Function retain_context

src/jrd/tra.cpp:2577–2708

static void retain_context(thread_db* tdbb, jrd_tra* transaction, bool commit, int state)
{
/**************************************
 *
 *	r e t a i n _ c o n t e x t
 *
 **************************************
 *
 * Functional description
 *	If 'commit' flag is true, commit the transaction,
 *	else rollback the transaction.
 *
 *	Commit/rollback a transaction while preserving the
 *	context, in particular, its snapshot. The
 *	trick is to insure that the transaction's
 *	oldest active is seen by other transactions
 *	simultaneously starting up.
 *
 **************************************/
	SET_TDBB(tdbb);
	Database* dbb = tdbb->getDatabase();
	CHECK_DBB(dbb);

	// All savepoints must already be released in TRA_commit/TRA_rollback
	fb_assert(!transaction->tra_save_point);

	// The new transaction needs to remember the 'commit-retained' transaction
	// because it must see the operations of the 'commit-retained' transaction and
	// its snapshot doesn't contain these operations.

	if (commit)
		TBM_SET(tdbb->getDefaultPool(), &transaction->tra_commit_sub_trans, transaction->tra_number);

	// Create a new transaction lock, inheriting oldest active from transaction being committed.

	WIN window(DB_PAGE_SPACE, -1);
	TraNumber new_number;
#ifdef SUPERSERVER_V2
	new_number = bump_transaction_id(tdbb, &window);
#else
	if (dbb->readOnly())
		new_number = dbb->generateTransactionId();
	else
	{
		const bool dontWrite = (dbb->dbb_flags & DBB_shared) &&
			(transaction->tra_flags & TRA_readonly);

		const header_page* const header = bump_transaction_id(tdbb, &window, dontWrite);
		new_number = Ods::getNT(header);
	}
#endif

	Lock* new_lock = NULL;
	Lock* old_lock = transaction->tra_lock;
	if (old_lock)
	{
		new_lock = FB_NEW_RPT(*tdbb->getDefaultPool(), 0) Lock(tdbb, sizeof(TraNumber), LCK_tra);
		new_lock->setKey(new_number);