Function SDW_dump_pages

src/jrd/sdw.cpp:422–523

void SDW_dump_pages(thread_db* tdbb)
{
/**************************************
 *
 *	S D W _ d u m p _ p a g e s
 *
 **************************************
 *
 * Functional description
 *	Look for any shadow files that haven't been written yet.
 *	Fetch pages from the database and write them
 *	to all unwritten shadow files.
 *
 **************************************/
	SET_TDBB(tdbb);
	Database* dbb = tdbb->getDatabase();
	SyncLockGuard guard(&dbb->dbb_shadow_sync, SYNC_EXCLUSIVE, "SDW_dump_pages");

	gds__log("conditional shadow dumped for database %s", dbb->dbb_filename.c_str());
	const SLONG max = PAG_last_page(tdbb);

	// mark the first shadow in the list because we don't
	// want to start shadowing to any files that are added
	// while we are in the middle of dumping pages

	// none of these pages should need any alteration
	// since header pages for extend files are not handled at this level
	WIN window(DB_PAGE_SPACE, -1);
	window.win_flags = WIN_large_scan;
	window.win_scans = 1;

	for (SLONG page_number = HEADER_PAGE + 1; page_number <= max; page_number++)
	{
#ifdef SUPERSERVER_V2
		if (!(page_number % dbb->dbb_prefetch_sequence))
		{
			SLONG pages[PREFETCH_MAX_PAGES];

			SLONG number = page_number;
			SLONG i = 0;
			while (i < dbb->dbb_prefetch_pages && number <= max) {
				pages[i++] = number++;
			}

			CCH_PREFETCH(tdbb, pages, i);
		}
#endif
		for (Shadow* shadow = dbb->dbb_shadow; shadow; shadow = shadow->sdw_next)
		{
			if (!(shadow->sdw_flags & (SDW_INVALID | SDW_dumped)))
			{
				window.win_page = page_number;

				// when copying a database, it is possible that there are some pages defined
				// in the pip that were never actually written to disk, in the case of a faked
				// page which was never written to disk because of a rollback; to prevent
				// checksum errors on this type of page, don't check for checksum when the
				// page type is 0