[t:4695], make handler changes to get this working. Tests remain

git-svn-id: file:///svn/mysql/tokudb-engine/tokudb-engine@41776 c7de825b-a66e-492c-adef-691d508d4ae1

storage/tokudb/ha_tokudb.cc

@@ -7717,9 +7717,8 @@ int ha_tokudb::add_index(TABLE *table_arg, KEY *key_info, uint num_of_keys, hand
     bool incremented_numDBs = false;
     bool modified_DBs = false;
 
-    DB_TXN* txn = NULL;
-    error = db_env->txn_begin(db_env, 0, &txn, 0);
-    if (error) { goto cleanup; }
+    // transaction is created in prepare_for_alter
+    DB_TXN* txn = transaction;
 
     error = tokudb_add_index(
         table_arg,
@@ -7735,7 +7734,6 @@ int ha_tokudb::add_index(TABLE *table_arg, KEY *key_info, uint num_of_keys, hand
     if (error) {
         if (txn) {
             restore_add_index(table_arg, num_of_keys, incremented_numDBs, modified_DBs);
-            abort_txn(txn);
         }
     } else {
         *add = new ha_tokudb_add_index(table_arg, key_info, num_of_keys, txn, incremented_numDBs, modified_DBs);
@@ -7760,12 +7758,12 @@ int ha_tokudb::final_add_index(handler_add_index *add_arg, bool commit) {
 
     int error = 0;
 
-    if (commit) {
-        commit_txn(txn, 0);
-    } else {
+    if (!commit) {
         restore_add_index(table, num_of_keys, incremented_numDBs, modified_DBs);
-        abort_txn(txn);
     }
+    // transaction does not need to be committed,
+    // we depend on MySQL to rollback the transaction
+    // by calling tokudb_rollback
     TOKUDB_DBUG_RETURN(error);
 }