Cassandra 4.5 driver issue with @Entity and Counter fields

Question

Having a problem with the 4.5 Datastax Cassandra driver. I cannot get any of these @Queries to work:

@Dao
public interface SampleTable2Dao extends BaseDao<SampleTable2> {
    //@Query("UPDATE sampletable2 SET cntrfld = cntrfld + :toAdd WHERE key1 = :key1Value AND key2 = :key2Value AND key3 = :key3Value")
    @Query("UPDATE sampletable2 SET cntrfld = cntrfld + 1 WHERE key1 = 1 AND key2 = 1 AND key3 = 1;")
    CompletableFuture<Void> addCountAsync(int toAdd, int key1Value, int key2Value, int key3Value);

    @Query("UPDATE sampletable2 SET cntrfld = cntrfld + 1 WHERE key1 = 1 AND key2 = 1 AND key3 = 1;")
    void addCount(int toAdd, int key1Value, int key2Value, int key3Value);

    @Query("UPDATE sampletable2 SET cntrfld = cntrfld + 1 WHERE key1 = 1 AND key2 = 1 AND key3 = 1;")
    void addCount();

It simply hangs: getSampleTable2Dao().addCount();

The queries work fine directly in Cassandra.

Thanks

P.S. here is the table for anyone wants to test:

CREATE TABLE sampletable2 (
    key1 int,
    key2 int,
    key3 int,
    cntrfld counter,
    PRIMARY KEY (key1, key2, key3)
);

update #1

After some digging, I find that it's in this generated code where it's hanging. Nothing to do with the actual query:

this.sampleTable2DaoCache = new LazyReference<>(() -> SampleTable2DaoImpl__MapperGenerated.init(context));

  @Override
  public SampleTable2Dao sampleTable2Dao() {
    return sampleTable2DaoCache.get();
  }

I'm working my way backwards stripping things out until I can get it working. Other DAOs work fine - the only difference with this is the counter field.

UPDATE #2... the "real" issue, is not @Query at all... but @Entity with counter fields.

@CqlName("cntrfld")
private Long cntrFld;

If this field is a counter in Cassandra (3.11.4 btw) the code just hangs. If I make the field a bigint, it works just fine!

It works for me. How are you building your session? One potential issue is that there is no keyspace in the query string, so your session needs to have a default one (`CqlSession.builder().withKeyspace(...)`). But still a missing keyspace should produce an error, not hang. — Olivier Michallat, Apr 02 '20 at 16:40
That's not the issue... I cannot get it to connect without the keyspace... and it can connect. I have another dao working just fine. — Jason Nethercott, Apr 02 '20 at 18:27
I tried 4.5.1, and it is still broken. I'm at a stand-still... Seems i cannot use a counter field with mappers. — Jason Nethercott, Apr 02 '20 at 19:32

Olivier Michallat · Answer 1 · 2020-04-02T20:14:32.563

I think you're trying to use @Insert or @Update with a counter column. That won't work: counters are a special type of column, they only support increment or decrement operations.

You can use an entity for read or delete operations though. But for updates, @Query is your only option right now:

@Entity @CqlName("sampletable2")
public class SampleTable2 {
  @PartitionKey private int key1;
  @ClusteringColumn(1) private int key2;
  @ClusteringColumn(2) private int key3;
  private long cntrfld;
  // getters and setters...
}

@Dao
public interface SampleTable2Dao {
  @Select
  SampleTable2 get(int key1, int key2, int key3);

  @Delete
  void delete(SampleTable2 entity);

  @Query(
      "UPDATE sampletable2 SET cntrfld = cntrfld + 1 "
          + "WHERE key1 = :key1 AND key2 = :key2 AND key3 = :key3")
  void increment(int key1, int key2, int key3);

  // THIS WON'T WORK:
  // @Insert
  // void insert(SampleTable2 entity);
}

Admittedly, we could have better support for counters in the mapper. I think something like this could work:

  @Increment
  void increment(SampleTable2 entity);

I've created JAVA-2721 to explore the idea.

Actually... my BaseDao does have an Insert... maybe that's it. I'll try to remove it. It should throw an error though, not just hang forever. just a thought. ;) — Jason Nethercott, Apr 02 '20 at 22:28
I like the idea of an @ Increment. BUT, you need to be able to control the number to increment. I.E. @ Increment void increment(SampleTable2 entity, long delta); Or, would you have the code put the delta number in the entity variable field before calling? — Jason Nethercott, Apr 03 '20 at 11:44
Yes, we'll have to refine the API a little bit: different increments (including negative), multiple counters, etc. — Olivier Michallat, Apr 03 '20 at 17:09

score 1 · Answer 2 · answered Apr 03 '20 at 11:41

1

The error was, my @Dao had an @Insert, but the table used a counter field type. Once I removed the @Insert, then the system worked.

I followed the help and created a BaseDao< T > class that contained repetitive @Insert and @Delete sets of methods, so it wasn't obvious what I had wrong.

The library SHOULD throw an error in this situation, and not just hang... that's a bug int he library I think.

answered Apr 03 '20 at 11:41

Jason Nethercott

373
3
20

I am getting an error by the way: `com.datastax.oss.driver.api.core.servererrors.InvalidQueryException: INSERT statements are not allowed on counter tables, use UPDATE instead` when I get the DAO from the mapper. There might be something else going on, try debugging maybe. – Olivier Michallat Apr 03 '20 at 17:24

Cassandra 4.5 driver issue with @Entity and Counter fields

2 Answers2