Iterate through all undeleted Documents in a Lucene (.Net) index

Question

I want to get the count of all un-deleted documents of a Lucene (.Net 2.4) index and then read my stored fields of all or a range of these docs. After reading the Lucene help I'm not quite sure, whether IndexReader.NumDocs() returns the count of all docs or only the undeleted ones. Can I simply iterate through IndexReader.Document[] and or does it contain deleted Documents?

If NumDocs() and Docmuent[] does contain both deleted und undeleted docs I suppose I'll have to do something like this:

int totalCount = reader.NumDocs();
int totalCountUndeleted = totalCount;
for (int iDoc = 0; iDoc < totalCount; iDoc++)
  if (reader.IsDeleted(iDoc))
    totalCountUndeleted--;

for (int iDoc = 0; iDoc < totalCount; iDoc++)
{
  if (!reader.IsDeleted(iDoc))
  {
     Document doc = reader.Document(iDoc);
     // read fields
  }
}

Is this the right way or is there any other possible way? Thanks

I found reader.NumDeletedDocs(). So getting totalCount is easier: int totalCount = reader.NumDocs() - reader.NumDeletedDocs(); — gumo

Shashikant Kore Shashikant Kore · Accepted Answer · 2010-12-02T15:24:03

IndexReader.NumDocs will give you number of active documents. IndexReader.MaxDoc is the number one greater than maximum document number in the index. Following code will read all the active documents in the index.

int max = reader.MaxDoc();
for (int iDoc = 0; iDoc < max; iDoc++)
{
  if (!reader.IsDeleted(iDoc))
  {
     Document doc = reader.Document(iDoc);
     // read fields
  }
}

Iterate through all undeleted Documents in a Lucene (.Net) index

2 Answers