[jira] [Commented] (CASSANDRA-19764) Corruption can occur while a field is being added to UDT clustering key

["Caleb Rackliffe (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-19764?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17865170#comment-17865170 ] 

Caleb Rackliffe commented on CASSANDRA-19764:
---------------------------------------------

So to be clear, this should reproduce on {{trunk}} as...

{noformat}
@Test
public void testDivergentSchemas() throws Throwable
{
    try (Cluster cluster = init(Cluster.create(2)))
    {
        cluster.schemaChange("create type " + KEYSPACE + ".a (foo text)");
        cluster.schemaChange("create table " + KEYSPACE + ".x (id int, ck frozen<a>, i int, primary key (id, ck))");
        cluster.filters().verbs(Verb.TCM_REPLICATION.id).drop().on();
        cluster.coordinator(1).execute("alter type " + KEYSPACE + ".a add bar text", ConsistencyLevel.QUORUM);
        cluster.coordinator(1).execute("insert into " + KEYSPACE + ".x (id, ck, i) VALUES (?, " + json(1, 2) + ", ? )", ConsistencyLevel.ALL, 1, 2);
        cluster.coordinator(1).execute("insert into " + KEYSPACE + ".x (id, ck, i) VALUES (?, " + json(1, 1) + ", ? )", ConsistencyLevel.ALL, 1, 1);
        cluster.get(2).flush(KEYSPACE);

        Object[][] res1 = cluster.coordinator(1).execute("select i from " + KEYSPACE + ".x WHERE id = 1", ConsistencyLevel.ALL);
        Object[][] res2 = cluster.coordinator(2).execute("select i from " + KEYSPACE + ".x WHERE id = 1", ConsistencyLevel.ALL);

        assertArrayEquals(res1, res2);
    }
}
{noformat}

Not able to get a failure, but perhaps I'm missing something. Either way, it seems like a bad idea to allow altering UDTs once they are part of a primary key...

> Corruption can occur while a field is being added to UDT clustering key
> -----------------------------------------------------------------------
>
>                 Key: CASSANDRA-19764
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-19764
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Feature/UDT
>            Reporter: Branimir Lambov
>            Priority: Normal
>
> CASSANDRA-15938 made some improvements in how unknown components in UDTs are treated. Unfortunately this can cause corruption as soon as more than one value is inserted for a partition.
> The problem can be easily shown by modifying the {{FrozenUDTTest.testDivergentSchema}} test to insert two entries in the wrong order:
> {code:java}
> cluster.coordinator(1).execute("insert into " + KEYSPACE + ".x (id, ck, i) VALUES (?, " + json(1, 2) + ", ? )", ConsistencyLevel.ALL,
> 1, 2);
> cluster.coordinator(1).execute("insert into " + KEYSPACE + ".x (id, ck, i) VALUES (?, " + json(1, 1) + ", ? )", ConsistencyLevel.ALL,
> 1, 1);
> {code}
> after which we can get corrupted sstable state, shown as a
> {code:java}
> java.lang.AssertionError: Lower bound [SSTABLE_LOWER_BOUND(1) ]is bigger than first returned value [Row: ck=1 | i=2]
> {code}
> exception, or results like {{[[1],[2],[2],[1]]}} or {{[[2],[1],[2]]}} for {{select i from x WHERE id = 1}} depending on which node we use as coordinator.
> Because we don't know the type of new fields and cannot properly order entries, we need to outright reject UDT keys that are not compatible with a replica's schema.



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