[
https://issues.apache.org/jira/browse/CASSANDRA-10699?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16881823#comment-16881823
]
vincent royer commented on CASSANDRA-10699:
-------------------------------------------
Currently (in v3.11.4), each DDL statement involves a schema mutation, and you
cannot validate a statement without applying the previous one (ex: CREATE TYPE
A, CREATE TYPE B, CREATE TABLE (a A, b B)), As the result, a DDL script
generate a storm of single schema updates for all nodes rather than a batched
schema update.
If it can help, we have done some improvements in our cassandra to manage batch
schema update in a transaction. This means that we can validate several schema
changes on a working copy of the current schema and apply these changes in one
update broadcasted to all nodes (one mutation for several DDL statements).
We've done that for Elassandra, and Elassandra also plays a PAXOS transaction
to update the elasticsearch mapping, so CQL schema updates resulting of an
Elasticsearch mapping update are serialized, and applied in one batch update
after validation on a working copy of the schema. It does not fully solve this
issue for Cassandra, but it solves it when you update the CQL schema through
the Elasticsearch mapping.
Here is our commit about that work available on
[commit1|https://github.com/strapdata/cassandra/commit/d7b7844a6d25f7d42d68e4abd1d89c4e92049545]
[commit2|https://github.com/strapdata/cassandra/commit/46cfaa8ac158f4e35078265667e3574719117eb3]
> Make schema alterations strongly consistent
> -------------------------------------------
>
> Key: CASSANDRA-10699
> URL: https://issues.apache.org/jira/browse/CASSANDRA-10699
> Project: Cassandra
> Issue Type: Sub-task
> Components: Legacy/Distributed Metadata
> Reporter: Aleksey Yeschenko
> Assignee: Aleksey Yeschenko
> Priority: Normal
> Fix For: 4.x
>
>
> Schema changes do not necessarily commute. This has been the case before
> CASSANDRA-5202, but now is particularly problematic.
> We should employ a strongly consistent protocol instead of relying on
> marshalling {{Mutation}} objects with schema changes.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
