//private const int ObjectBlockCountThreshold = 64;
/// <summary>
/// If in AutoFlush mode and data Value is not saved in Key segment,
/// this method will Add/Update Big Data Value to disk and at end of the process,
/// set the Value to null to conserve memory.
/// </summary>
/// <param name="item"></param>
/// <returns></returns>
private bool SetBigDataValue(BTreeItemOnDisk item)
{
if (!IsDataInKeySegment)
{
// load meta data so Blocks layout in-memory can get recreated...
long da = GetId(item.Value.DiskBuffer);
if (da >= 0)
{
if (!item.Value.DiskBuffer.IsFolded)
{
if (item.Value.DiskBuffer.IsFoldedInfoOnDisk)
{
// read the block chain info so these blocks will not be replaced during update!
var metaBlocks = DataBlockDriver.ReadBlockInfoFromDisk(this, da);
// assign read block chain info to a DataBlock simulating a "Folded" scenario.
item.Value.diskBuffer.foldedDataAddresses = metaBlocks.ToArray();
item.Value.diskBuffer.contiguousBlockCount = metaBlocks[0].BlockCount;
}
}
// delete the blocks on disk if they are big and data being set is null
if (item.Value.Data == null &&
item.Value.DiskBuffer.IsFolded &&
item.Value.DiskBuffer.CountMembers() >= 1024)
{
DataSet.DataBlockDriver.Remove(DataSet, item.Value.DiskBuffer);
item.Value.DiskBuffer = CreateBlock();
}
}
// save big data to disk
if (item.Value.diskBuffer != null)
{
item.Value.diskBuffer.Unfold(this);
}
Sop.DataBlock b = WriteToBlock(item.Value);
DataSet.DataBlockDriver.SetDiskBlock(DataSet, b, false, false);
var cnt = b.ProcessHeadSets();
// store blocks to the pool if block count < 500, otherwise direct write to disk!
if (cnt < File.Profile.BigDataBlockCount)
{
AddToBlocks(b, Blocks);
item.ValueLoaded = true;
item.Value.IsDirty = false;
item.IsDirty = false;
item.Value.diskBuffer.Fold();
}
else
{
if (cnt <= 500)
{
AddToBlocks(b, Blocks);
}
else
{
// direct write to disk
var blocks = new Collections.Generic.SortedDictionary <long, Sop.DataBlock>();
AddToBlocks(b, blocks);
WriteBlocksToDisk(DataSet, blocks, false);
}
item.IsDirty = false;
item.Value.IsDirty = false;
item.ValueLoaded = false;
item.Value.diskBuffer.Fold();
// nullify big data to conserve memory
item.Value.Data = null;
}
return(true);
}
return(false);
}
