[
https://issues.apache.org/jira/browse/CASSANDRA-8038?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14164148#comment-14164148
]
Takenori Sato commented on CASSANDRA-8038:
------------------------------------------
Thanks for your clarification! Now it seems I don't understand the
"reconciliation".
Let me refer to the comment of _StorageProxy.fetchRows_.
{quote}
1. Get the replica locations, sorted by response time according to the
snitch
2. Send a data request to the closest replica, and digest requests to
either
a) all the replicas, if read repair is enabled
b) the closest R-1 replicas, where R is the number required to satisfy
the ConsistencyLevel
3. Wait for a response from R replicas
4. If the digests (if any) match the data return the data
5. else carry out read repair by getting data from all the nodes.
{quote}
I understand _RowDigestResolver.resolve_ is called at 4, which checks if read
repair is required or not. And _RowDataResolver.resolve_ at 5, which does a
repair job.
I thought they(4 and 5) are called "read repair". But which part is called the
"reconciliation"?
> A new config option to ignore column tombstones for RR or not
> -------------------------------------------------------------
>
> Key: CASSANDRA-8038
> URL: https://issues.apache.org/jira/browse/CASSANDRA-8038
> Project: Cassandra
> Issue Type: New Feature
> Components: Core
> Reporter: Takenori Sato
> Fix For: 2.1.1
>
> Attachments: CASSANDRA-8038-v2.txt, CASSANDRA-8038-v3.txt,
> CASSANDRA-8038.txt
>
>
> CASSANDRA-6117 addressed the death of Cassandra by column tombstones, and
> whose fix was to raise an error when reading more tombstones than a
> threshold. I think it is an emergency action, rather than a fix.
> We have had this issue for long. So I wondered, in the first place, if it is
> really necessary to collect non-gc-able tombstones, which could cause
> concurrent mode failures, and OOM eventually?
> Actually, I was surprised by the fact that Cassandra takes them into
> consideration. Rather, I prefer to raise a threshold, and tell Cassandra to
> ignore tombstones for digest calculation of RR because a repair is running
> regularly.
> I guess there are some people like me, but not all. So what about adding a
> new configuration option if Cassandra ignores column tombstones for RR or not?
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
