FS-12050: [Core] Fix DataBase Handle (DBH) cache logic

diff --git a/src/switch_core_sqldb.c b/src/switch_core_sqldb.c
index 51fde6ebdf745e6cfad7c411919297acefdefcf6..4bae77fbfa87d32f395fd56cea79179aadb59aed 100644 (file)
--- a/src/switch_core_sqldb.c
+++ b/src/switch_core_sqldb.c
@@ -179,18 +179,27 @@ static switch_cache_db_handle_t *get_handle(const char *db_str, const char *user
 
        switch_mutex_lock(sql_manager.dbh_mutex);
 
+       /* First loop allows a thread to use a handle multiple times sumiltaneously
+          but only if that handle is in use by the same thread. In that case use_count will be incremented.
+          This allows SQLite to read and write within a single thread, giving the same handle for both operations.
+       */
        for (dbh_ptr = sql_manager.handle_pool; dbh_ptr; dbh_ptr = dbh_ptr->next) {
-               if (dbh_ptr->thread_hash == thread_hash && dbh_ptr->hash == hash && !dbh_ptr->use_count &&
+               if (dbh_ptr->thread_hash == thread_hash && dbh_ptr->hash == hash &&
                        !switch_test_flag(dbh_ptr, CDF_PRUNE) && switch_mutex_trylock(dbh_ptr->mutex) == SWITCH_STATUS_SUCCESS) {
                        r = dbh_ptr;
+                       break;
                }
        }
 
        if (!r) {
+               /* If a handle idles, take it and associate with the thread.
+                  If a handle is in use, skip and create new one.
+               */
                for (dbh_ptr = sql_manager.handle_pool; dbh_ptr; dbh_ptr = dbh_ptr->next) {
-                       if (dbh_ptr->hash == hash && (dbh_ptr->type != SCDB_TYPE_DATABASE_INTERFACE || !dbh_ptr->use_count) && !switch_test_flag(dbh_ptr, CDF_PRUNE) &&
+                       if (dbh_ptr->hash == hash && !dbh_ptr->use_count && !switch_test_flag(dbh_ptr, CDF_PRUNE) &&
                                switch_mutex_trylock(dbh_ptr->mutex) == SWITCH_STATUS_SUCCESS) {
                                r = dbh_ptr;
+                               r->thread_hash = thread_hash;
                                break;
                        }
                }
@@ -200,8 +209,6 @@ static switch_cache_db_handle_t *get_handle(const char *db_str, const char *user
                r->use_count++;
                r->total_used_count++;
                sql_manager.total_used_handles++;
-               r->hash = switch_ci_hashfunc_default(db_str, &hlen);
-               r->thread_hash = thread_hash;
                switch_set_string(r->last_user, user_str);
        }
 
@@ -349,9 +356,7 @@ SWITCH_DECLARE(void) switch_cache_db_release_db_handle(switch_cache_db_handle_t
                (*dbh)->io_mutex = NULL;
 
                if ((*dbh)->use_count) {
-                       if (--(*dbh)->use_count == 0) {
-                               (*dbh)->thread_hash = 1;
-                       }
+                       --(*dbh)->use_count;
                }
                switch_mutex_unlock((*dbh)->mutex);
                sql_manager.total_used_handles--;