Michael Kjellman commented on CASSANDRA-9754:

All of the threads that were responsible for generating load in the control 
cluster for the two large partition read and write workloads had died because 
the cluster became so unstable. As soon as I just restarted the stress load 60% 
of the instances in the cluster OOMed within 2 minutes of restarting the load. 

At this point I don't think I can drive any more data into the partitions with 
the old code and I'm going to declare defeat and say that 17GB as the absolute 
max partition size possible with the old/previous/current index implementation 
(given the JVM parameters as I detailed in the test description above).

I'm going to leave the load at the current read and write rates in the two 
Birch clusters until things explode to see the theoretical max partition size 
possible with the Birch implementation today. After that I'll wipe the clusters 
and restart the same load at 2x the read and write rates to see how things go 
with that configuration.

> Make index info heap friendly for large CQL partitions
> ------------------------------------------------------
>                 Key: CASSANDRA-9754
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-9754
>             Project: Cassandra
>          Issue Type: Improvement
>            Reporter: sankalp kohli
>            Assignee: Michael Kjellman
>            Priority: Minor
>             Fix For: 4.x
>         Attachments: gc_collection_times_with_birch.png, 
> gc_collection_times_without_birch.png, gc_counts_with_birch.png, 
> gc_counts_without_birch.png, 
> perf_cluster_1_with_birch_read_latency_and_counts.png, 
> perf_cluster_1_with_birch_write_latency_and_counts.png, 
> perf_cluster_2_with_birch_read_latency_and_counts.png, 
> perf_cluster_2_with_birch_write_latency_and_counts.png, 
> perf_cluster_3_without_birch_read_latency_and_counts.png, 
> perf_cluster_3_without_birch_write_latency_and_counts.png
>  Looking at a heap dump of 2.0 cluster, I found that majority of the objects 
> are IndexInfo and its ByteBuffers. This is specially bad in endpoints with 
> large CQL partitions. If a CQL partition is say 6,4GB, it will have 100K 
> IndexInfo objects and 200K ByteBuffers. This will create a lot of churn for 
> GC. Can this be improved by not creating so many objects?

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