[
https://issues.apache.org/jira/browse/CASSANDRA-14062?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16277483#comment-16277483
]
Ariel Weisberg commented on CASSANDRA-14062:
--------------------------------------------
Thanks for posting this.
In the email thread you mentioned that you were going to change the commit log
format? How does the commit log replayer interact with commit logs written by
other providers?
What do you think of passing the Cassandra version string into the commit log
provider constructor so the commit log provider can validate it's a version the
provider was compiled and tested for? It would also allow the plugin to work
with multiple versions of Cassandra and implement work arounds for any
problematic interactions between the two.
> Pluggable CommitLog
> -------------------
>
> Key: CASSANDRA-14062
> URL: https://issues.apache.org/jira/browse/CASSANDRA-14062
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Rei Odaira
> Assignee: Rei Odaira
> Labels: features
> Fix For: 4.x
>
> Attachments: pluggable-commitlog-src.patch,
> pluggable-commitlog-test.patch
>
>
> This proposal is to make CommitLog pluggable, as discussed in [the Cassandra
> dev mailing
> list|https://lists.apache.org/thread.html/1936194d86f5954fa099ced9a0733458eb3249bff3fae3e03e2d1bd8@%3Cdev.cassandra.apache.org%3E].
> We are developing a Cassandra plugin to store CommitLog on our low-latency
> Flash device (CAPI-Flash). To do that, the original CommitLog interface must
> be changed to allow plugins. Synching to CommitLog is one of the performance
> bottlenecks in Cassandra especially with batch commit. I think the pluggable
> CommitLog will allow other interesting alternatives, such as one using SPDK.
> Our high-level design is similar to the CacheProvider framework
> in org.apache.cassandra.cache:
> * Introduce a new interface, ICommitLog, with methods like
> getCurrentPosition(), add(), shutdownBlocking(), etc.
> * CommitLog implements ICommitLog.
> * Introduce a new interface, CommitLogProvider, with a create() method,
> returning ICommitLog.
> * Introduce a new class FileCommitLogProvider implementing CommitLogProvider,
> to return a singleton instance of CommitLog.
> * Introduce a new property in cassandra.yaml, commitlog_class_name, which
> specifies what CommitLogProvider to use. The default is
> FileCommitLogProvider.
> * Introduce a new class, CommitLogHelper, that loads the class specified by
> the commitlog_class_name property, creates an instance, and stores it to
> CommitLogHelper.instance.
> * Replace all of the references to CommitLog.instance with
> CommitLogHelper.instance.
> Attached are two patches. "pluggable-commitlog-src.patch" is for changes in
> the src directory, and "pluggable-commitlog-test.patch" is for the test
> directory.
--
This message was sent by Atlassian JIRA
(v6.4.14#64029)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
