Berkeley DB

Nested Transactions

Berkeley DB provides support for nested transactions. Nested transactions allow an application to decompose a large or long-running transaction into smaller units that may be independently aborted.

Normally, when beginning a transaction, the application will pass a NULL value for the parent argument to txn_begin. If, however, the parent argument is a DB_TXN handle, the newly created transaction will be treated as a nested transaction within the parent. Transactions may nest arbitrarily deeply. For the purposes of this discussion, transactions created with a parent identifier will be called child transactions.

Once a transaction becomes a parent, as long as any of its child transactions are unresolved (that is, they have neither ...