public async Task <List <Document> > ReadDocsAfter(long docId)
{
var batches = new List <List <Document> >();
_file.Position = _file.Length;
try
{
while (_file.Position > 0)
{
var batch = await DocumentSerializer.DeserializeBatchFromRightToLeft(_file);
batches.Add(batch);
if (batch.First().Id <= docId)
{
break;
}
}
var result = new List <Document>();
foreach (var doc in batches.SelectMany(x => x))
{
if (doc.Id > docId)
{
result.Add(doc);
}
}
return(result);
}
finally
{
_file.Position = _file.Length;
}
}
private async Task TruncateByDocId(long docId)
{
using (Measured.Operation("wal_truncate"))
{
_file.Position = _file.Length;
while (_file.Position != 0)
{
var batch = await DocumentSerializer.DeserializeBatchFromRightToLeft(_file);
var firstDocIdInBatch = batch[0].Id;
if (docId >= firstDocIdInBatch)
{
await TruncateByFileOffset(_file.Position);
break;
}
}
}
}
private async Task <DocIdGenerator> CreateDocIdGenerator()
{
if (_file.Length == 0)
{
return(new DocIdGenerator(0));
}
var initialPos = _file.Position;
try
{
var lastBatch = await DocumentSerializer.DeserializeBatchFromRightToLeft(_file);
var lastDoc = lastBatch[lastBatch.Count - 1];
return(new DocIdGenerator(lastDoc.Id));
}
finally
{
_file.Position = initialPos;
}
}
