File Structure

To query whether the current rollback segment is stored in page or segment-page mode, query the system catalog. Currently, only the page mode is supported.

Example:

gaussdb=# SELECT * FROM gs_global_config WHERE name LIKE '%undostoragetype%';
      name       |  value
-----------------+---------
 undostoragetype | page
(1 row)

• When the rollback segment is stored by page:
  • Structure of the file where the txn page is stored

    $node_dir/undo/{permanent|unlogged|temp}/$undo_zone_id.meta.$segno

  • Structure of the file where the undo row is stored

    $node_dir/undo/{permanent|unlogged|temp}/$undo_zone_id.$segno