Function adjust_scan_count

src/jrd/cch.cpp:2548–2589

static void adjust_scan_count(WIN* window, bool mustRead)
{
/**************************************
 *
 *	a d j u s t _ s c a n _ c o u n t
 *
 **************************************/
	BufferDesc* bdb = window->win_bdb;

	// If a page was read or prefetched on behalf of a large scan
	// then load the window scan count into the buffer descriptor.
	// This buffer scan count is decremented by releasing a buffer
	// with CCH_RELEASE_TAIL.

	// Otherwise zero the buffer scan count to prevent the buffer
	// from being queued to the LRU tail.

	if (window->win_flags & WIN_large_scan)
	{
		if (mustRead || (bdb->bdb_flags & BDB_prefetch) || bdb->bdb_scan_count < 0)
			bdb->bdb_scan_count = window->win_scans;
	}
	else if (window->win_flags & WIN_garbage_collector)
	{
		if (mustRead)
			bdb->bdb_scan_count = -1;

		if (bdb->bdb_flags & BDB_garbage_collect)
			window->win_flags |= WIN_garbage_collect;
	}
	else if (window->win_flags & WIN_secondary)
	{
		if (mustRead)
			bdb->bdb_scan_count = -1;
	}
	else
	{
		bdb->bdb_scan_count = 0;
		if (bdb->bdb_flags & BDB_garbage_collect)
			bdb->bdb_flags &= ~BDB_garbage_collect;
	}
}


static int blocking_ast_bdb(void* ast_object)