/// <summary>
/// Reclaim unused space (Directly on the table, stopping the defragmentation can result in permanent corruption)
/// </summary>
/// <returns>The number of bytes saved</returns>
public async ValueTask <int> UnsafeDefragment(CancellationToken cancellationToken = default)
{
ClearTrie();
await ClearFileStream();
int saved = 0;
var fileName = await tx.Schema.GetFileNameOrCreate(tableName);
if (!await tx._Engine.Storages.Exists(fileName.ToString()))
{
return(0);
}
await using var fs = await tx._Engine.Storages.OpenStorage(fileName.ToString());
await using var cache = new CacheStorage(fs, false, PagePool, true);
var trie = await LTrie.OpenFromStorage(cache);
saved = await trie.Defragment(cancellationToken);
await cache.Flush();
await fs.Flush();
return(saved);
}
/// <summary>
/// Reclaim unused space (Copy the table in a temporary file, defragment and replace the original table)
/// </summary>
/// <returns>The number of bytes saved</returns>
public async ValueTask <int> Defragment(CancellationToken cancellationToken = default)
{
ClearTrie();
await ClearFileStream();
// We copy the current table on a temporary file, then defragment that
// once defragmentation is complete, we copy the temp file to the current table
// this prevent corruption if anything happen on the middle of the defragmentation
var fileName = await tx.Schema.GetFileNameOrCreate(tableName);
var tmpFile = $"{fileName}_tmp";
if (!await tx._Engine.Storages.Exists(fileName.ToString()))
{
return(0);
}
await tx._Engine.Storages.Copy(fileName.ToString(), tmpFile);
int saved = 0;
try
{
await using var fs = await tx._Engine.Storages.OpenStorage(tmpFile);
await using var cache = new CacheStorage(fs, false, PagePool, true);
var trie = await LTrie.OpenFromStorage(cache);
saved = await trie.Defragment(cancellationToken);
await cache.Flush();
await fs.Flush();
}
catch
{
await tx._Engine.Storages.Delete(tmpFile);
throw;
}
await tx._Engine.Storages.Move(tmpFile, fileName.ToString());
return(saved);
}
