internal CompressedRecordPage GetCompressedRecordPage(PagePointer loc, CompressionContext compression)
{
if (compression.CompressionLevel == CompressionLevel.None)
{
throw new ArgumentException("Can't load compressed page with a compression level of none.");
}
Debug.WriteLine("Loading compressed record page " + loc);
return(new CompressedRecordPage(GetPageBytes(loc), compression, this));
}
internal GamPage GetGamPage(PagePointer loc)
{
Debug.WriteLine("Loading GAM Page " + loc);
if (loc.PageID % 511230 != 2)
{
throw new ArgumentException("Invalid GAM index: " + loc.PageID);
}
return(new GamPage(GetPageBytes(loc), this));
}
internal PfsPage GetPfsPage(PagePointer loc)
{
Debug.WriteLine("Loading PFS Page " + loc);
// We know PFS pages are present every 8088th page, except for the very first one
if (loc.PageID != 1 && loc.PageID % 8088 != 0)
{
throw new ArgumentException("Invalid PFS index: " + loc.PageID);
}
return(new PfsPage(GetPageBytes(loc), this));
}
/// <summary>
/// Starts at the data page (loc) and follows the NextPage pointer chain till the end.
/// </summary>
internal IEnumerable <Row> ScanLinkedNonclusteredIndexPages(PagePointer loc, Row schema, CompressionContext compression)
{
while (loc != PagePointer.Zero)
{
var page = Database.GetNonclusteredIndexPage(loc);
foreach (var dr in page.GetEntities(schema, compression))
{
yield return(dr);
}
loc = page.Header.NextPage;
}
}
/// <summary>
/// Starts at the data page (loc) and follows the NextPage pointer chain till the end.
/// </summary>
internal IEnumerable <Row> ScanLinkedDataPages(PagePointer loc, DataExtractorHelper schema,
CompressionContext compression, bool isSysTable)
{
while (PagePointer.Zero != loc && loc != null && loc.PageID > 0)
{
var recordParser = RecordEntityParser.CreateEntityParserForPage(loc, compression, Database, isSysTable);
foreach (var dr in recordParser.GetEntities(schema))
{
yield return(dr);
}
loc = recordParser.NextPage;
}
}
internal IamPage GetIamPage(PagePointer loc, bool useCache)
{
Debug.WriteLine("Loading IAM Page " + loc);
return(new IamPage(GetPageBytes(loc, useCache), this));
}
internal TextMixPage GetTextMixPage(PagePointer loc)
{
Debug.WriteLine("Loading TextMix Page " + loc);
return(new TextMixPage(GetPageBytes(loc, false), this));
}
internal ClusteredIndexPage GetClusteredIndexPage(PagePointer loc, bool isSysTable)
{
Debug.WriteLine("Loading Clustered Index Page " + loc);
return(new ClusteredIndexPage(GetPageBytes(loc, isSysTable), this));
}
internal NonclusteredIndexPage GetNonclusteredIndexPage(PagePointer loc)
{
Debug.WriteLine("Loading Nonclustered Index Page " + loc);
return(new NonclusteredIndexPage(GetPageBytes(loc), this));
}
internal FileHeaderPage GetFileHeaderPage(PagePointer loc)
{
Debug.WriteLine("Loading File Header Page");
return(new FileHeaderPage(GetPageBytes(loc), this));
}
internal Page GetPage(PagePointer loc)
{
Debug.WriteLine("Loading Generic Page " + loc);
return(new Page(GetPageBytes(loc), this));
}
private byte[] GetPageBytes(PagePointer pagePointer, bool putResultsToCache = true)
{
return(_bufferManager.GetPageBytes(pagePointer.FileID, pagePointer.PageID, putResultsToCache));
}
internal PrimaryRecordPage GetPrimaryRecordPage(PagePointer loc, CompressionContext compression, bool isSysTable = true)
{
Debug.WriteLine("Loading Primary Record Page " + loc);
return(new PrimaryRecordPage(GetPageBytes(loc, isSysTable), compression, this));
}
public ExtentPointer(PagePointer start)
{
StartPage = start;
EndPage = new PagePointer(start.FileID, start.PageID + 7);
}
/// <summary>
/// Scans a linked list of pages returning an IEnumerable of typed rows with data & schema
/// </summary>
internal IEnumerable <TDataRow> ScanLinkedDataPages <TDataRow>(PagePointer loc, CompressionContext compression) where TDataRow : Row, new()
{
return(ScanLinkedDataPages(loc, new DataExtractorHelper(new TDataRow()), compression, true).Cast <TDataRow>());
}
/// <summary>
/// Scans a heap beginning from the provided IAM page and onwards.
/// </summary>
private IEnumerable <Row> ScanHeap(PagePointer loc, DataExtractorHelper schema, CompressionContext compression,
bool isSysTable)
{
// Traverse the linked list of IAM pages until the tail pointer is zero
while (loc != PagePointer.Zero)
{
// Before scanning, check that the IAM page itself is allocated
var pfsPage = Database.GetPfsPage(PfsPage.GetPfsPointerForPage(loc));
// If IAM page isn't allocated, there's nothing to return
if (!pfsPage.GetPageDescription(loc.PageID).IsAllocated)
{
yield break;
}
var iamPage = Database.GetIamPage(loc, isSysTable);
// Create an array with all of the header slot pointers
var iamPageSlots = new []
{
iamPage.Slot0,
iamPage.Slot1,
iamPage.Slot2,
iamPage.Slot3,
iamPage.Slot4,
iamPage.Slot5,
iamPage.Slot6,
iamPage.Slot7
};
// Loop each header slot and yield the results, provided the header slot is allocated
foreach (var slot in iamPageSlots.Where(x => x != PagePointer.Zero))
{
var recordParser = RecordEntityParser.CreateEntityParserForPage(slot, compression, Database, isSysTable);
foreach (var dr in recordParser.GetEntities(schema))
{
yield return(dr);
}
}
// Then loop through allocated extents and yield results
foreach (var extent in iamPage.GetAllocatedExtents())
{
// Get PFS page that tracks this extent
var pfs = Database.GetPfsPage(PfsPage.GetPfsPointerForPage(extent.StartPage));
foreach (var pageLoc in extent.GetPagePointers())
{
// Check if page is allocated according to PFS page
var pfsDescription = pfs.GetPageDescription(pageLoc.PageID);
if (!pfsDescription.IsAllocated)
{
continue;
}
var recordParser = RecordEntityParser.CreateEntityParserForPage(pageLoc, compression, Database, isSysTable);
foreach (var dr in recordParser.GetEntities(schema))
{
yield return(dr);
}
}
}
// Update current IAM chain location to the tail pointer
loc = iamPage.Header.NextPage;
}
}
