Details
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Bug
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Status: Resolved
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Normal
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Resolution: Fixed
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None
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Correctness - Unrecoverable Corruption / Loss
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Critical
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Normal
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Fuzz Test
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All
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None
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Description
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.
Attachments
Attachments
Issue Links
- relates to
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CASSANDRA-20192 Use non-reversed byte-comparable values for SAI on-disk indexes on reversed clustering keys
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- Open
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- links to
