Function PAG_release_pages

src/jrd/pag.cpp:1577–1666

void PAG_release_pages(thread_db* tdbb, USHORT pageSpaceID, int cntRelease,
		const ULONG* pgNums, const ULONG prior_page)
{
/**************************************
 *
 *	P A G _ r e l e a s e _ p a g e s
 *
 **************************************
 *
 * Functional description
 *	Release a few pages to the free page page.
 *
 **************************************/

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

	PageManager& pageMgr = dbb->dbb_page_manager;
	PageSpace* pageSpace = pageMgr.findPageSpace(pageSpaceID);
	fb_assert(pageSpace);

	WIN pip_window(pageSpaceID, -1);
	page_inv_page* pages = NULL;
	ULONG sequence = 0;

#ifdef VIO_DEBUG
	string dbg = "PAG_release_pages:  about to release pages: ";
#endif

	for (int i = 0; i < cntRelease; i++)
	{
#ifdef VIO_DEBUG
		if (i > 0)
			dbg.append(", ");

		char num[16];
		_ltoa_s(pgNums[i], num, sizeof(num), 10);
		dbg.append(num);
#endif

		const ULONG seq = pgNums[i] / pageMgr.pagesPerPIP;

		if (!pages || seq != sequence)
		{
			if (pages)
			{
				pageSpace->pipHighWater.exchangeLower(sequence);
				if (pages->pip_extent < pageMgr.pagesPerPIP)
					pageSpace->pipWithExtent.exchangeLower(sequence);

				CCH_RELEASE(tdbb, &pip_window);
			}

			sequence = seq;
			pip_window.win_page = (sequence == 0) ?
				pageSpace->pipFirst : sequence * pageMgr.pagesPerPIP - 1;