Function VIO_chase_record_version

src/jrd/vio.cpp:1111–1684

bool VIO_chase_record_version(thread_db* tdbb, record_param* rpb,
							  jrd_tra* transaction, MemoryPool* pool,
							  bool writelock, bool noundo)
{
/**************************************
 *
 *	V I O _ c h a s e _ r e c o r d _ v e r s i o n
 *
 **************************************
 *
 * Functional description
 *	This is the key routine in all of JRD.  Given a record, determine
 *	what the version, if any, is appropriate for this transaction.  This
 *	is primarily done by playing with transaction numbers.  If, in the
 *	process, a record is found that requires garbage collection, by all
 *	means garbage collect it.
 *
 **************************************/
	SET_TDBB(tdbb);
	Database* const dbb = tdbb->getDatabase();
	Jrd::Attachment* const attachment = transaction->tra_attachment;
	jrd_rel* const relation = rpb->rpb_relation;

	const bool gcPolicyCooperative = dbb->dbb_flags & DBB_gc_cooperative;
	const bool gcPolicyBackground = dbb->dbb_flags & DBB_gc_background;
	const TraNumber oldest_snapshot = relation->isTemporary() ?
		attachment->att_oldest_snapshot : transaction->tra_oldest_active;

#ifdef VIO_DEBUG
	VIO_trace(DEBUG_TRACE_ALL,
		"VIO_chase_record_version (rel_id %u, record_param %" QUADFORMAT"d, transaction %"
		SQUADFORMAT", pool %p)\n",
		relation->rel_id,
		rpb->rpb_number.getValue(), transaction ? transaction->tra_number : 0,
		(void*) pool);

	VIO_trace(DEBUG_TRACE_ALL_INFO,
		"   record  %" SLONGFORMAT":%d, rpb_trans %" SQUADFORMAT
		", flags %d, back %" SLONGFORMAT":%d, fragment %" SLONGFORMAT":%d\n",
		rpb->rpb_page, rpb->rpb_line, rpb->rpb_transaction_nr,
		rpb->rpb_flags, rpb->rpb_b_page, rpb->rpb_b_line,
		rpb->rpb_f_page, rpb->rpb_f_line);
#endif

	CommitNumber current_snapshot_number;
	bool int_gc_done = (attachment->att_flags & ATT_no_cleanup);

	int state = TRA_snapshot_state(tdbb, transaction, rpb->rpb_transaction_nr, &current_snapshot_number);

	// Reset (if appropriate) the garbage collect active flag to reattempt the backout

	if (rpb->rpb_flags & rpb_gc_active)
		checkGCActive(tdbb, rpb, state);

	// Take care about modifications performed by our own transaction

	rpb->rpb_runtime_flags &= ~RPB_CLEAR_FLAGS;
	int forceBack = 0;