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https://issues.apache.org/jira/browse/CASSANDRA-11206?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15243640#comment-15243640
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T Jake Luciani commented on CASSANDRA-11206:
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Looks like you still have ColumnIndex but it's been refactored into
RowIndexWriter.
I think RowIndexWriter should be moved to and replace ColumnIndex since there is
no need to move it.
In BTW.addIndexBlock() the indexOffsets[0] is always 0 since its always skipped
on the null case and columnIndexCount is incremented.
It looks like it was intentional but it's not easy to understand. I think it
works out because indexSamplesSerializedSize is 0 anyway.
Please explain in RowIndexEntry.create why you are returning each of the types.
It's not clear why indexSamples == null && columnIndexRow > 1 is significant.
It seems like you don't need indexOffsets once you reach
column_index_cache_size_in_kb
it's only used for the non-indexes. Does that mean the offsets aren't being
written to the index properly?
In the RIE example they are all appended to the end.
> Support large partitions on the 3.0 sstable format
> --------------------------------------------------
>
> Key: CASSANDRA-11206
> URL: https://issues.apache.org/jira/browse/CASSANDRA-11206
> Project: Cassandra
> Issue Type: Improvement
> Reporter: Jonathan Ellis
> Assignee: Robert Stupp
> Fix For: 3.x
>
> Attachments: 11206-gc.png, trunk-gc.png
>
>
> Cassandra saves a sample of IndexInfo objects that store the offset within
> each partition of every 64KB (by default) range of rows. To find a row, we
> binary search this sample, then scan the partition of the appropriate range.
> The problem is that this scales poorly as partitions grow: on a cache miss,
> we deserialize the entire set of IndexInfo, which both creates a lot of GC
> overhead (as noted in CASSANDRA-9754) but is also non-negligible i/o activity
> (relative to reading a single 64KB row range) as partitions get truly large.
> We introduced an "offset map" in CASSANDRA-10314 that allows us to perform
> the IndexInfo bsearch while only deserializing IndexInfo that we need to
> compare against, i.e. log(N) deserializations.
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