/// <summary>Checks if a list of reads conflicts with at least one write performed in this transaction window</summary>
/// <param name="reads">List of reads to check for conflicts</param>
/// <param name="version">Sequence number of the transaction that performed the reads</param>
/// <returns>True if at least one read is conflicting with a write with a higher sequence number; otherwise, false.</returns>
public bool Conflicts(ColaRangeSet <Slice> reads, ulong version)
{
Contract.Requires(reads != null);
//Debug.WriteLine("* Testing for conflicts for: " + String.Join(", ", reads));
if (version > m_maxVersion)
{ // all the writes are before the reads, so no possible conflict!
//Debug.WriteLine(" > cannot conflict");
return(false);
}
using (var scratch = new UnmanagedSliceBuilder())
{
//TODO: do a single-pass version of intersection checking !
foreach (var read in reads)
{
scratch.Clear();
scratch.Append(read.Begin);
var p = scratch.Count;
scratch.Append(read.End);
var begin = scratch.ToUSlice(p);
var end = scratch.ToUSlice(p, scratch.Count - p);
if (m_writeConflicts.Intersect(begin, end, version, (v, min) => v > min))
{
Debug.WriteLine(" > Conflicting read: " + read);
return(true);
}
}
}
//Debug.WriteLine(" > No conflicts found");
return(false);
}
public void MergeWrites(ColaRangeSet <Slice> writes, ulong version)
{
Contract.Requires(!m_closed && writes != null && version >= m_minVersion && (!m_closed || version <= m_maxVersion));
if (m_disposed)
{
ThrowDisposed();
}
if (m_closed)
{
throw new InvalidOperationException("This transaction has already been closed");
}
//Debug.WriteLine("* Merging writes conflicts for version " + version + ": " + String.Join(", ", writes));
foreach (var range in writes)
{
var begin = range.Begin;
var end = range.End;
USlice beginKey, endKey;
if (begin.Offset == end.Offset && object.ReferenceEquals(begin.Array, end.Array) && end.Count >= begin.Count)
{ // overlapping keys
endKey = Store(end);
beginKey = endKey.Substring(0, (uint)begin.Count);
}
else
{
beginKey = Store(begin);
endKey = Store(end);
}
m_writeConflicts.Mark(beginKey, endKey, version);
}
++m_commitCount;
if (version > m_maxVersion)
{
m_maxVersion = version;
}
}