[
https://issues.apache.org/jira/browse/SOLR-8973?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15241923#comment-15241923
]
Scott Blum edited comment on SOLR-8973 at 4/14/16 9:16 PM:
-----------------------------------------------------------
[~shalinmangar] I've come to the conclusion that ZkStateReader isn't doing as
well as it could be. Adding watchers in constructState() seems (retroactively)
like a hack. It doesn't correctly cover the case where a collection parent
node exists (e.g. /solr/collections/coll1) but no state.json child yet appears.
I believe I have a patch and test to fix this. Attached it to this JIRA, but
not sure if I should create a new one.
was (Author: dragonsinth):
[~shalinmangar] I've come to the conclusion that ZkStateReader isn't doing as
well as it could be. Adding watchers in constructState() seems (retroactively)
like a hack. It doesn't correctly cover the case where a collection parent
node exists (e.g. /solr/collections/coll1) but no state.json child yet appears.
I believe I have a patch and test to fix this. Not sure whether I should
attach to this JIRA or create a new one.
> TX-frenzy on Zookeeper when collection is put to use
> ----------------------------------------------------
>
> Key: SOLR-8973
> URL: https://issues.apache.org/jira/browse/SOLR-8973
> Project: Solr
> Issue Type: Bug
> Components: SolrCloud
> Affects Versions: 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, master, 5.6
> Reporter: Janmejay Singh
> Assignee: Shalin Shekhar Mangar
> Labels: collections, patch-available, solrcloud, zookeeper
> Attachments: SOLR-8973-ZkStateReader.patch, SOLR-8973.patch
>
>
> This is to do with a distributed data-race. Core-creation happens at a time
> when collection is not yet visible to the node. In this case a fallback
> code-path is used which de-references collection-state lazily (on demand) as
> opposed to setting a watch and keeping it cached locally.
> Due to this, as requests towards the core mount, it generates ZK fetch for
> collection proportionately. On a large solr-cloud cluster, this generates
> several Gbps of TX traffic on ZK nodes. This affects indexing
> throughput(which floors) in addition to running ZK node out of network
> bandwidth.
> On smaller solr-cloud clusters its hard to run into, because probability of
> this race materializing reduces.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org
For additional commands, e-mail: dev-h...@lucene.apache.org
