MT#64939 use object pool for SQL conns

Change-Id: I485159b5d9d959cf878cde752bdb0e4ff104a8ad

recording-daemon/db.c

@@ -78,8 +78,19 @@ struct db_conn {
 };
 typedef struct db_conn db_conn_t;
 
+TYPED_GQUEUE(db_conn, db_conn_t)
 
-static __thread db_conn_t *db_conn;
+static db_conn_q db_conns;
+static pthread_mutex_t db_conns_lock = PTHREAD_MUTEX_INITIALIZER;
+
+
+static void return_conn(db_conn_t *dbc) {
+	pthread_mutex_lock(&db_conns_lock);
+	t_queue_push_head(&db_conns, dbc);
+	pthread_mutex_unlock(&db_conns_lock);
+}
+
+G_DEFINE_AUTOPTR_CLEANUP_FUNC(db_conn_t, return_conn);
 
 
 static void my_stmt_close(MYSQL_STMT **st) {
@@ -91,9 +102,6 @@ static void my_stmt_close(MYSQL_STMT **st) {
 
 
 static void reset_conn(db_conn_t *dbc) {
-	if (!dbc)
-		return;
-
 	if (dbc->mysql_conn) {
 		my_stmt_close(&dbc->stm_insert_call);
 		my_stmt_close(&dbc->stm_close_call);
@@ -109,6 +117,13 @@ static void reset_conn(db_conn_t *dbc) {
 	g_free(dbc);
 }
 
+static void clear_conn(db_conn_t **dbc) {
+	if (!*dbc)
+		return;
+	reset_conn(*dbc);
+	*dbc = NULL;
+}
+
 
 INLINE int prep(db_conn_t *dbc, MYSQL_STMT **st, const char *s) {
 	*st = mysql_stmt_init(dbc->mysql_conn);
@@ -128,8 +143,14 @@ static bool db_wanted(void) {
 
 
 static db_conn_t *check_conn(void) {
-	if (db_conn)
-		return db_conn;
+	pthread_mutex_lock(&db_conns_lock);
+	if (db_conns.head) {
+		db_conn_t *ret = t_queue_pop_head(&db_conns);
+		pthread_mutex_unlock(&db_conns_lock);
+		return ret;
+	}
+	pthread_mutex_unlock(&db_conns_lock);
+
 
 	dbg("connecting to MySQL");
 
@@ -185,8 +206,6 @@ static db_conn_t *check_conn(void) {
 
 	dbg("Connection to MySQL established");
 
-	db_conn = dbc;
-
 	return dbc;
 
 err:
@@ -245,8 +264,8 @@ INLINE void my_ts(MYSQL_BIND *b, int64_t ts, double *d) {
 static bool __execute_wrap(size_t stmt_offset, MYSQL_BIND *binds, unsigned long long *auto_id) {
 	int retr = 0;
 	while (1) {
-		db_conn_t *dbc;
 		MYSQL_STMT *stmt = NULL;
+		g_autoptr(db_conn_t) dbc;
 		if (!(dbc = check_conn()))
 			goto err;
 		stmt = G_STRUCT_MEMBER(MYSQL_STMT *, dbc, stmt_offset);
@@ -270,11 +289,11 @@ err:
 			if (stmt)
 				ilog(LOG_ERR, "Failed to bind or execute prepared statement: %s",
 						mysql_stmt_error(stmt));
-			reset_conn(dbc);
+			clear_conn(&dbc);
 			return false;
 		}
 		if (retr > 2) {
-			reset_conn(dbc);
+			clear_conn(&dbc);
 			if (!(dbc = check_conn()))
 				return false;
 		}
@@ -429,9 +448,6 @@ static bool do_notify(notif_req_t *req) {
 
 	bool ok = execute_wrap(stm_close_stream, b, NULL);
 
-	// running in a thread pool, don't leave connection behind
-	reset_conn(db_conn);
-
 	return ok;
 }
 
@@ -498,8 +514,3 @@ void db_config_stream(output_t *op) {
 
 	execute_wrap(stm_config_stream, b, NULL);
 }
-
-void db_thread_end(void) {
-	reset_conn(db_conn);
-	db_conn = NULL;
-}

recording-daemon/db.h

@@ -10,7 +10,6 @@ void db_do_stream(metafile_t *mf, output_t *op, stream_t *, unsigned long ssrc);
 void db_close_stream(output_t *op);
 void db_delete_stream(metafile_t *, output_t *op);
 void db_config_stream(output_t *op);
-void db_thread_end(void);
 
 
 #endif

recording-daemon/epoll.c

@@ -35,7 +35,6 @@ void epoll_del(int fd) {
 
 static void poller_thread_end(void *ptr) {
 	mysql_thread_end();
-	db_thread_end();
 }