Several postgresql improvements.

- Make pgsql_conn_count count per database rather then globally.
  This means you now define the number of clients *per* database registered
  rather then the number of clients in total of all databases.

- In case a connection is in failed transaction state Kore will now
  automatically rollback the transaction before placing that connection
  back in the connection pool.

includes/pgsql.h

@@ -43,6 +43,8 @@ struct pgsql_conn {
 struct pgsql_db {
 	char			*name;
 	char			*conn_string;
+	u_int16_t		pgsql_conn_max;
+	u_int16_t		pgsql_conn_count;
 
 	LIST_ENTRY(pgsql_db)	rlist;
 };

src/pgsql.c

@@ -51,6 +51,7 @@ static void	pgsql_conn_release(struct kore_pgsql *);
 static void	pgsql_conn_cleanup(struct pgsql_conn *);
 static void	pgsql_read_result(struct kore_pgsql *);
 static void	pgsql_schedule(struct kore_pgsql *);
+static void	pgsql_rollback_state(struct kore_pgsql *, void *);
 
 static struct pgsql_conn	*pgsql_conn_create(struct kore_pgsql *,
 				    struct pgsql_db *);
@@ -62,13 +63,12 @@ static struct kore_pool			pgsql_wait_pool;
 static TAILQ_HEAD(, pgsql_conn)		pgsql_conn_free;
 static TAILQ_HEAD(, pgsql_wait)		pgsql_wait_queue;
 static LIST_HEAD(, pgsql_db)		pgsql_db_conn_strings;
-static u_int16_t			pgsql_conn_count;
+
 u_int16_t				pgsql_conn_max = PGSQL_CONN_MAX;
 
 void
 kore_pgsql_sys_init(void)
 {
-	pgsql_conn_count = 0;
 	TAILQ_INIT(&pgsql_conn_free);
 	TAILQ_INIT(&pgsql_wait_queue);
 	LIST_INIT(&pgsql_db_conn_strings);
@@ -179,7 +179,6 @@ kore_pgsql_query(struct kore_pgsql *pgsql, const char *query)
 
 	if (pgsql->flags & KORE_PGSQL_SYNC) {
 		pgsql->result = PQexec(pgsql->conn->db, query);
-
 		if ((PQresultStatus(pgsql->result) != PGRES_TUPLES_OK) &&
 		    (PQresultStatus(pgsql->result) != PGRES_COMMAND_OK)) {
 			pgsql_set_error(pgsql, PQerrorMessage(pgsql->conn->db));
@@ -290,6 +289,7 @@ kore_pgsql_register(const char *dbname, const char *connstring)
 
 	pgsqldb = kore_malloc(sizeof(*pgsqldb));
 	pgsqldb->name = kore_strdup(dbname);
+	pgsqldb->pgsql_conn_max = pgsql_conn_max;
 	pgsqldb->conn_string = kore_strdup(connstring);
 	LIST_INSERT_HEAD(&pgsql_db_conn_strings, pgsqldb, rlist);
 
@@ -432,8 +432,11 @@ kore_pgsql_getvalue(struct kore_pgsql *pgsql, int row, int col)
 static struct pgsql_conn *
 pgsql_conn_next(struct kore_pgsql *pgsql, struct pgsql_db *db)
 {
-	struct pgsql_conn	*conn;
+	PGTransactionStatusType		state;
+	struct pgsql_conn		*conn;
+	struct kore_pgsql		*rollback;
 
+rescan:
 	conn = NULL;
 
 	TAILQ_FOREACH(conn, &pgsql_conn_free, list) {
@@ -443,8 +446,36 @@ pgsql_conn_next(struct kore_pgsql *pgsql, struct pgsql_db *db)
 			break;
 	}
 
+	if (conn != NULL) {
+		state = PQtransactionStatus(conn->db);
+		if (state == PQTRANS_INERROR) {
+			conn->flags &= ~PGSQL_CONN_FREE;
+			TAILQ_REMOVE(&pgsql_conn_free, conn, list);
+
+			rollback = kore_malloc(sizeof(*rollback));
+			kore_pgsql_init(rollback);
+			kore_pgsql_bind_callback(rollback,
+			    pgsql_rollback_state, NULL);
+			rollback->flags |= KORE_PGSQL_ASYNC;
+
+			rollback->conn = conn;
+			rollback->conn->job = kore_pool_get(&pgsql_job_pool);
+			rollback->conn->job->pgsql = rollback;
+
+			if (!kore_pgsql_query(rollback, "ROLLBACK")) {
+				kore_pgsql_logerror(rollback);
+				kore_pgsql_cleanup(rollback);
+				kore_free(rollback);
+				pgsql_conn_cleanup(conn);
+				return (NULL);
+			}
+
+			goto rescan;
+		}
+	}
+
 	if (conn == NULL) {
-		if (pgsql_conn_count >= pgsql_conn_max) {
+		if (db->pgsql_conn_count >= db->pgsql_conn_max) {
 			if (pgsql->flags & KORE_PGSQL_ASYNC) {
 				pgsql_queue_add(pgsql);
 			} else {
@@ -563,7 +594,7 @@ pgsql_conn_create(struct kore_pgsql *pgsql, struct pgsql_db *db)
 	if (db == NULL || db->conn_string == NULL)
 		fatal("pgsql_conn_create: no connection string");
 
-	pgsql_conn_count++;
+	db->pgsql_conn_count++;
 
 	conn = kore_malloc(sizeof(*conn));
 	conn->job = NULL;
@@ -588,6 +619,7 @@ static void
 pgsql_conn_release(struct kore_pgsql *pgsql)
 {
 	int		fd;
+	PGresult	*result;
 
 	if (pgsql->conn == NULL)
 		return;
@@ -605,8 +637,8 @@ pgsql_conn_release(struct kore_pgsql *pgsql)
 	}
 
 	/* Drain just in case. */
-	while (PQgetResult(pgsql->conn->db) != NULL)
+	while ((result = PQgetResult(pgsql->conn->db)) != NULL)
-		;
+		PQclear(result);
 
 	pgsql->conn->job = NULL;
 	pgsql->conn->flags |= PGSQL_CONN_FREE;
@@ -625,6 +657,7 @@ static void
 pgsql_conn_cleanup(struct pgsql_conn *conn)
 {
 	struct kore_pgsql	*pgsql;
+	struct pgsql_db		*pgsqldb;
 
 	kore_debug("pgsql_conn_cleanup(): %p", conn);
 
@@ -647,7 +680,13 @@ pgsql_conn_cleanup(struct pgsql_conn *conn)
 	if (conn->db != NULL)
 		PQfinish(conn->db);
 
-	pgsql_conn_count--;
+	LIST_FOREACH(pgsqldb, &pgsql_db_conn_strings, rlist) {
+		if (strcmp(pgsqldb->name, conn->name)) {
+			pgsqldb->pgsql_conn_count--;
+			break;
+		}
+	}
+
 	kore_free(conn->name);
 	kore_free(conn);
 }
@@ -701,3 +740,20 @@ pgsql_cancel(struct kore_pgsql *pgsql)
 		PQfreeCancel(cancel);
 	}
 }
+
+static void
+pgsql_rollback_state(struct kore_pgsql *pgsql, void *arg)
+{
+	switch (pgsql->state) {
+	case KORE_PGSQL_STATE_ERROR:
+		kore_pgsql_logerror(pgsql);
+		kore_pgsql_cleanup(pgsql);
+		break;
+	case KORE_PGSQL_STATE_COMPLETE:
+		kore_pgsql_cleanup(pgsql);
+		break;
+	default:
+		kore_pgsql_continue(pgsql);
+		break;
+	}
+}