Status

Current state: Under Discussion

Discussion thread: here [Change the link from the KIP proposal email archive to your own email thread]

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Motivation

Provide an implementation of the Query interface, introduced in KIP-796: Interactive Query v2 , to support reverseRange and reverseAll

Proposed Changes

The ReverseRangeQuery  class will be used for both reverseRange and reverseAll queries. A reverseAll is performed when no lower and no upper bound is specified. A reverseRange query retrieves a set of keys, specified using an upper and/or lower bound, from the underlying KV store. A reverseAll, on the other hand, retrieves all keys contained in the KV store.

Compatibility, Deprecation, and Migration Plan

• Because we have already have RangeQuery, so we can achieve the ReverseRangeQuery following RangeQuery.
• Since nothing is deprecated in this KIP, users have no need to migrate unless they want to.

Rejected Alternatives

Initially, we want to reuse the code in RangeQuery , but in the end, we find reuse the code will lead some problem, so we rewrite some methods to achieve ReverseRangeQuery .