refs #5467, do checkpoitn at end of tokudb_add_index

git-svn-id: file:///svn/mysql/tokudb-engine/tokudb-engine@47745 c7de825b-a66e-492c-adef-691d508d4ae1

storage/tokudb/ha_tokudb.cc

@@ -7694,6 +7694,17 @@ int ha_tokudb::tokudb_add_index(
     }
     pthread_mutex_unlock(&share->mutex);
 
+    // the transaction that does either a bulk load or a hot index
+    // will need to do a checkpoint during commit, which may be
+    // expensive. This may block other threads because the commit
+    // takes place when MySQL's metadata lock is held. So,
+    // reduce the time it takes for that checkpoint to happen,
+    // we run a checkpoint right now.
+    error = db_env->txn_checkpoint(db_env, 0, 0, 0);
+    if (error) {
+        goto cleanup;
+    }
+    
     error = 0;
 cleanup:
 #ifdef HA_TOKUDB_HAS_THD_PROGRESS