[
https://issues.apache.org/jira/browse/CASSANDRA-16878?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17494371#comment-17494371
]
Yifan Cai commented on CASSANDRA-16878:
---------------------------------------
Thanks for the example... I agree with you that the scenario can happen.
During schema
[transform|https://github.com/apache/cassandra/blob/trunk/src/java/org/apache/cassandra/schema/Schema.java#L644-L646],
applying the schema change mutations and adding to the commit log happens
before merging the diff to update the schema instance. It is possible that a
mutation is created with the correct table metadata, but the DropTable mutation
has just been added to the commit log. (And appears before the regular mutation
in the commit log)
What do you think about merging before applying the schema change mutations?
> Race in commit log replay can cause rejected mutations
> ------------------------------------------------------
>
> Key: CASSANDRA-16878
> URL: https://issues.apache.org/jira/browse/CASSANDRA-16878
> Project: Cassandra
> Issue Type: Bug
> Components: Legacy/Local Write-Read Paths
> Reporter: Andres de la Peña
> Assignee: Andres de la Peña
> Priority: Normal
> Fix For: 3.0.x, 3.11.x, 4.0.x, 4.x
>
> Time Spent: 3h 10m
> Remaining Estimate: 0h
>
> We don't force order in the execution of replayed mutations and hence a
> mutation can move ahead of or behind a schema change it relies on (e.g.
> added/removed column), which can then cause it to be rejected because of a
> schema mismatch.
> To fix this, we need to identify schema mutations and make sure the log
> enforces their execution after all previous mutations have completed and
> before anything following is started.
> Schema mutations are
> [flushed|https://github.com/apache/cassandra/blob/cassandra-4.0.0/src/java/org/apache/cassandra/schema/SchemaKeyspace.java#L1266-L1271]
> after being applied, so this only would be a problem if the node abruptly
> stops before flushing the schema mutation.
--
This message was sent by Atlassian Jira
(v8.20.1#820001)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
