Function TRA_snapshot_state

src/jrd/tra.cpp:1578–1694

int TRA_snapshot_state(thread_db* tdbb, const jrd_tra* trans, TraNumber number, CommitNumber* snapshot)
{
/**************************************
 *
 *	T R A _ s n a p s h o t _ s t a t e
 *
 **************************************
 *
 * Functional description
 *	Get the state of a numbered transaction when a
 *	transaction started.
 *
 **************************************/

	SET_TDBB(tdbb);
	Database* dbb = tdbb->getDatabase();
	CHECK_DBB(dbb);

	Attachment* att = tdbb->getAttachment();

	// Inhibit intermediate GC by default

	if (snapshot)
		*snapshot = CN_ACTIVE;

	if (number == trans->tra_number)
		return tra_us;

	// If the transaction is older than the oldest
	// interesting transaction, it must be committed.

	if (number < trans->tra_oldest)
	{
		if (snapshot)
			*snapshot = att->att_active_snapshots.getSnapshotForVersion(CN_PREHISTORIC);
		return tra_committed;
	}

	// If the transaction is the system transaction, it is considered committed.

	if (number == TRA_system_transaction)
	{
		if (snapshot)
			*snapshot = att->att_active_snapshots.getSnapshotForVersion(CN_PREHISTORIC);
		return tra_committed;
	}

	// Determine transaction state and commit number if any

	int state;
	CommitNumber stateCn = CN_PREHISTORIC;

	if (TipCache* tip_cache = dbb->dbb_tip_cache)
	{
		stateCn = tip_cache->snapshotState(tdbb, number);
		switch (stateCn)
		{
			case CN_ACTIVE: