Efficient Database Undo / Redo Logging

摘要

Log records are accessed as part of a database operation in a database. The log records log insert, update, and delete operations in the database and include, for each row, a row position, a fragment identifier (ID), and a row ID. Thereafter, as part of the database operation, rows specified by the log records are located by: using the fragment identifier and the row position within the corresponding record of the log if the fragment with the corresponding fragment identifier is still available, otherwise, using the row identifier within the corresponding record of the log to look up the row position in an index of a corresponding row identifier column. The database operation is then finalized using the located rows. Related apparatus, systems, techniques and articles are also described.

主权项

1. A method comprising:
accessing, as part of a database operation in a database, log records logging insert, update, and delete operations in the database, the log records including, for each row, a row position, a fragment identifier (ID), and a row ID, the row position representing an offset of the corresponding row in an array, the fragment ID representing an immutable identifier of a fragment of a table corresponding to the row, the row ID representing an immutable identifier of the row; locating, as part of the database operation, rows specified by the log records by:
using the fragment identifier and the row position within the corresponding record of the log if the fragment with the corresponding fragment identifier is still available, otherwise,using the row identifier within the corresponding record of the log to look up the row position in an index of a corresponding row identifier column; and finalizing the database operation using the located rows.