to connect to target database */
 		worker.bgw_flags = BGWORKER_SHMEM_ACCESS | BGWORKER_BACKEND_DATABASE_CONNECTION;
@@ -213,8 +215,11 @@ InitializeMaintenanceDaemonBackend(void)
 		strcpy_s(worker.bgw_function_name, sizeof(worker.bgw_library_name),
 				 "CitusMaintenanceDaemonMain");
 
-		worker.bgw_main_arg = ObjectIdGetDatum(MyDatabaseId);
+		namestrcpy(&(dbData->dbname), databaseName);
-		memcpy_s(worker.bgw_extra, sizeof(worker.bgw_extra), &extensionOwner,
+		worker.bgw_main_arg = NameGetDatum(&(dbData->dbname));
+		elog(LOG, "worker.bgw_main_arg databaseName = %s", databaseName);
+
+		memcpy_s(worker.bgw_extra, sizeof(worker.bgw_extra), &userOid,
 				 sizeof(Oid));
 		worker.bgw_notify_pid = MyProcPid;
 
@@ -227,8 +232,10 @@ InitializeMaintenanceDaemonBackend(void)
 			return;
 		}
 
+	        elog(LOG, "RegisterDynamicBackgroundWorker");
+
 		dbData->daemonStarted = true;
-		dbData->userOid = extensionOwner;
+		dbData->userOid = userOid;
 		dbData->workerPid = 0;
 		dbData->triggerNodeMetadataSync = false;
 		LWLockRelease(&MaintenanceDaemonControl->lock);
@@ -246,9 +253,9 @@ InitializeMaintenanceDaemonBackend(void)
 		 * If owner of extension changed, wake up daemon. It'll notice and
 		 * restart.
 		 */
-		if (dbData->userOid != extensionOwner)
+		if (dbData->userOid != userOid)
 		{
-			dbData->userOid = extensionOwner;
+			dbData->userOid = userOid;
 			if (dbData->latch)
 			{
 				SetLatch(dbData->latch);
@@ -278,7 +285,9 @@ WarnMaintenanceDaemonNotStarted(void)
 void
 CitusMaintenanceDaemonMain(Datum main_arg)
 {
-	Oid databaseOid = DatumGetObjectId(main_arg);
+	char* databaseName = NameStr(*DatumGetName(main_arg));
+
+	elog(LOG, "databaseName = %s", databaseName);
 	TimestampTz nextStatsCollectionTime USED_WITH_LIBCURL_ONLY =
 		TimestampTzPlusMilliseconds(GetCurrentTimestamp(), 60 * 1000);
 	bool retryStatsCollection USED_WITH_LIBCURL_ONLY = false;
@@ -304,7 +313,7 @@ CitusMaintenanceDaemonMain(Datum main_arg)
 	LWLockAcquire(&MaintenanceDaemonControl->lock, LW_EXCLUSIVE);
 
 	MaintenanceDaemonDBData *myDbData = (MaintenanceDaemonDBData *)
-										hash_search(MaintenanceDaemonDBHash, &databaseOid,
+										hash_search(MaintenanceDaemonDBHash, databaseName,
 													HASH_FIND, NULL);
 	if (!myDbData)
 	{
@@ -315,6 +324,7 @@ CitusMaintenanceDaemonMain(Datum main_arg)
 		 * to properly add it to the hash.
 		 */
 
+		elog(LOG, "!myDbData");
 		proc_exit(0);
 	}
 
@@ -327,6 +337,7 @@ CitusMaintenanceDaemonMain(Datum main_arg)
 		 * In that case, the first one stays and the last one exits.
 		 */
 
+		elog(LOG, "Another maintenance daemon is running.");
 		proc_exit(0);
 	}
 
@@ -370,11 +381,14 @@ CitusMaintenanceDaemonMain(Datum main_arg)
 	error_context_stack = &errorCallback;
 
 
-	elog(LOG, "starting maintenance daemon on database %u user %u",
+	elog(LOG, "starting maintenance daemon on database %s user %u",
-		 databaseOid, myDbData->userOid);
+		 databaseName, myDbData->userOid);
 
 	/* connect to database, after that we can actually access catalogs */
-	BackgroundWorkerInitializeConnectionByOid(databaseOid, myDbData->userOid, 0);
+	BackgroundWorkerInitializeConnection(databaseName, NULL, BGWORKER_BYPASS_ALLOWCONN);
+
+        elog(LOG, "BackgroundWorkerInitializeConnection %s DBId %u userid %u",
+                 databaseName, MyDatabaseId, GetAuthenticatedUserId());
 
 	/* make worker recognizable in pg_stat_activity */
 	pgstat_report_appname("Citus Maintenance Daemon");
@@ -383,7 +397,7 @@ CitusMaintenanceDaemonMain(Datum main_arg)
 	 * Terminate orphaned metadata sync daemons spawned from previously terminated
 	 * or crashed maintenanced instances.
 	 */
-	SignalMetadataSyncDaemon(databaseOid, SIGTERM);
+	SignalMetadataSyncDaemon(MyDatabaseId, SIGTERM);
 
 	/* enter main loop */
 	while (!got_SIGTERM)
@@ -773,8 +787,7 @@ CitusMaintenanceDaemonMain(Datum main_arg)
 										 "background task queue monitor")));
 
 					backgroundTasksQueueBgwHandle =
-						StartCitusBackgroundTaskQueueMonitor(MyDatabaseId,
+						StartCitusBackgroundTaskQueueMonitor(MyDatabaseId, myDbData->userOid);
-															 myDbData->userOid);
 
 					if (!backgroundTasksQueueBgwHandle ||
 						GetBackgroundWorkerPid(backgroundTasksQueueBgwHandle,
@@ -810,9 +823,11 @@ CitusMaintenanceDaemonMain(Datum main_arg)
 			CHECK_FOR_INTERRUPTS();
 
 			/* check for changed configuration */
+
 			if (myDbData->userOid != GetSessionUserId())
 			{
 				/* return code of 1 requests worker restart */
+				elog(LOG, "userOid != GetSessionUserId()");
 				proc_exit(1);
 			}
 
@@ -897,10 +912,10 @@ MaintenanceDaemonShmemInit(void)
 
 
 	memset(&hashInfo, 0, sizeof(hashInfo));
-	hashInfo.keysize = sizeof(Oid);
+	hashInfo.keysize = NAMEDATALEN;
 	hashInfo.entrysize = sizeof(MaintenanceDaemonDBData);
-	hashInfo.hash = tag_hash;
+	
-	int hashFlags = (HASH_ELEM | HASH_FUNCTION);
+	int hashFlags = (HASH_ELEM | HASH_STRINGS);
 
 	MaintenanceDaemonDBHash = ShmemInitHash("Maintenance Database Hash",
 											max_worker_processes, max_worker_processes,
@@ -921,12 +936,13 @@ MaintenanceDaemonShmemInit(void)
 static void
 MaintenanceDaemonShmemExit(int code, Datum arg)
 {
-	Oid databaseOid = DatumGetObjectId(arg);
+
+	char* databaseName = NameStr(*DatumGetName(arg));
 
 	LWLockAcquire(&MaintenanceDaemonControl->lock, LW_EXCLUSIVE);
 
 	MaintenanceDaemonDBData *myDbData = (MaintenanceDaemonDBData *)
-										hash_search(MaintenanceDaemonDBHash, &databaseOid,
+										hash_search(MaintenanceDaemonDBHash, &databaseName,
 													HASH_FIND, NULL);
 
 	/* myDbData is NULL after StopMaintenanceDaemon */
@@ -988,8 +1004,8 @@ static void
 MaintenanceDaemonErrorContext(void *arg)
 {
 	MaintenanceDaemonDBData *myDbData = (MaintenanceDaemonDBData *) arg;
-	errcontext("Citus maintenance daemon for database %u user %u",
+	errcontext("Citus maintenance daemon for database %s user %u",
-			   myDbData->databaseOid, myDbData->userOid);
+			   myDbData->databaseName, myDbData->userOid);
 }
 
 
@@ -1034,11 +1050,15 @@ StopMaintenanceDaemon(Oid databaseId)
 	bool found = false;
 	pid_t workerPid = 0;
 
+	StartTransactionCommand();
+	char* databaseName = get_database_name(databaseId);
+	CommitTransactionCommand();
+
 	LWLockAcquire(&MaintenanceDaemonControl->lock, LW_EXCLUSIVE);
 
 	MaintenanceDaemonDBData *dbData = (MaintenanceDaemonDBData *) hash_search(
 		MaintenanceDaemonDBHash,
-		&databaseId,
+		&databaseName,
 		HASH_REMOVE, &found);
 
 	if (found)
@@ -1064,11 +1084,12 @@ TriggerNodeMetadataSync(Oid databaseId)
 {
 	bool found = false;
 
+	char* databaseName = get_database_name(databaseId);
 	LWLockAcquire(&MaintenanceDaemonControl->lock, LW_EXCLUSIVE);
 
 	MaintenanceDaemonDBData *dbData = (MaintenanceDaemonDBData *) hash_search(
 		MaintenanceDaemonDBHash,
-		&databaseId,
+		&databaseName,
 		HASH_FIND, &found);
 	if (found)
 	{

src/include/distributed/maintenanced.h

@@ -26,7 +26,7 @@ extern void TriggerNodeMetadataSync(Oid databaseId);
 extern void InitializeMaintenanceDaemon(void);
 extern size_t MaintenanceDaemonShmemSize(void);
 extern void MaintenanceDaemonShmemInit(void);
-extern void InitializeMaintenanceDaemonBackend(void);
+extern void InitializeMaintenanceDaemonBackend(const char* databaseName, Oid userOid);
 extern bool LockCitusExtension(void);
 
 extern PGDLLEXPORT void CitusMaintenanceDaemonMain(Datum main_arg);