Pavel Yaskevich commented on CASSANDRA-9754:

bq. I'm actually only am using the key cache in the current implementation

I wanted to mention that purely from looking up key in the key cache 
perspective, I've assumed that index is only going to have key offsets in it, 
so we are on the same page. 

[~barnie] Is there any way you can run this through automated perf stress test? 
Since the size of the tree attached to the key is bigger than it was 
originally, I'm curious what is performance difference in conditions where rows 
are just barely big enough to be indexed and there are a lot of keys.

[~mkjellman] I understand that the test you are running is designed to check 
what is the performance like relative to the Birch tree itself, but is there 
there any chance you can disable key cache and generate some more keys (maybe 
~100k?) to see how changes to the column index are affecting read path top-down?

> 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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