[
https://issues.apache.org/jira/browse/CASSANDRA-12884?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=1614#comment-1614
]
Jeff Jirsa edited comment on CASSANDRA-12884 at 8/10/17 8:34 PM:
-
[~iamaleksey] will have a more comprehensive review, I'm sure, but a few notes
from a very cursory glance:
-1) I don't see the purpose of stubbing out {{BatchlogManager::shuffle}} as a
helper function here.- (You're overriding it for deterministic testing)
2) In the case where {{validated.keySet().size() == 1}} , shuffling all of the
IPs in a given rack may not be all that efficient - may be quicker to just pick
2 random ints, and grab the IPs at those offsets (like we do for the case where
we have more than 2 racks,
{{result.add(rackMembers.get(getRandomInt(rackMembers.size(;}} )
was (Author: jjirsa):
[~iamaleksey] will have a more comprehensive review, I'm sure, but a few notes
from a very cursory glance:
1) I don't see the purpose of stubbing out {{BatchlogManager::shuffle}} as a
helper function here.
2) In the case where {{validated.keySet().size() == 1}} , shuffling all of the
IPs in a given rack may not be all that efficient - may be quicker to just pick
2 random ints, and grab the IPs at those offsets (like we do for the case where
we have more than 2 racks,
{{result.add(rackMembers.get(getRandomInt(rackMembers.size(;}} )
> Batch logic can lead to unbalanced use of system.batches
>
>
> Key: CASSANDRA-12884
> URL: https://issues.apache.org/jira/browse/CASSANDRA-12884
> Project: Cassandra
> Issue Type: Bug
> Components: Core
>Reporter: Adam Hattrell
>Assignee: Daniel Cranford
> Fix For: 3.0.x, 3.11.x
>
> Attachments: 0001-CASSANDRA-12884.patch
>
>
> It looks as though there are some odd edge cases in how we distribute the
> copies in system.batches.
> The main issue is in the filter method for
> org.apache.cassandra.batchlog.BatchlogManager
> {code:java}
> if (validated.size() - validated.get(localRack).size() >= 2)
> {
> // we have enough endpoints in other racks
> validated.removeAll(localRack);
> }
> if (validated.keySet().size() == 1)
> {
>// we have only 1 `other` rack
>Collection otherRack =
> Iterables.getOnlyElement(validated.asMap().values());
>
> return Lists.newArrayList(Iterables.limit(otherRack, 2));
> }
> {code}
> So with one or two racks we just return the first 2 entries in the list.
> There's no shuffle or randomisation here.
--
This message was sent by Atlassian JIRA
(v6.4.14#64029)
-
To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org
For additional commands, e-mail: commits-h...@cassandra.apache.org
