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From "Aleksey Yeschenko (JIRA)" <>
Subject [jira] [Commented] (CASSANDRA-8038) A new config option to ignore column tombstones for RR or not
Date Wed, 08 Oct 2014 19:41:34 GMT


Aleksey Yeschenko commented on CASSANDRA-8038:

bq. Also, I understand read repair is the only reason why tombstones have to be kept in memory(both
for data and digest requests), and sent back to a coordinator(if it is a data request), though
only live columns are returned to a client. Am I right?

No, not right. Non-RR requests also return the tombstones, as they should, because there is
no guarantee that all the nodes participating in the requests have all the tombstones. That's
eventually consistent distributed deletes for you.

> A new config option to ignore column tombstones for RR or not
> -------------------------------------------------------------
>                 Key: CASSANDRA-8038
>                 URL:
>             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?

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