[CASSANDRA-5563] The CQL3 binary protocol does not allow a user to bind an empty buffer to signify the start of the token range

• Type: Bug
• Status: Resolved
• Priority: Low
• Resolution: Cannot Reproduce
• Component/s: Legacy/CQL
• Severity: Low
• Assignee: Sylvain Lebresne
• Reporter: Steven Lowenthal

Authors

Sylvain Lebresne

• Created: 13/May/13 19:18
• Updated: 16/Apr/19 09:32
• Resolved: 09/Jul/13 15:04

Description

Using CQL2 or CQL3 over thrift, one can issue a query which starts at the beginning of the table by binding an empty buffer. The same is true for CQL2 using calls like get_range_slice. This is not allowed with the binary protocol. Here is working sample code for CQL3 over thrift:

    CqlPreparedResult stmt = _client.prepare_cql3_query(ByteBuffer.wrap("SELECT \" Sequence number\" from \"nhanes52simple\" where TOKEN (\" Sequence number\") > TOKEN(?) limit 15".getBytes()), Compression.NONE);

    // Bind empty buffer to get query to start at the beginning of 
    // the table
    ByteBuffer b = ByteBuffer.wrap(new byte[0]);
    bindVars.add(b);

    int cnt = 0;
    CqlResult result;

    do {
      result =  _client.execute_prepared_cql3_query(stmt.itemId, bindVars, ConsistencyLevel.ONE);
      // Set up the next chunk, by setting the bind var to the last received key
      bindVars.set(0, ByteBuffer.wrap(result.getRows()
              .get(result.getRows().size() - 1).getColumns().get(0).getValue()));

      // Count rows
      cnt += result.getRows().size();

      if (cnt > 100)
        Assert.fail("Running past the end of the table: cnt = " + cnt + ", size() =  " + result.getRows().size());

    } while (result.getRows().size() >= CHUNK_SIZE);

    Assert.assertEquals("Wrong count", 100, cnt);

  }