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https://issues.apache.org/jira/browse/CASSANDRA-12268?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15543085#comment-15543085
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Carl Yeksigian commented on CASSANDRA-12268:
--------------------------------------------
Just realized that there is an issue with using the same path for the regular
update and during build, in that we can break apart batches and not provide the
same semantics as we currently do.
I've just added a boolean to determine whether or not to return more than one
mutation. I'll kick off new CI runs.
> Make MV Index creation robust for wide referent rows
> ----------------------------------------------------
>
> Key: CASSANDRA-12268
> URL: https://issues.apache.org/jira/browse/CASSANDRA-12268
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Jonathan Shook
> Assignee: Carl Yeksigian
> Fix For: 3.0.x, 3.x
>
> Attachments: 12268.py
>
>
> When creating an index for a materialized view for extant data, heap pressure
> is very dependent on the cardinality of of rows associated with each index
> value. With the way that per-index value rows are created within the index,
> this can cause unbounded heap pressure, which can cause OOM. This appears to
> be a side-effect of how each index row is applied atomically as with batches.
> The commit logs can accumulate enough during the process to prevent the node
> from being restarted. Given that this occurs during global index creation,
> this can happen on multiple nodes, making stable recovery of a node set
> difficult, as co-replicas become unavailable to assist in back-filling data
> from commitlogs.
> While it is understandable that you want to avoid having relatively wide rows
> even in materialized views, this represents a particularly difficult
> scenario for triage.
> The basic recommendation for improving this is to sub-group the index
> creation into smaller chunks internally, providing a maximal bound against
> the heap pressure when it is needed.
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