addresses 962

grab table locks when doing a scan of a secondary index

git-svn-id: file:///svn/mysql/tokudb-engine/src@4792 c7de825b-a66e-492c-adef-691d508d4ae1

storage/tokudb/ha_tokudb.cc

@@ -2194,6 +2194,31 @@ int ha_tokudb::delete_row(const uchar * record) {
     TOKUDB_DBUG_RETURN(error);
 }
 
+//
+// Notification that a scan of entire secondary table is about
+// to take place. Will pre acquire table read lock
+// Returns:
+//      0 on success
+//      error otherwise
+//
+int ha_tokudb::prepare_index_scan() {
+    int error;
+    DB* db = share->key_file[active_index];
+    error = db->pre_acquire_read_lock(
+        db, 
+        transaction, 
+        db->dbt_neg_infty(), db->dbt_neg_infty(), 
+        db->dbt_pos_infty(), db->dbt_pos_infty()
+        );
+    if (error) { last_cursor_error = error; goto cleanup; }
+
+    range_lock_grabbed = true;
+    error = 0;
+cleanup:
+    return error;
+}
+
+
 //
 // Initializes local cursor on DB with index keynr
 // Parameters:

storage/tokudb/ha_tokudb.h

@@ -227,6 +227,7 @@ public:
     int update_row(const uchar * old_data, uchar * new_data);
     int delete_row(const uchar * buf);
 
+    int prepare_index_scan();
     int index_init(uint index, bool sorted);
     int index_end();
     int index_read(uchar * buf, const uchar * key, uint key_len, enum ha_rkey_function find_flag);