lib-sql: pgsql - Keep a persistent cache of used sql databases

diff --git a/src/lib-sql/driver-pgsql.c b/src/lib-sql/driver-pgsql.c
index a8280bedc29a1b614580e7ad7fe1fd4d6d157581..d8c845befb5998a9e4bf5444f082eaa7a4ddb46c 100644 (file)
--- a/src/lib-sql/driver-pgsql.c
+++ b/src/lib-sql/driver-pgsql.c
@@ -127,9 +127,18 @@ struct pgsql_transaction_context {
        bool failed:1;
 };
 
+struct pgsql_db_cache {
+       /* Contains the sqlpool connection */
+       struct sql_db *db;
+
+       const struct pgsql_settings *set;
+};
+
 extern const struct sql_db driver_pgsql_db;
 extern const struct sql_result driver_pgsql_result;
 
+static ARRAY(struct pgsql_db_cache) pgsql_db_cache;
+
 static void result_finish(struct pgsql_result *result);
 static void
 transaction_update_callback(struct sql_result *result,
@@ -406,6 +415,19 @@ static enum sql_db_flags driver_pgsql_get_flags(struct sql_db *db)
        return db->flags;
 }
 
+static struct pgsql_db_cache *
+driver_pgsql_db_cache_find(const struct pgsql_settings *set)
+{
+       struct pgsql_db_cache *cache;
+
+       array_foreach_modifiable(&pgsql_db_cache, cache) {
+               if (settings_equal(&pgsql_setting_parser_info,
+                                  set, cache->set, NULL))
+                       return cache;
+       }
+       return NULL;
+}
+
 static struct pgsql_db *
 driver_pgsql_init_common(struct event *event_parent,
                         const struct pgsql_settings *set)
@@ -438,12 +460,26 @@ driver_pgsql_init_v(struct event *event, struct sql_db **db_r,
        }
 
        if (event_get_ptr(event, SQLPOOL_EVENT_PTR) == NULL) {
-               /* Use sqlpool for managing multiple connections */
-               *db_r = driver_sqlpool_init(&driver_pgsql_db, event,
-                                           PGSQL_SQLPOOL_SET_NAME,
-                                           &set->sqlpool_hosts,
-                                           set->connection_limit);
-               settings_free(set);
+               /* See if there is already such a database */
+               struct pgsql_db_cache *cache =
+                       driver_pgsql_db_cache_find(set);
+               if (cache != NULL)
+                       settings_free(set);
+               else {
+                       /* Use sqlpool for managing multiple connections.
+                          Leave an extra reference to it, so it won't be freed
+                          while it's still in the cache array. */
+                       struct sql_db *db =
+                               driver_sqlpool_init(&driver_pgsql_db, event,
+                                                   PGSQL_SQLPOOL_SET_NAME,
+                                                   &set->sqlpool_hosts,
+                                                   set->connection_limit);
+                       cache = array_append_space(&pgsql_db_cache);
+                       cache->db = db;
+                       cache->set = set;
+               }
+               sql_ref(cache->db);
+               *db_r = cache->db;
                return 0;
        }
        /* We're being initialized by sqlpool - create a real pgsql
@@ -1477,11 +1513,19 @@ const char *driver_pgsql_version = DOVECOT_ABI_VERSION;
 
 void driver_pgsql_init(void)
 {
+       i_array_init(&pgsql_db_cache, 4);
        sql_driver_register(&driver_pgsql_db);
 }
 
 void driver_pgsql_deinit(void)
 {
+       struct pgsql_db_cache *cache;
+
+       array_foreach_modifiable(&pgsql_db_cache, cache) {
+               settings_free(cache->set);
+               sql_unref(&cache->db);
+       }
+       array_free(&pgsql_db_cache);
        sql_driver_unregister(&driver_pgsql_db);
 }