private unsafe void TransactionMerger()
{
    var existing = new HashSet<long>();
    var tasks = new List<TaskCompletionSource<object>>();
    while (_cts.IsCancellationRequested == false)
    {
        existing.Clear();
        tasks.Clear();
        double value;
        using (var tx = _storageEnvironment.WriteTransaction())
        using (Slice.From(tx.Allocator, "dummy-val", out Slice dummy))
        using (Slice.External(tx.Allocator, (byte*)&value, sizeof(double), out Slice valueSlice))
        {
            var fst = tx.FixedTreeFor(dummy, valSize: sizeof(double));

            int count = 0;
            Entry entry;
            var propertiesInsertionBuffer = new BlittableJsonReaderObject.PropertiesInsertionBuffer();
            while (_entries.TryDequeue(out entry))
            {

                var keyHash = (long)entry.Key.DebugHash;

                using (Slice.External(tx.Allocator, (byte*)&keyHash, sizeof(long), out Slice slice))
                {
                    fst.RepurposeInstance(slice, clone: false);

                    value = entry.Value;
                    fst.Add(entry.Time.Ticks, valueSlice);
                }
                if (existing.Add(keyHash))
                {
                    int propCount = entry.Key.GetPropertiesByInsertionOrder(propertiesInsertionBuffer);
                    var prop = new BlittableJsonReaderObject.PropertyDetails();

                    for (int i = 0; i < propCount; i++)
                    {
                        entry.Key.GetPropertyByIndex(propertiesInsertionBuffer.Properties[i], ref prop);
                        var tree = tx.CreateTree(prop.Name);
                        var matches = tree.FixedTreeFor(prop.Value.ToString());
                        matches.Add(keyHash);
                    }
                }
                tasks.Add(entry.Tcs);
                if (count++ > 25_000)
                {
                    _hasEntries.Set();
                    break;
                }
            }
            tx.Commit();
        }
        foreach (var tcs in tasks)
        {
            tcs.TrySetResult(null);
        }
        _hasEntries.Wait();
        _hasEntries.Reset();
    }
}