Recovery Protocol for Nested Transactions Using Write-Ahead Logging
Original Publication Date: 1988-Sep-01
Included in the Prior Art Database: 2005-Feb-15
A recovery protocol for nested transactions (NTs) is described which allows a subtransaction to run concurrently with its children, parent, siblings, and nonrelatives. In this NT recovery method, each subtransaction does its own logging. The log records of each subtransaction are linked together in a backward chain (BC). When a subtransaction is being committed, the commit record for the subtransaction is written so that it is part of the BC of the parent subtransaction. The record also contains a pointer to the last log record written by the committing subtransaction. A compensation log record (CLR) of a subtransaction contains the address of the next record of that subtransaction that is to be undone.