[DERBY-2490] Clarify transaction management in LanguageConnectionContext.

• Type: Sub-task
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: SQL
• Labels: derby_triage10_10
• Urgency: Normal
• Assignee: Unassigned
• Reporter: Daniel John Debrunner
• Created: 26/Mar/07 23:56
• Updated: 02/Oct/12 05:20

Description

LanguageConnectionContext has these four methods (as well as other commit/rollback methods) to manage transactions and specifically nested transactions.

void beginNestedTransaction(boolean readOnly) throws StandardException;
void commitNestedTransaction() throws StandardException;
TransactionController getTransactionCompile();
TransactionController getTransactionExecute();

getTransactionCompile() returns the same as getTransactionExecute() if not in a nested transaction.

nested transactions started out as "compile time" transactions but are now used at runtime, for example in permission lookup and identity columns,
thus the name getTransactionCompile() can confuse readers.

A cleaner api might be to just have a single getTransaction() method that returns the current transaction, which is main transaction (non-nested) except
between calls to
beginNestedTransaction()
commitNestedTransaction()

I think that is the logic today, one one transaction is active, either the nested one of the main one.