Help Center/ GaussDB/ Feature Guide(Distributed_3.x)/ Storage Engine/ Ustore/ Storage Format/ Relation/ Page-based Row Consistency Read (PbRCR) Heap Multi-Version Management
Updated on 2024-05-20 GMT+08:00

Page-based Row Consistency Read (PbRCR) Heap Multi-Version Management

  1. The heap multi-version management is row-level multi-version management based on tuples.
  2. When a transaction modifies a record, historical data is recorded in an undo row.
  3. The address of the generated undo row (zone_id, block no, page offset) is recorded in td_id in a tuple.
  4. New data is overwritten to the heap page.
  5. Each data modification generates an undo row. Undo rows with the same record is connected by block_prev.