Hi Solr people,
I am writing a custom UpdateProcessor, part of a custom plugin, and need to run
some code only on the shard leader. This is a plugin, so I cannot access the
DistributedUpdateProcessor.isLeader() method which is not public.
For now I am copying-pasting the below code, but I am thinking there's got to
be a better way to do it.
private boolean getIsLeader() {
final boolean isZkAware =
req.getCore().getCoreContainer().isZooKeeperAware();
if (!isZkAware) {
return getNonZkLeaderAssumption(req);
}
String shardId = cloudDesc.getShardId();
try {
Replica leaderReplica =
zkController.getZkStateReader().getLeaderRetry(collection, shardId);
return leaderReplica.getName().equals(cloudDesc.getCoreNodeName());
}
catch (InterruptedException e) {
throw new ZooKeeperException(SolrException.ErrorCode.SERVER_ERROR,
“Error TODO", e);
}
}
I think there is also another way to do it using cloudDesc.isLeader() but my
understanding, if I am not wrong, is that the first code gives the most
accurate state. Am I right? Is this the only way to get the most accurate state
about the current leader?
Also, should I run it every time I need to check the current status as the
leader can change anytime? What's the impact in terms of performance?
Thank you for your help in advance.
Lamine
