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DOAN DuyHai edited comment on CASSANDRA-6668 at 2/25/14 10:08 AM: ------------------------------------------------------------------ bq. we should probably reject TTL = 0 Please don't. bq. but it's perfectly possible that someone uses a prepared statement with a bind marker for the TTL, sometimes binding a strictly positive TTL and sometimes binding 0 to get no expiration It's the case for *Achilles*. It prepares a bunch of Insert/Update statements before-hand with TTL and just set strictly positive value when there is an TTLed insert/update bq. my preferred semantic (all notion of backward compatibility aside) would be to just never insert a row marker in UPDATE +1 for that. Although I'm quite familiar with CQL3, I got caught with the TTL subtlety related to the row TTL marker. I guess lots of people will also get caught too on it. was (Author: doanduyhai): bq. we should probably reject TTL = 0 Please don't. bq. but it's perfectly possible that someone uses a prepared statement with a bind marker for the TTL, sometimes binding a strictly positive TTL and sometimes binding 0 to get no expiration It's the case for **Achilles**. It prepares a bunch of Insert/Update statements before-hand with TTL and just set strictly positive value when there is an TTLed insert/update bq. my preferred semantic (all notion of backward compatibility aside) would be to just never insert a row marker in UPDATE +1 for that. Although I'm quite familiar with CQL3, I got caught with the TTL subtlety related to the row TTL marker. I guess lots of people will also get caught too on it. > Inconsistent handling of row expiration using TTL in collections > ---------------------------------------------------------------- > > Key: CASSANDRA-6668 > URL: https://issues.apache.org/jira/browse/CASSANDRA-6668 > Project: Cassandra > Issue Type: Bug > Components: Core > Environment: Apache Cassandra 2.0.3 > Apache Cassandra 1.2.8 > CQLSH client 3.1.6 > Reporter: DOAN DuyHai > Priority: Critical > > The expiration of row when all TTLed columns have expired is inconsistent > Scenario 1) > {code:sql} > cqlsh:test> create table ttl_issue(id int primary key,collection set<text>); > cqlsh:test> update ttl_issue USING TTL 2 set collection = collection + > {'test_2'} where id=10; > cqlsh:test> update ttl_issue USING TTL 3 set collection = collection + > {'test_3'} where id=10; > cqlsh:test> select * from ttl_issue; > id | collection > ----+---------------------- > 10 | {'test_2', 'test_3'} > cqlsh:test> select * from ttl_issue; > id | collection > ----+---------------------- > 10 | {'test_2', 'test_3'} > cqlsh:test> select * from ttl_issue; > id | collection > ----+------------ > 10 | {'test_3'} > cqlsh:test> select * from ttl_issue; > cqlsh:test> > {code} > As we can see, after a few seconds, both columns of the collection are > expired. When all columns of the set have expired, the SELECT * FROM > ttl_issue *returns no result, meaning that the whole row has expired.* > Scenario 2) > {code:sql} > cqlsh:test> update ttl_issue USING TTL 3 set collection = collection + > {'test_3'} where id=11; > cqlsh:test> update ttl_issue USING TTL 1000 set collection = collection + > {'test_1000'} where id=11; > cqlsh:test> update ttl_issue set collection = collection - {'test_1000'} > where id=11; > cqlsh:test> select * from ttl_issue; > id | collection > ----+------------ > 11 | {'test_3'} > cqlsh:test> select * from ttl_issue; > id | collection > ----+------------ > 11 | {'test_3'} > cqlsh:test> select * from ttl_issue; > id | collection > ----+------------ > 11 | {'test_3'} > cqlsh:test> select * from ttl_issue; > id | collection > ----+------------ > 11 | null > {code} > In this second scenario. We add elements to the collection with TTL but then > remove one of them. *After a while, although all TTLed columns have expired, > the row is till there with only the primary key present.* > One should expect to get the same behavior as in scenario 1), e.g. the > complete row should expire. > I've also tried removing one element from collection using TTL 0 > ({code:sql}update ttl_issue USING TTL 0 set collection = collection - > {'test_1000'} where id=11;{code}) but the result is the same. > Quick guest: bug on row deletion marker for specific collection element > append/remove ? -- This message was sent by Atlassian JIRA (v6.1.5#6160)