diff --git a/autotests/benchmarks/positioncodecbenchmark.cpp b/autotests/benchmarks/positioncodecbenchmark.cpp
--- a/autotests/benchmarks/positioncodecbenchmark.cpp
+++ b/autotests/benchmarks/positioncodecbenchmark.cpp
@@ -31,28 +31,36 @@
     Q_OBJECT
 private Q_SLOTS:
     void initTestCase();
-    // data 1 - a lot of positions, small amount of PositionInfo
+    // data 1 - small number of documents, each with many positions
     void benchEncodeData1();
     void benchDecodeData1();
-    // data 2 - few positions, large amount of PositionInfo
+    // data 2 - large number of documents, few positions (10) each
     void benchEncodeData2();
     void benchDecodeData2();
+    // data 3 - small number of documents, many positions with large increment
+    void benchEncodeData3();
+    void benchDecodeData3();
 private:
     QVector<PositionInfo> m_benchmarkData1;
     QVector<PositionInfo> m_benchmarkData2;
+    QVector<PositionInfo> m_benchmarkData3;
 };
 
 void PositionCodecBenchmark::initTestCase()
 {
+    /*
+     * Same dataset as in autotests/unit/codecs/positioncodectest.cpp
+     * Correctness of encoding/decoding is checked there.
+     */
     m_benchmarkData1.clear();
     m_benchmarkData1.reserve(100);
     for(int i = 0; i < 100; ++i)
     {
         PositionInfo info;
         info.docId = (i + 1) * 4711;
         info.positions.reserve(3000);
         for (int j = 0; j < 3000; j++)
-            info.positions.append(((j + 1) * 42) / info.docId);
+            info.positions.append(((j + 1) * (i + 2)));
         m_benchmarkData1.append(info);
     }
 
@@ -66,6 +74,17 @@
         m_benchmarkData2.append(info);
     }
 
+    m_benchmarkData3.clear();
+    m_benchmarkData3.reserve(200);
+    for (int i = 0; i < 200; i++) {
+        PositionInfo info;
+        info.docId = i;
+        info.positions.reserve(30000); // > 2^14 -> 3 byte VarInt32
+        for (int j = 0; j < 30000; j++)
+            info.positions.append((j + 1) * 200); // increment 200 -> 2 byte DiffVarInt32
+
+        m_benchmarkData3.append(info);
+    }
 }
 
 void PositionCodecBenchmark::benchEncodeData1()
@@ -94,6 +113,19 @@
     QBENCHMARK { pc.decode(ba); }
 }
 
+void PositionCodecBenchmark::benchEncodeData3()
+{
+    PositionCodec pc;
+    QBENCHMARK { pc.encode(m_benchmarkData3); }
+}
+
+void PositionCodecBenchmark::benchDecodeData3()
+{
+    PositionCodec pc;
+    const QByteArray ba = pc.encode(m_benchmarkData3);
+    QBENCHMARK { pc.decode(ba); }
+}
+
 QTEST_MAIN(PositionCodecBenchmark)
 
 #include "positioncodecbenchmark.moc"
diff --git a/autotests/unit/codecs/positioncodectest.cpp b/autotests/unit/codecs/positioncodectest.cpp
--- a/autotests/unit/codecs/positioncodectest.cpp
+++ b/autotests/unit/codecs/positioncodectest.cpp
@@ -35,8 +35,12 @@
 private Q_SLOTS:
     void initTestCase();
     void checkEncodeOutput();
+    void checkEncodeOutput2();
+    void checkEncodeOutput3();
 private:
     QVector<PositionInfo> m_data;
+    QVector<PositionInfo> m_data2;
+    QVector<PositionInfo> m_data3;
 };
 
 QTEST_MAIN ( PositionCodecTest )
@@ -51,21 +55,67 @@
         info.docId = (i + 1) * 4711;
         info.positions.reserve(3000);
         for (int j = 0; j < 3000; j++)
-            info.positions.append(((j + 1) * 42) / info.docId);
+            info.positions.append((j + 1) * (i * 2));
         m_data.append(info);
     }
+
+    m_data2.clear();
+    m_data2.reserve(5000);
+    for (int i = 0; i < 5000; i++) {
+        PositionInfo info;
+        info.docId = i;
+        info.positions = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+
+        m_data2.append(info);
+    }
+
+    m_data3.clear();
+    m_data3.reserve(200);
+    for (int i = 0; i < 200; i++) {
+        PositionInfo info;
+        info.docId = i;
+        info.positions.reserve(30000); // > 2^14 -> 3 byte VarInt32
+        for (int j = 0; j < 30000; j++)
+            info.positions.append((j + 1) * 200); // increment 200 -> 2 byte DiffVarInt32
+
+        m_data3.append(info);
+    }
 }
 
 void PositionCodecTest::checkEncodeOutput()
 {
     PositionCodec pc;
     const QByteArray ba = pc.encode(m_data);
-    QCOMPARE(ba.size(), 301000);
+    QCOMPARE(ba.size(), 409000);
     const QByteArray md5 = QCryptographicHash::hash(ba, QCryptographicHash::Md5).toHex();
-    QCOMPARE(md5, QByteArray("d44a606d301937bef105411c0ee77a88"));
+    QCOMPARE(md5, QByteArray("ae49eb3279bdda36ef91d29ce3c94c2c"));
     // and now decode the whole stuff
     QVector<PositionInfo> decodedData = pc.decode(ba);
     QCOMPARE(m_data, decodedData);
 }
 
+void PositionCodecTest::checkEncodeOutput2()
+{
+    PositionCodec pc;
+    const QByteArray ba = pc.encode(m_data2);
+    QCOMPARE(ba.size(), (8 + 1 + 10) * 5000); // DocId, VarInt32 len, DiffVarInt position
+    const QByteArray md5 = QCryptographicHash::hash(ba, QCryptographicHash::Md5).toHex();
+    QCOMPARE(md5, QByteArray("2f3710246331002e2332dce560ccd783"));
+    // and now decode the whole stuff
+    QVector<PositionInfo> decodedData = pc.decode(ba);
+    QCOMPARE(m_data2, decodedData);
+}
+
+void PositionCodecTest::checkEncodeOutput3()
+{
+    PositionCodec pc;
+    const QByteArray ba = pc.encode(m_data3);
+    QCOMPARE(ba.size(), (8 + 3 + (2 * 30000)) * 200); // DocId, VarInt32 len, DiffVarInt position
+    const QByteArray md5 = QCryptographicHash::hash(ba, QCryptographicHash::Md5).toHex();
+    QCOMPARE(md5, QByteArray("79e942003c082073b4cee8e376fffdaa"));
+    // and now decode the whole stuff
+    QVector<PositionInfo> decodedData = pc.decode(ba);
+    QCOMPARE(m_data3, decodedData);
+}
+
 #include "positioncodectest.moc"