jankotek / jankotek/mapdb

Map reduce support

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Dominant language
Java
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Description

I am currently thinking about implementing map reduce with MapDB maps in my application. CouchDB has an approach where intermediate reduce results get stored in b-tree nodes for faster computations after b-tree changes (only nodes with changed children need to be recomputed). That might also be possible with MapDB, when DirNodes could have additional persistent properties.
Would be interesting to have such a map/reduce functionality built right into the MapDB core.

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reviewing MapDB core's map implementation and the role of DirNodes in persistent storage. Compare the proposed CouchDB-style intermediate reduce results with MapDB's current design, then define the API and persistence behavior needed for incremental recomputation after tree changes.

Written by the indexing model from the issue text.

Assessment

Tech stack
java
Domain
databases
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
20/100

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