Scylla: Aggregation of counters

[tkozybski]

Installation details
Scylla version (or git commit hash): 2.1-rc2

Hello. I noticed that aggregation functions doesn't work on counters. I don't see any reason this shouldn't be possible.

How to reproduce:

CREATE TABLE test (
        key INT,
        ctr COUNTER,
        PRIMARY KEY (
                key
        )
);

UPDATE test SET ctr = ctr + 1 WHERE key = 1;
SELECT SUM(ctr) FROM test;

Result

InvalidRequest: Error from server: code=2200 [Invalid query] message="Invalid call to function sum, none of its type signatures match (known type signatures: system.sum : (org.apache.cassandra.db.marshal.DecimalType) -> org.apache.cassandra.db.marshal.DecimalType, system.sum : (org.apache.cassandra.db.marshal.IntegerType) -> org.apache.cassandra.db.marshal.IntegerType, system.sum : (org.apache.cassandra.db.marshal.DoubleType) -> org.apache.cassandra.db.marshal.DoubleType, system.sum : (org.apache.cassandra.db.marshal.FloatType) -> org.apache.cassandra.db.marshal.FloatType, system.sum : (org.apache.cassandra.db.marshal.LongType) -> org.apache.cassandra.db.marshal.LongType, system.sum : (org.apache.cassandra.db.marshal.Int32Type) -> org.apache.cassandra.db.marshal.Int32Type, system.sum : (org.apache.cassandra.db.marshal.ShortType) -> org.apache.cassandra.db.marshal.ShortType, system.sum : (org.apache.cassandra.db.marshal.ByteType) -> org.apache.cassandra.db.marshal.ByteType)"

I also tried casting
SELECT SUM(CAST(ctr as bigint)) FROM test
but it's not working either

Error from server: code=2200 [Invalid query] message="org.apache.cassandra.db.marshal.CounterColumnType cannot be cast to org.apache.cassandra.db.marshal.LongType"

[tzach]

@pdziepak ?

[slivne]

@penberg / @pdziepak ?

check it works on cassandra 2.2.9

[pdziepak]

Looks like it was added in [1]. No reason not to implement this in Scylla as well. If I remember correctly at this stage counters are already treated as bigint values (and not sets of counter shards) so supporting aggregating them shouldn't be very difficult.

[1] https://issues.apache.org/jira/browse/CASSANDRA-9977

[antsmc2]

Was issue fixed in the latest release (2.3.rc1)? I'm using 2.2.0 and still facing this issue.

[tzach]

@antsmc2 issue is not fixed yet. Once it does, you should see a commit link in the comments

[noamguy]

Any news regarding sum on counter fields?

[jimmykuo]

Any updates on this ? 🙏

[tzach]

@jimmykuo no news yet. Waiting for a brave volunteer to send a PR

[mrsinham]

Need this one as well

[slivne]

@haaawk / @jul-stas - its a feature related to counters - so queue this up for you guys.

[gnumoreno]

Reproducer:

CREATE KEYSPACE test WITH REPLICATION = { 'class' : 'SimpleStrategy', 'replication_factor' : 1 };
CREATE TABLE test.wsgcounter ( countername text PRIMARY KEY, counterval counter );
UPDATE wsgcounter SET counterval = counterval + 1 WHERE countername = 'bla';
UPDATE wsgcounter SET counterval = counterval + 10 WHERE countername = 'ble';
UPDATE wsgcounter SET counterval = counterval + 100 WHERE countername = 'bli';
select cast(counterval as varchar) from wsgcounter where countername='bla';

[slivne]

@gnumoreno its casting not a sum function, why do you need to cast the value (in this case it was an attempt to make the value an int that can be summed.

[gnumoreno]

@slivne the original poster also mentioned casting, please check the first post on the thread.

[jul-stas]

Aggregation is already solved and merged to master: https://github.com/scylladb/scylla/pull/5632 . (GH somehow didn't close this issue...)
Rearding casts: currently only implicit cast to long is supported. If we need other casts let's open a new issue and talk about it.

[slivne]

fixed by https://github.com/scylladb/scylla/commit/127e258adeb044873d20606b82fc1f1d7e62d34b