RocksDB iterator seek until last matching prefix

Question

How do I tell a RocksDB iterator to seek until the last matching prefix?

In Clojure using the RocksDB Java API:

(import '(org.rocksdb RocksDB Options ReadOptions RocksIterator Slice))
(let [opts (-> (ReadOptions.)
               (.setPrefixSameAsStart true)
               (.setTotalOrderSeek true))
      iter (.newIterator db)]
  (.seek iter (.getBytes ("some-prefix:"))
  (.key iter))
=> "not-matching-prefix"

Do I have to manually check if the next key matches the prefix? This seems suboptimal because I have to stream in the whole key to check it, when RocksDB could eject early.

score 4 · Answer 1 · answered Mar 07 '20 at 16:19

4

Yes, you can provide RocksDB the upper bound to optimize it - by using setIterateUpperBound in ReadOptions.

answered Mar 07 '20 at 16:19

rmcv

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RocksDB iterator seek until last matching prefix

1 Answers1