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https://issues.apache.org/jira/browse/CASSANDRA-15199?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17043936#comment-17043936
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Jeremy Justus commented on CASSANDRA-15199:
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Adding a future comment here, this NPE hole never got fixed by C* I don't think
but the reason for it was indeed Kong's lua behavior, a sort of variable
scoping issue that can be read here. [https://github.com/Kong/kong/pull/5564] ,
So it till could be handled more gracefully by C*.
> Cassandra throwing occasional NPE 3.11.x
> ----------------------------------------
>
> Key: CASSANDRA-15199
> URL: https://issues.apache.org/jira/browse/CASSANDRA-15199
> Project: Cassandra
> Issue Type: Bug
> Components: Messaging/Client
> Reporter: Jeremy Justus
> Priority: Normal
>
> Hey folks, decided to raise an official Jira(never done one of these before)
> about an issue we have found between Kong API Gateway leveraging Cassandra as
> our db.
> We run a C* cluster in 2 close DCs, 6 C* nodes total, 3 in each DC. Data
> replicated across all nodes. We have found C* sometimes throws NPEs based on
> the calls made by the lua-cassandra driver Kong
> leverages([https://github.com/thibaultcha/lua-cassandra]). Very specifically
> it seems to occur when attempting to do paging across multiple C* nodes. When
> persistently paging to a single C* node we can't reproduce NPEs in C*.
> The exact Error C* throws with its stack-trace can be seen here:
> [https://github.com/Kong/kong/issues/4194#issuecomment-497572751]
> And again when we tried to upgrade from 3.11.2 to 3.11.4 in hopes it was
> already resolved:
> [https://github.com/Kong/kong/issues/4194#issuecomment-497590235]
> Same error same line numbers, so code must be same in this portion.
>
> Sample of our C* Config:
> [https://github.com/Kong/kong/issues/4194#issuecomment-497595766]
> We discussed this in the ASF Slack flow as well:
> ASF Slack discussion
> ([https://the-asf.slack.com/archives/CJZLTM05A/p1559321422028200] )
> Some of the more important technical comments I saw people posting here:
> [https://github.com/Kong/kong/issues/4194#issuecomment-497858824]
>
> I am not a C* DBA so I don't have an exact repro for you other than stating
> what the client application was attempting to do(Paging across multiple C*
> nodes within a DC) when we could see the failures. Any Apache C* folk think
> they see the issue or could drop me C* JAR with extra debugging print
> statements I could run in dev to help feed you more info? Or if you see the
> problem and can one shot a fix so no more NPE and Cassandra responds
> appropriately to the client with some sort of error message around what was
> wrong that would be insightful.
>
> Thanks!
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