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Compensating transactions are also used in case where a transaction is long lived (commonly called Saga Transactions), for instance in a business process requiring user input. In such cases, data will be committed to permanent storage, but may subsequently need to be rolled back, perhaps due to the user opting to cancel the operation.
A savepoint is a way of implementing subtransactions (also known as nested transactions) within a relational database management system by indicating a point within a transaction that can be "rolled back to" without affecting any work done in the transaction before the savepoint was created. Multiple savepoints can exist within a single ...
Part of the transaction log containing transactions completed by COMMIT or ROLLBACK. Because all relational databases contains, by definition, a transaction log (most of the time based on the [ARIES algorithm [Algorithms for Recovery and Isolation Exploiting Semantics]]), the log, which is a binary file, is divided into three parts, sequentially:
The commit-request phase (or voting phase), in which a coordinator process attempts to prepare all the transaction's participating processes (named participants, cohorts, or workers) to take the necessary steps for either committing or aborting the transaction and to vote, either "Yes": commit (if the transaction participant's local portion ...
undoNextLSN: This field contains the LSN of the next log record that is to be undone for transaction that wrote the last Update Log. Commit Record notes a decision to commit a transaction. Abort Record notes a decision to abort and hence roll back a transaction. Checkpoint Record notes that a checkpoint has been made. These are used to speed up ...
A complete schedule is one that contains either an abort (a.k.a. rollback) or commit action for each of its transactions. A transaction's last action is either to commit or abort. To maintain atomicity, a transaction must undo all its actions if it is aborted.
This includes transactions that completed after this transaction's start time, and optionally, transactions that are still active at validation time. Commit/Rollback: If there is no conflict, make all changes take effect. If there is a conflict, resolve it, typically by aborting the transaction, although other resolution schemes are possible.
Cursors are usually closed automatically at the end of a transaction, i.e. when a COMMIT or ROLLBACK (or an implicit termination of the transaction) occurs. That behavior can be changed if the cursor is declared using the WITH HOLD clause (the default is WITHOUT HOLD). A holdable cursor is kept open over COMMIT and closed upon ROLLBACK.