/// <summary>
/// This is used during the commit of a transaction. It takes all the new
/// page versions that were constructed during the commit merge and adds them
/// to a dictionary of pages
/// </summary>
/// <param name="pages">The dictionary of pages to add to</param>
public void AddToPages(PageHeadCollection pages)
{
foreach (var pageVersionElement in _pageVersions)
{
var pageVersion = pageVersionElement.Data;
var pageNumber = pageVersion.Page.PageNumber;
var pageHead = pages.GetPageHead(pageNumber, CacheHints.ForUpdate);
pageHead.AddVersion(pageVersion);
}
}
public void AddUpdates(IEnumerable <PageUpdate> updates, PageHeadCollection pages)
{
EnsureUpdates();
var start = Updates.Count;
int end;
lock (Updates)
{
Updates.AddRange(updates.OrderBy(u => u.SequenceNumber).Select(u => { u.SequenceNumber += (uint)start; return(u); }));
end = Updates.Count;
}
for (var i = start; i < end; i++)
{
PageUpdate update;
lock (Updates) update = Updates[i];
IPage modifiedPage = null;
try
{
lock (Transaction)
{
modifiedPage = GetModifiedPage(update.PageNumber);
if (modifiedPage == null)
{
modifiedPage = _pagePool.Get(update.PageNumber);
var pageHead = pages.GetPageHead(update.PageNumber, CacheHints.ForUpdate);
using (var originalPage = pageHead.GetVersion(Root.Transaction.BeginVersionNumber))
originalPage.Data.CopyTo(modifiedPage.Data, 0);
SetModifiedPage(modifiedPage);
}
update.Data.CopyTo(modifiedPage.Data, update.Offset);
}
}
finally
{
modifiedPage.Dispose();
}
}
}
public PageCache(
IFileSet fileSet,
IDatabase database,
IPagePoolFactory pagePoolFactory,
IStartupLog startupLog,
IErrorLog errorLog)
{
_startupLog = startupLog;
_errorLog = errorLog;
_fileSet = fileSet;
_database = database;
startupLog.WriteLine("Creating a new page cache for " + _fileSet);
_pagePool = pagePoolFactory.Create(fileSet.PageSize);
_pages = new PageHeadCollection(fileSet, startupLog, errorLog, _pagePool);
_versions = new VersionHeadCollection(startupLog, errorLog, database);
_transactions = new TransactionHeadCollection(startupLog, errorLog, _pagePool);
}
public void Update(ITransaction transaction, IEnumerable <PageUpdate> updates, PageHeadCollection pages)
{
if (transaction == null)
{
IPage page = null;
foreach (var update in updates.OrderBy(u => u.PageNumber).ThenBy(u => u.SequenceNumber))
{
if (page == null || page.PageNumber != update.PageNumber)
{
if (page != null)
{
page.Dispose();
}
page = pages.GetPageHead(update.PageNumber, CacheHints.ForUpdate).GetVersion(null);
}
update.Data.CopyTo(page.Data, update.Offset);
}
if (page != null)
{
page.Dispose();
}
return;
}
TransactionHead transactionHead;
lock (_transactions)
if (!_transactions.TryGetValue(transaction.TransactionId, out transactionHead))
{
throw new FileLayerException("You can not apply updates to a transaction context before the transaction has begun or after it has ended");
}
transactionHead.AddUpdates(updates, pages);
}
public IPage GetPage(ITransaction transaction, ulong pageNumber, CacheHints hints, PageHeadCollection pages)
{
PageHead pageHead;
if (transaction == null)
{
pageHead = pages.GetPageHead(pageNumber, hints);
return(pageHead == null ? null : pageHead.GetVersion(null));
}
TransactionHead transactionHead;
lock (_transactions)
if (!_transactions.TryGetValue(transaction.TransactionId, out transactionHead))
{
throw new FileLayerException("You can not get pages for a transaction until you begin the transaction");
}
var modifiedPage = transactionHead.GetModifiedPage(pageNumber);
if (modifiedPage != null)
{
return(modifiedPage);
}
pageHead = pages.GetPageHead(pageNumber, hints);
return(pageHead == null ? null : pageHead.GetVersion(transactionHead.Root.Transaction.BeginVersionNumber));
}