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https://issues.apache.org/jira/browse/CASSANDRA-20100?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17899915#comment-17899915
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Caleb Rackliffe commented on CASSANDRA-20100:
---------------------------------------------
Note that I've pushed the [trunk
patch|https://github.com/apache/cassandra/pull/3702] first. It has Harry tests
embedded, so it's good to know if those have issues before creating the 5.0
patch...
> Query construction is broken for SAI indexes on reversed types with
> fixed-length encodings
> ------------------------------------------------------------------------------------------
>
> Key: CASSANDRA-20100
> URL: https://issues.apache.org/jira/browse/CASSANDRA-20100
> Project: Cassandra
> Issue Type: Bug
> Components: Feature/2i Index, Feature/SAI
> Reporter: Caleb Rackliffe
> Assignee: Caleb Rackliffe
> Priority: Normal
> Fix For: 5.0.x, 5.x
>
> Time Spent: 10m
> Remaining Estimate: 0h
>
> SAI indexes values in byte-comparable form, both in the in-memory trie that
> sits alongside the Memtable, and in the on-disk SSTable-adjacent indexes. In
> most cases, this means literally using {{asComparableBytes()}} from the type
> of the indexed column. There are, however, a few types that use a custom
> byte-comparable form, namely {{inet}}, {{bigint}}, {{varint}}, and
> {{decimal}}, to make sure we're dealing with a fixed-length piece of data for
> the numeric (balanced tree) index.
> If we index one of these types as a reversed clustering key, however, we
> don't write terms as reversed comparable bytes, and this breaks some
> assumptions during query construction and post-filtering, where we generally
> assume that {{asComparableBytes()}} will reverse terms before they are
> indexed. We can make a short-term fix here without changing anything about
> the on-disk format by making sure we interpret these special types as being
> non-reversed (i.e. through the lens of their base types).
> In the longer term, it might make sense to standardize on indexing everything
> in a non-reversed fashion in the index itself, although this might push some
> complexity into post-filtering, where we are going to have to filter data
> coming out of the normal read path anyway.
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