public void Can_collect_exact_phrase_joined_by_and()
{
var dir = Path.Combine(Setup.Dir, "Can_collect_exact_phrase_joined_by_and");
if (!Directory.Exists(dir))
{
Directory.CreateDirectory(dir);
}
var docs = new List <Dictionary <string, string> >
{
new Dictionary <string, string> {
{ "_id", "0" }, { "title", "rambo first blood" }
},
new Dictionary <string, string> {
{ "_id", "1" }, { "title", "rambo 2" }
},
new Dictionary <string, string> {
{ "_id", "2" }, { "title", "rocky 2" }
},
new Dictionary <string, string> {
{ "_id", "3" }, { "title", "the raiders of the lost ark" }
},
new Dictionary <string, string> {
{ "_id", "4" }, { "title", "the rain man" }
},
new Dictionary <string, string> {
{ "_id", "5" }, { "title", "the good, the bad and the ugly" }
}
};
string indexName;
using (var writer = new StreamWriteOperation(dir, new Analyzer(), docs.ToStream()))
{
indexName = writer.Execute();
}
var query = new QueryParser(new Analyzer()).Parse("+title:the");
using (var collector = new Collector(dir, IxInfo.Load(Path.Combine(dir, indexName + ".ix")), new Tfidf()))
{
var scores = collector.Collect(query).ToList();
Assert.That(scores.Count, Is.EqualTo(3));
Assert.IsTrue(scores.Any(d => d.DocumentId == 3));
Assert.IsTrue(scores.Any(d => d.DocumentId == 4));
Assert.IsTrue(scores.Any(d => d.DocumentId == 5));
}
query = new QueryParser(new Analyzer()).Parse("+title:the +title:ugly");
using (var collector = new Collector(dir, IxInfo.Load(Path.Combine(dir, indexName + ".ix")), new Tfidf()))
{
var scores = collector.Collect(query).ToList();
Assert.That(scores.Count, Is.EqualTo(1));
Assert.IsTrue(scores.Any(d => d.DocumentId == 5));
}
}
public void Can_collect_prefixed()
{
var dir = CreateDir();
var docs = new List <dynamic>
{
new { _id = "0", title = "rambo" },
new { _id = "1", title = "rambo 2" },
new { _id = "2", title = "rocky 2" },
new { _id = "3", title = "raiders of the lost ark" },
new { _id = "4", title = "rain man" }
}.ToDocuments(primaryKeyFieldName: "_id");
var writer = new UpsertTransaction(dir, new Analyzer(), compression: Compression.Lz, documents: docs);
long indexName = writer.Write();
writer.Dispose();
using (var collector = new Collector(dir, IxInfo.Load(Path.Combine(dir, indexName + ".ix")), new Tfidf()))
{
var scores = collector.Collect(new QueryContext("title", "ra")
{
Prefix = true
}).ToList();
Assert.AreEqual(4, scores.Count);
Assert.IsTrue(scores.Any(d => d.DocumentId == 0));
Assert.IsTrue(scores.Any(d => d.DocumentId == 1));
Assert.IsTrue(scores.Any(d => d.DocumentId == 3));
Assert.IsTrue(scores.Any(d => d.DocumentId == 4));
}
}
public void Can_collect_prefixed()
{
var dir = Path.Combine(Dir, "Can_collect_prefixed");
if (!Directory.Exists(dir))
{
Directory.CreateDirectory(dir);
}
var docs = new List <Field>
{
new Field(0, "_id", "0"), new Field(0, "title", "rambo"),
new Field(1, "_id", "1"), new Field(1, "title", "rambo 2"),
new Field(2, "_id", "2"), new Field(2, "title", "rocky 2"),
new Field(3, "_id", "3"), new Field(3, "title", "raiders of the lost ark"),
new Field(4, "_id", "4"), new Field(4, "title", "rain man")
}.GroupBy(f => f.DocumentId).Select(g => new Document(g.Key, g.ToList()));
var writer = new DocumentUpsertOperation(dir, new Analyzer(), compression: Compression.Lz, primaryKey: "_id", documents: docs);
long indexName = writer.Commit();
using (var collector = new Collector(dir, IxInfo.Load(Path.Combine(dir, indexName + ".ix")), new Tfidf()))
{
var scores = collector.Collect(new QueryContext("title", "ra")
{
Prefix = true
}).ToList();
Assert.AreEqual(4, scores.Count);
Assert.IsTrue(scores.Any(d => d.DocumentId == 0));
Assert.IsTrue(scores.Any(d => d.DocumentId == 1));
Assert.IsTrue(scores.Any(d => d.DocumentId == 3));
Assert.IsTrue(scores.Any(d => d.DocumentId == 4));
}
}
public DocumentScore(int documentId, UInt64 docHash, double score, IxInfo ix)
{
DocumentId = documentId;
Score = score;
Ix = ix;
DocHash = docHash;
}
public void Can_collect_near()
{
var dir = Path.Combine(Setup.Dir, "Can_collect_near");
if (!Directory.Exists(dir))
{
Directory.CreateDirectory(dir);
}
var docs = new List <Dictionary <string, string> >
{
new Dictionary <string, string> {
{ "_id", "0" }, { "title", "rambo" }
},
new Dictionary <string, string> {
{ "_id", "1" }, { "title", "rambo 2" }
},
new Dictionary <string, string> {
{ "_id", "2" }, { "title", "rocky 2" }
},
new Dictionary <string, string> {
{ "_id", "3" }, { "title", "raiders of the lost ark" }
},
new Dictionary <string, string> {
{ "_id", "4" }, { "title", "tomb raider" }
}
};
string indexName;
using (var writer = new StreamWriteOperation(dir, new Analyzer(), docs.ToStream()))
{
indexName = writer.Execute();
}
using (var collector = new Collector(dir, IxInfo.Load(Path.Combine(dir, indexName + ".ix")), new Tfidf()))
{
var scores = collector.Collect(new QueryContext("title", "raider")
{
Fuzzy = false, Edits = 1
}).ToList();
Assert.That(scores.Count, Is.EqualTo(1));
Assert.IsTrue(scores.Any(d => d.DocumentId == 4));
}
using (var collector = new Collector(dir, IxInfo.Load(Path.Combine(dir, indexName + ".ix")), new Tfidf()))
{
var scores = collector.Collect(new QueryContext("title", "raider")
{
Fuzzy = true, Edits = 1
}).ToList();
Assert.That(scores.Count, Is.EqualTo(2));
Assert.IsTrue(scores.Any(d => d.DocumentId == 3));
Assert.IsTrue(scores.Any(d => d.DocumentId == 4));
}
}
public void Can_collect_exact_phrase_joined_by_not()
{
var dir = Path.Combine(Dir, "Can_collect_exact_phrase_joined_by_not");
if (!Directory.Exists(dir))
{
Directory.CreateDirectory(dir);
}
var docs = new List <List <Field> >
{
new List <Field> {
new Field("_id", "0"), new Field("title", "rambo first blood")
},
new List <Field> {
new Field("_id", "1"), new Field("title", "rambo 2")
},
new List <Field> {
new Field("_id", "2"), new Field("title", "rocky 2")
},
new List <Field> {
new Field("_id", "3"), new Field("title", "raiders of the lost ark")
},
new List <Field> {
new Field("_id", "4"), new Field("title", "the rain man")
},
new List <Field> {
new Field("_id", "5"), new Field("title", "the good, the bad and the ugly")
}
};
var writer = new DocumentUpsertOperation(dir, new Analyzer(), compression: Compression.QuickLz, primaryKey: "_id", documents: docs);
long indexName = writer.Commit();
var query = new QueryParser(new Analyzer()).Parse("+title:the");
using (var collector = new Collector(dir, IxInfo.Load(Path.Combine(dir, indexName + ".ix")), new Tfidf()))
{
var scores = collector.Collect(query).ToList();
Assert.AreEqual(3, scores.Count);
Assert.IsTrue(scores.Any(d => d.DocumentId == 3));
Assert.IsTrue(scores.Any(d => d.DocumentId == 4));
Assert.IsTrue(scores.Any(d => d.DocumentId == 5));
}
query = new QueryParser(new Analyzer()).Parse("+title:the -title:ugly");
using (var collector = new Collector(dir, IxInfo.Load(Path.Combine(dir, indexName + ".ix")), new Tfidf()))
{
var scores = collector.Collect(query).ToList();
Assert.AreEqual(2, scores.Count);
Assert.IsTrue(scores.Any(d => d.DocumentId == 3));
Assert.IsTrue(scores.Any(d => d.DocumentId == 4));
}
}
public void Can_collect_exact_phrase_joined_by_or()
{
var dir = Path.Combine(CreateDir(), "Can_collect_exact_phrase_joined_by_or");
if (!Directory.Exists(dir))
{
Directory.CreateDirectory(dir);
}
var docs = new List <dynamic>
{
new { _id = "0", title = "rambo first blood" },
new { _id = "1", title = "rambo 2" },
new { _id = "2", title = "rocky 2" },
new { _id = "3", title = "raiders of the lost ark" },
new { _id = "4", title = "the rain man" },
new { _id = "5", title = "the good, the bad and the ugly" }
}.ToDocuments();
var writer = new DocumentsUpsertOperation(dir, new Analyzer(), compression: Compression.Lz, primaryKey: "_id", documents: docs);
long indexName = writer.Commit();
var query = new QueryParser(new Analyzer()).Parse("+title:rocky");
using (var collector = new Collector(dir, IxInfo.Load(Path.Combine(dir, indexName + ".ix")), new Tfidf()))
{
var scores = collector.Collect(query).ToList();
Assert.AreEqual(1, scores.Count);
Assert.IsTrue(scores.Any(d => d.DocumentId == 2));
}
query = new QueryParser(new Analyzer()).Parse("+title:rambo");
using (var collector = new Collector(dir, IxInfo.Load(Path.Combine(dir, indexName + ".ix")), new Tfidf()))
{
var scores = collector.Collect(query).ToList();
Assert.AreEqual(2, scores.Count);
Assert.IsTrue(scores.Any(d => d.DocumentId == 0));
Assert.IsTrue(scores.Any(d => d.DocumentId == 1));
}
query = new QueryParser(new Analyzer()).Parse("+title:rocky title:rambo");
using (var collector = new Collector(dir, IxInfo.Load(Path.Combine(dir, indexName + ".ix")), new Tfidf()))
{
var scores = collector.Collect(query).ToList();
Assert.AreEqual(3, scores.Count);
Assert.IsTrue(scores.Any(d => d.DocumentId == 0));
Assert.IsTrue(scores.Any(d => d.DocumentId == 1));
Assert.IsTrue(scores.Any(d => d.DocumentId == 2));
}
}
public void Can_collect_near()
{
var dir = Path.Combine(Dir, "Can_collect_near");
if (!Directory.Exists(dir))
{
Directory.CreateDirectory(dir);
}
var docs = new List <List <Field> >
{
new List <Field> {
new Field("_id", "0"), new Field("title", "rambo")
},
new List <Field> {
new Field("_id", "1"), new Field("title", "rambo 2")
},
new List <Field> {
new Field("_id", "2"), new Field("title", "rocky 2")
},
new List <Field> {
new Field("_id", "3"), new Field("title", "raiders of the lost ark")
},
new List <Field> {
new Field("_id", "4"), new Field("title", "tomb raider")
}
};
var writer = new DocumentUpsertOperation(dir, new Analyzer(), compression: Compression.QuickLz, primaryKey: "_id", documents: docs);
long indexName = writer.Commit();
using (var collector = new Collector(dir, IxInfo.Load(Path.Combine(dir, indexName + ".ix")), new Tfidf()))
{
var scores = collector.Collect(new QueryContext("title", "raider")
{
Fuzzy = false, Edits = 1
}).ToList();
Assert.AreEqual(1, scores.Count);
Assert.IsTrue(scores.Any(d => d.DocumentId == 4));
}
using (var collector = new Collector(dir, IxInfo.Load(Path.Combine(dir, indexName + ".ix")), new Tfidf()))
{
var scores = collector.Collect(new QueryContext("title", "raider")
{
Fuzzy = true, Edits = 1
}).ToList();
Assert.AreEqual(2, scores.Count);
Assert.IsTrue(scores.Any(d => d.DocumentId == 3));
Assert.IsTrue(scores.Any(d => d.DocumentId == 4));
}
}
public void Can_rank_near_term()
{
var dir = Path.Combine(Setup.Dir, "Can_rank_near_term");
if (!Directory.Exists(dir))
{
Directory.CreateDirectory(dir);
}
var docs = new List <Dictionary <string, string> >
{
new Dictionary <string, string> {
{ "_id", "0" }, { "title", "Gustav Horn, Count of Pori" }
},
new Dictionary <string, string> {
{ "_id", "1" }, { "title", "Port au Port Peninsula" }
},
new Dictionary <string, string> {
{ "_id", "2" }, { "title", "Pore" }
},
new Dictionary <string, string> {
{ "_id", "3" }, { "title", "Born 2.0" }
},
new Dictionary <string, string> {
{ "_id", "4" }, { "title", "P**n" }
}
};
string indexName;
using (var writer = new StreamWriteOperation(dir, new Analyzer(), docs.ToStream()))
{
indexName = writer.Execute();
}
var query = new QueryParser(new Analyzer()).Parse("+title:p**n~");
using (var collector = new Collector(dir, IxInfo.Load(Path.Combine(dir, indexName + ".ix")), new Tfidf()))
{
var scores = collector.Collect(query).ToList();
Assert.That(scores.Count, Is.EqualTo(5));
Assert.IsTrue(scores.First().DocumentId.Equals(4));
Assert.IsTrue(scores[1].DocumentId.Equals(0));
Assert.IsTrue(scores[2].DocumentId.Equals(1));
Assert.IsTrue(scores[3].DocumentId.Equals(3));
Assert.IsTrue(scores[4].DocumentId.Equals(2));
}
}
public void Can_rank_near_phrase()
{
var dir = Path.Combine(Setup.Dir, "Can_rank_near_phrase");
if (!Directory.Exists(dir))
{
Directory.CreateDirectory(dir);
}
var docs = new List <Dictionary <string, string> >
{
new Dictionary <string, string> {
{ "_id", "0" }, { "title", "Tage Mage" }
},
new Dictionary <string, string> {
{ "_id", "1" }, { "title", "aye-aye" }
},
new Dictionary <string, string> {
{ "_id", "2" }, { "title", "Cage Rage Championships" }
},
new Dictionary <string, string> {
{ "_id", "3" }, { "title", "Page Up and Page Down keys" }
},
new Dictionary <string, string> {
{ "_id", "4" }, { "title", "Golden Age of P**n" }
}
};
string indexName;
using (var writer = new StreamWriteOperation(dir, new Analyzer(), docs.ToStream()))
{
indexName = writer.Execute();
}
var query = new QueryParser(new Analyzer()).Parse("+title:age of p**n~");
using (var collector = new Collector(dir, IxInfo.Load(Path.Combine(dir, indexName + ".ix")), new Tfidf()))
{
var scores = collector.Collect(query).ToList();
Assert.That(scores.Count, Is.EqualTo(5));
Assert.IsTrue(scores.First().DocumentId.Equals(4));
}
}
static void Export(string[] args)
{
var take = int.MaxValue;
var skip = 0;
if (Array.IndexOf(args, "--take") > 0)
{
take = int.Parse(args[Array.IndexOf(args, "--take") + 1]);
}
if (Array.IndexOf(args, "--skip") > 0)
{
skip = int.Parse(args[Array.IndexOf(args, "--skip") + 1]);
}
var sourceFileName = args[Array.IndexOf(args, "--source-file") + 1];
var targetFileName = args[Array.IndexOf(args, "--target-file") + 1];
var dir = Path.GetDirectoryName(sourceFileName);
var version = Path.GetFileNameWithoutExtension(sourceFileName);
var ix = IxInfo.Load(Path.Combine(dir, version + ".ix"));
Console.WriteLine("migrating...");
var writeTimer = new Stopwatch();
writeTimer.Start();
using (var outStream = new FileStream(targetFileName, FileMode.Create))
using (var jsonWriter = new StreamWriter(outStream, Encoding.UTF8))
using (var documents = new RDocStream(sourceFileName, ix.PrimaryKeyFieldName, skip, take))
{
jsonWriter.WriteLine("[");
foreach (var document in documents.ReadSource())
{
var dic = document.Fields.ToDictionary(x => x.Key, y => y.Value.Value);
var json = JsonConvert.SerializeObject(dic, Formatting.None);
jsonWriter.WriteLine(json);
}
jsonWriter.Write("]");
}
Console.WriteLine("write operation took {0}", writeTimer.Elapsed);
}
public void Can_collect_exact_phrase_joined_by_not()
{
var dir = CreateDir();
var docs = new List <dynamic>
{
new { _id = "0", title = "rambo first blood" },
new { _id = "1", title = "rambo 2" },
new { _id = "2", title = "rocky 2" },
new { _id = "3", title = "raiders of the lost ark" },
new { _id = "4", title = "the rain man" },
new { _id = "5", title = "the good, the bad and the ugly" }
}.ToDocuments(primaryKeyFieldName: "_id");
var writer = new UpsertTransaction(dir, new Analyzer(), compression: Compression.Lz, documents: docs);
long indexName = writer.Write();
writer.Dispose();
var query = new QueryParser(new Analyzer()).Parse("+title:the");
using (var collector = new Collector(dir, IxInfo.Load(Path.Combine(dir, indexName + ".ix")), new Tfidf()))
{
var scores = collector.Collect(query).ToList();
Assert.AreEqual(3, scores.Count);
Assert.IsTrue(scores.Any(d => d.DocumentId == 3));
Assert.IsTrue(scores.Any(d => d.DocumentId == 4));
Assert.IsTrue(scores.Any(d => d.DocumentId == 5));
}
query = new QueryParser(new Analyzer()).Parse("+title:the -title:ugly");
using (var collector = new Collector(dir, IxInfo.Load(Path.Combine(dir, indexName + ".ix")), new Tfidf()))
{
var scores = collector.Collect(query).ToList();
Assert.AreEqual(2, scores.Count);
Assert.IsTrue(scores.Any(d => d.DocumentId == 3));
Assert.IsTrue(scores.Any(d => d.DocumentId == 4));
}
}
public void Can_collect_near_phrase()
{
var dir = Path.Combine(Dir, "Can_collect_near_phrase_joined_by_and");
if (!Directory.Exists(dir))
{
Directory.CreateDirectory(dir);
}
var docs = new List <Field>
{
new Field(0, "_id", "0"), new Field(0, "title", "rambo first blood"),
new Field(1, "_id", "1"), new Field(1, "title", "rambo 2"),
new Field(2, "_id", "2"), new Field(2, "title", "rocky 2"),
new Field(3, "_id", "3"), new Field(3, "title", "the raid"),
new Field(4, "_id", "4"), new Field(4, "title", "the rain man"),
new Field(5, "_id", "5"), new Field(5, "title", "the good, the bad and the ugly")
}.GroupBy(f => f.DocumentId).Select(g => new Document(g.Key, g.ToList()));
var writer = new DocumentUpsertOperation(dir, new Analyzer(), compression: Compression.Lz, primaryKey: "_id", documents: docs);
long indexName = writer.Commit();
var query = new QueryParser(new Analyzer()).Parse("+title:rain man");
using (var collector = new Collector(dir, IxInfo.Load(Path.Combine(dir, indexName + ".ix")), new Tfidf()))
{
var scores = collector.Collect(query).ToList();
Assert.AreEqual(1, scores.Count);
Assert.IsTrue(scores.Any(d => d.DocumentId == 4));
}
query = new QueryParser(new Analyzer(), 0.75f).Parse("+title:rain man~");
using (var collector = new Collector(dir, IxInfo.Load(Path.Combine(dir, indexName + ".ix")), new Tfidf()))
{
var scores = collector.Collect(query).ToList();
Assert.AreEqual(1, scores.Count);
Assert.IsTrue(scores.Any(d => d.DocumentId == 4));
}
}
public void Can_delete()
{
var dir = CreateDir();
var docs = new List <dynamic>
{
new { _id = "0", title = "rambo first blood" },
new { _id = "1", title = "rambo 2" },
new { _id = "2", title = "rocky 2" },
new { _id = "3", title = "raiders of the lost ark" },
new { _id = "4", title = "the rain man" },
new { _id = "5", title = "the good, the bad and the ugly" }
}.ToDocuments(primaryKeyFieldName: "_id");
var writer = new UpsertTransaction(dir, new Analyzer(), compression: Compression.Lz, documents: docs);
long indexName = writer.Write();
writer.Dispose();
using (var collector = new Collector(dir, IxInfo.Load(Path.Combine(dir, indexName + ".ix")), new Tfidf()))
{
var scores = collector.Collect(new QueryContext("title", "rambo")).ToList();
Assert.AreEqual(2, scores.Count);
Assert.IsTrue(scores.Any(d => d.DocumentId == 0));
Assert.IsTrue(scores.Any(d => d.DocumentId == 1));
}
var operation = new DeleteByPrimaryKeyTransaction(dir, new[] { "0" });
operation.Commit();
using (var collector = new Collector(dir, IxInfo.Load(Path.Combine(dir, indexName + ".ix")), new Tfidf()))
{
var scores = collector.Collect(new QueryContext("title", "rambo")).ToList();
Assert.AreEqual(1, scores.Count);
Assert.IsTrue(scores.Any(d => d.DocumentId == 1));
}
}
public void Can_collect_by_id()
{
var dir = Path.Combine(CreateDir(), "Can_collect_by_id");
if (!Directory.Exists(dir))
{
Directory.CreateDirectory(dir);
}
var docs = new List <dynamic>
{
new { _id = "abc0123", title = "rambo first blood" },
new { _id = "1", title = "rambo 2" },
new { _id = "2", title = "rocky 2" },
new { _id = "3", title = "the raiders of the lost ark" },
new { _id = "four", title = "the rain man" },
new { _id = "5five", title = "the good, the bad and the ugly" }
}.ToDocuments();
var writer = new DocumentsUpsertOperation(dir, new Analyzer(), compression: Compression.Lz, primaryKey: "_id", documents: docs);
long indexName = writer.Commit();
using (var collector = new Collector(dir, IxInfo.Load(Path.Combine(dir, indexName + ".ix")), new Tfidf()))
{
var scores = collector.Collect(new QueryContext("_id", "3")).ToList();
Assert.AreEqual(1, scores.Count);
Assert.IsTrue(scores.Any(d => d.DocumentId == 3));
}
using (var collector = new Collector(dir, IxInfo.Load(Path.Combine(dir, indexName + ".ix")), new Tfidf()))
{
var scores = collector.Collect(new QueryContext("_id", "5five")).ToList();
Assert.AreEqual(1, scores.Count);
Assert.IsTrue(scores.Any(d => d.DocumentId == 5));
}
}
public void Can_collect_by_id()
{
var dir = Path.Combine(Dir, "Can_collect_by_id");
if (!Directory.Exists(dir))
{
Directory.CreateDirectory(dir);
}
var docs = new List <Field>
{
new Field(0, "_id", "abc0123"), new Field(0, "title", "rambo first blood"),
new Field(1, "_id", "1"), new Field(1, "title", "rambo 2"),
new Field(2, "_id", "2"), new Field(2, "title", "rocky 2"),
new Field(3, "_id", "3"), new Field(3, "title", "the raiders of the lost ark"),
new Field(4, "_id", "four"), new Field(4, "title", "the rain man"),
new Field(5, "_id", "5five"), new Field(5, "title", "the good, the bad and the ugly")
}.GroupBy(f => f.DocumentId).Select(g => new Document(g.Key, g.ToList())).OrderBy(d => d.Id);
var writer = new DocumentUpsertOperation(dir, new Analyzer(), compression: Compression.Lz, primaryKey: "_id", documents: docs);
long indexName = writer.Commit();
using (var collector = new Collector(dir, IxInfo.Load(Path.Combine(dir, indexName + ".ix")), new Tfidf()))
{
var scores = collector.Collect(new QueryContext("_id", "3")).ToList();
Assert.AreEqual(1, scores.Count);
Assert.IsTrue(scores.Any(d => d.DocumentId == 3));
}
using (var collector = new Collector(dir, IxInfo.Load(Path.Combine(dir, indexName + ".ix")), new Tfidf()))
{
var scores = collector.Collect(new QueryContext("_id", "5five")).ToList();
Assert.AreEqual(1, scores.Count);
Assert.IsTrue(scores.Any(d => d.DocumentId == 5));
}
}
public static IEnumerable <IList <DocumentPosting> > ReadPostings(string directory, IxInfo ix, IEnumerable <Term> terms)
{
var posFileName = Path.Combine(directory, String.Format("{0}.{1}", ix.VersionId, "pos"));
var addresses = terms.Select(term => term.Word.PostingsAddress.Value).OrderBy(adr => adr.Position).ToList();
using (var reader = new PostingsReader(new FileStream(posFileName, FileMode.Open, FileAccess.Read, FileShare.Read, 4096 * 1, FileOptions.SequentialScan)))
{
var postings = reader.Get(addresses).SelectMany(x => x).ToList();
yield return(postings);
}
}
