Function SDW_notify

src/jrd/sdw.cpp:674–728

void SDW_notify(thread_db* tdbb)
{
/**************************************
 *
 *	S D W _ n o t i f y
 *
 **************************************
 *
 * Functional description
 *	Notify other processes that there has been
 *	a shadow added.
 *
 **************************************/
	SET_TDBB(tdbb);
	Database* dbb = tdbb->getDatabase();
	CHECK_DBB(dbb);

	SyncLockGuard guard(&dbb->dbb_shadow_sync, SYNC_EXCLUSIVE, "SDW_notify");

	// get current shadow lock count from database header page --
	// note that since other processes need the header page to issue locks
	// on the shadow count, this is effectively an uninterruptible operation

	WIN window(HEADER_PAGE_NUMBER);
	header_page* header = (header_page*) CCH_FETCH(tdbb, &window, LCK_write, pag_header);
	CCH_MARK_MUST_WRITE(tdbb, &window);

	// get an exclusive lock on the current shadowing semaphore to
	// notify other processes to find my shadow -- if we have a shared
	// on it already, convert to exclusive

	Lock* lock = dbb->dbb_shadow_lock;

	if (lock->lck_physical == LCK_SR)
	{
		if (lock->getKey() != header->hdr_shadow_count)
			BUGCHECK(162);		// msg 162 shadow lock not synchronized properly
		LCK_convert(tdbb, lock, LCK_EX, LCK_WAIT);
	}
	else
	{
		lock->setKey(header->hdr_shadow_count);
		LCK_lock(tdbb, lock, LCK_EX, LCK_WAIT);
	}

	LCK_release(tdbb, lock);

	// now get a shared lock on the incremented shadow count to ensure that
	// we will get notification of the next shadow add

	lock->setKey(++header->hdr_shadow_count);
	LCK_lock(tdbb, lock, LCK_SR, LCK_WAIT);

	CCH_RELEASE(tdbb, &window);
}


bool SDW_rollover_to_shadow(thread_db* tdbb, jrd_file* file, const bool inAst)