/// <summary>
/// Write a block and return the offset after the block
/// </summary>
/// <param name="block"></param>
/// <param name="offset"></param>
/// <returns></returns>
private long WriteBlock(PersistentBlock block, long offset)
{
StorageStream.Seek(offset, SeekOrigin.Begin);
var writer = new BinaryWriter(StorageStream);
block.Write(writer);
writer.Flush();
return(StorageStream.Position);
}
/// <summary>
/// Remove dirty blocks thus compacting the storage
/// </summary>
public void CleanStorage()
{
if (File.Exists(TempFileName))
{
File.Delete(TempFileName);
}
var fullPath = Path.Combine(DataPath, StorageFileName);
var tempPath = Path.Combine(DataPath, TempFileName);
using (var tempStream = new FileStream(tempPath, FileMode.Create))
{
var writer = new BinaryWriter(tempStream);
StorageStream.Dispose();
StorageStream = new FileStream(fullPath, FileMode.OpenOrCreate);
var reader = new BinaryReader(StorageStream);
var block = new PersistentBlock();
long offset = 0;
// read all the blocks
while (block.Read(reader))
{
if (block.BlockStatus == BlockStatus.Active)
{
offset = (int)StorageStream.Position;
block.Write(writer);
}
}
StorageSize = offset;
writer.Flush();
StorageStream.Dispose();
}
File.Delete(fullPath);
File.Move(tempPath, fullPath);
StorageStream = new FileStream(fullPath, FileMode.OpenOrCreate);
InactiveBlockCount = 0;
}
/// <summary>
/// For recovery tests only
/// </summary>
/// <param name="primaryKey"></param>
public void MakeCorruptedBlock(string primaryKey)
{
if (BlockInfoByPrimaryKey.TryGetValue(primaryKey, out var info))
{
var block = new PersistentBlock();
StorageStream.Seek(info.Offset, SeekOrigin.Begin);
var reader = new BinaryReader(StorageStream);
block.Read(reader);
block.Hash = block.Hash + 1; // the hash will not match so the block is corrupted
StorageStream.Seek(info.Offset, SeekOrigin.Begin);
var writer = new BinaryWriter(StorageStream);
block.Write(writer);
}
}
public void DeleteBlock(string primaryKey, int transactionId)
{
if (BlockInfoByPrimaryKey.TryGetValue(primaryKey, out var blockInfo))
{
StorageStream.Seek(blockInfo.Offset, SeekOrigin.Begin);
var reader = new BinaryReader(StorageStream);
var block = new PersistentBlock();
block.Read(reader);
if (block.BlockStatus != BlockStatus.Active)
{
// if the same id ok. We are re executing a transaction that was not marked as Processed.
// It happens if the server crashes during the update of persistence blocks. The transaction is simply played
// again when the server is restarted
if (block.LastTransactionId != transactionId)
{
throw new NotSupportedException(
$"Trying to delete an inactive block for primary key {primaryKey}");
}
}
block.BlockStatus = BlockStatus.Deleted;
block.LastTransactionId = transactionId;
StorageStream.Seek(blockInfo.Offset, SeekOrigin.Begin);
var writer = new BinaryWriter(StorageStream);
block.Write(writer);
writer.Flush();
BlockInfoByPrimaryKey.Remove(primaryKey);
InactiveBlockCount++;
_backupStorage?.DeleteBlock(primaryKey, transactionId);
}
else
{
throw new NotSupportedException($"Active block not found for primary key {primaryKey}");
}
}
