public void TryRecovery()
{
var journal = JournalService.GetJournalFilename(_connectionString, false);
// no journal file, nothing to do
if (string.IsNullOrEmpty(journal))
{
return;
}
// if I can open journal file, test FINISH_POSITION
this.OpenExclusiveFile(journal, (stream) =>
{
// check if FINISH_POSITON is true
using (var reader = new BinaryReader(stream))
{
reader.Seek(JournalService.FINISH_POSITION);
// if file is finish, datafile needs to be recovery. if not,
// the failure ocurrs during write journal file but not finish - just discard it
if (reader.ReadBoolean() == true)
{
this.DoRecovery(reader);
}
}
// close stream for delete file
stream.Close();
File.Delete(journal);
});
// if I can't open, it's in use (and it's ok, there is a transaction executing in another process)
}
public void CreateJournalFile(Action action)
{
if (!_connectionString.JournalEnabled)
{
action();
return;
}
var journal = JournalService.GetJournalFilename(_connectionString, true);
// create journal file in EXCLUSIVE mode
using (var stream = File.Open(journal,
FileMode.Create, FileAccess.ReadWrite, FileShare.None))
{
using (var writer = new BinaryWriter(stream))
{
// first, allocate all journal file
var total = (uint)_cache.GetDirtyPages().Count();
stream.SetLength(total * BasePage.PAGE_SIZE);
uint index = 0;
// for better performance, write first page at end of file and others in sequence order
foreach (var page in _cache.GetDirtyPages())
{
if (index == 0)
{
this.WritePageInJournal(total - 1, writer, page);
}
else
{
this.WritePageInJournal(index, writer, page);
}
index++;
}
// flush all data
writer.Flush();
// mark header as finish
writer.Seek(FINISH_POSITION);
writer.Write(true); // mark as TRUE
// flush last finish mark
writer.Flush();
action();
}
stream.Dispose();
File.Delete(journal);
}
}
public void CreateJournalFile(Action action)
{
if (!_connectionString.JournalEnabled)
{
action();
return;
}
var journal = JournalService.GetJournalFilename(_connectionString, true);
// create journal file in EXCLUSIVE mode
using (var stream = new FileStream(journal,
FileMode.Create, FileAccess.ReadWrite, FileShare.None, BasePage.PAGE_SIZE))
{
using (var writer = new BinaryWriter(stream))
{
// first, allocate all journal file
var total = (uint)_cache.GetDirtyPages().Count();
stream.SetLength(total * BasePage.PAGE_SIZE);
// write all dirty pages in sequence on journal file
foreach (var page in _cache.GetDirtyPages())
{
this.WritePageInJournal(writer, page);
}
// flush all data
writer.Flush();
// mark header as finish
stream.Seek(FINISH_POSITION, SeekOrigin.Begin);
writer.Write(true); // mark as TRUE
// flush last finish mark
writer.Flush();
action();
}
stream.Dispose();
File.Delete(journal);
}
}
internal TransactionService(DiskService disk, CacheService cache, JournalService journal)
{
_disk = disk;
_cache = cache;
_journal = journal;
}
internal TransactionService(DiskService disk, CacheService cache, JournalService journal)
{
_disk = disk;
_cache = cache;
_journal = journal;
}
