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https://issues.apache.org/jira/browse/HDDS-1175?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16781835#comment-16781835
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Yiqun Lin edited comment on HDDS-1175 at 3/2/19 10:06 AM:
----------------------------------------------------------
Hi [~hanishakoneru], just take a quick review, some comments from me: I think
we can make {{ROLE_CHECK_INTERVAL}} configurable. In some scenarios, admins
maybe want to let cache leader id be more-updated.
Another place, it would be better to have a check to verify that proxy provider
has real performed fail-over to current leader id. Then we then call retry
behaviour.
{code}
if (cause instanceof NotLeaderException) {
NotLeaderException notLeaderException = (NotLeaderException) cause;
omFailoverProxyProvider.performFailoverIfRequired(
notLeaderException.getSuggestedLeaderNodeId());
// we need a check here that if omFailoverProxyProvider has
perforamed successfully
System.out.println("------ failing over read request"); <---- use
the log way instead
return getRetryAction(RetryAction.RETRY, retries, failovers);
{code}
was (Author: linyiqun):
Hi [~hanishakoneru], just take a quick review, one comment from me: I think we
can make {{ROLE_CHECK_INTERVAL}} configurable. In some scenarios, admins maybe
want to let cache leader id be more-updated.
> Serve read requests directly from RocksDB
> -----------------------------------------
>
> Key: HDDS-1175
> URL: https://issues.apache.org/jira/browse/HDDS-1175
> Project: Hadoop Distributed Data Store
> Issue Type: Sub-task
> Reporter: Hanisha Koneru
> Assignee: Hanisha Koneru
> Priority: Major
> Attachments: HDDS-1175.001.patch
>
>
> We can directly server read requests from the OM's RocksDB instead of going
> through the Ratis server. OM should first check its role and only if it is
> the leader can it server read requests.
> There can be a scenario where an OM can lose its Leader status but not know
> about the new election in the ring. This OM could server stale reads for the
> duration of the heartbeat timeout but this should be acceptable (similar to
> how Standby Namenode could possibly server stale reads till it figures out
> the new status).
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