public void Free(LowLevelTransaction tx, int scratchNumber, long page, long?txId)
{
var scratch = _scratchBuffers[scratchNumber];
scratch.File.Free(page, txId);
if (scratch.File.AllocatedPagesCount != 0)
{
return;
}
List <ScratchBufferFile> recycledScratchesToDispose = null;
while (_recycleArea.First != null)
{
var recycledScratch = _recycleArea.First.Value;
if (IsLowMemory() == false &&
DateTime.UtcNow - recycledScratch.RecycledAt <= RecycledScratchFileTimeout)
{
break;
}
_recycleArea.RemoveFirst();
if (recycledScratch.File.HasActivelyUsedBytes(_env.PossibleOldestReadTransaction(tx)))
{
// even though this was in the recycle area, there might still be some transactions looking at it
// so we cannot dispose it right now, the disposal will happen in RemoveInactiveScratches
// when we are sure it's really no longer in use
continue;
}
_scratchBuffers.TryRemove(recycledScratch.Number, out var _);
if (recycledScratchesToDispose == null)
{
recycledScratchesToDispose = new List <ScratchBufferFile>();
}
recycledScratchesToDispose.Add(recycledScratch.File);
}
if (recycledScratchesToDispose != null)
{
using (_env.IsInPreventNewTransactionsMode == false ? _env.PreventNewTransactions() : (IDisposable)null)
{
// we're about to dispose recycled scratch pagers, we need to update the cache so next transactions won't attempt to EnsurePagerStateReference() on them
UpdateCacheForPagerStatesOfAllScratches();
}
foreach (var recycledScratch in recycledScratchesToDispose)
{
recycledScratch.Dispose();
_scratchSpaceMonitor.Decrease(recycledScratch.NumberOfAllocatedPages * Constants.Storage.PageSize);
}
_forTestingPurposes?.ActionToCallDuringRemovalsOfRecycledScratchesRightAfterDisposingScratches?.Invoke();
}
if (scratch == _current)
{
if (scratch.File.Size <= _options.MaxScratchBufferSize)
{
// we'll take the chance that no one is using us to reset the memory allocations
// and avoid fragmentation, we can only do that if no transaction is looking at us
if (scratch.File.HasActivelyUsedBytes(_env.PossibleOldestReadTransaction(tx)) == false)
{
scratch.File.Reset();
}
return;
}
// this is the current one, but the size is too big, let us trim it
var newCurrent = NextFile(_options.InitialLogFileSize, _options.MaxScratchBufferSize);
newCurrent.File.PagerState.AddRef();
_current = newCurrent;
}
TryRecycleScratchFile(scratch);
}