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Troubleshooting & Problem Resolution Flashcards

7 cards from real CBDH practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

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  1. Committing a chaincode definition fails with 'chaincode definition not agreed to by this org'. Which command helps diagnose it?

    Answer: peer lifecycle chaincode checkcommitreadiness

    checkcommitreadiness shows which organizations have approved the definition with matching parameters.

  2. An approval succeeds, but the chaincode never starts because the package ID used does not match the installed package. How do you retrieve the correct ID?

    Answer: peer lifecycle chaincode queryinstalled

    queryinstalled lists installed packages with their label-hash package IDs.

  3. Committing an updated chaincode fails: 'requested sequence is 2, but new definition must be sequence 3'. What is the fix?

    Answer: Approve and commit using --sequence 3

    Each definition change must use the next sequence number after the currently committed one.

  4. A transaction using a range query is invalidated with PHANTOM_READ_CONFLICT. What does this indicate?

    Answer: Keys within the queried range changed between simulation and commit

    Range query results are re-validated at commit time, and added or removed keys cause a phantom read conflict.

  5. A peer reports 'private data matching public hash version is not available'. What should you investigate?

    Answer: Collection membership, gossip connectivity, and private data reconciliation on that peer

    The peer has the public hash but has not received the private payload, usually due to collection or gossip problems.

  6. A chaincode calling GetQueryResult fails on a network whose peers use LevelDB. Why?

    Answer: Rich (JSON selector) queries require CouchDB as the state database

    Only CouchDB supports JSON rich queries, while LevelDB supports key and range queries.

  7. With chaincode-as-a-service, the peer logs connection refused when launching the chaincode. What is the most likely cause?

    Answer: The address in connection.json is wrong or the chaincode server is not listening

    The peer dials the address in the package's connection.json, so a wrong address or a stopped server causes refusal.

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Sources & references

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  1. blockchaintrainingalliance.com — Test delivery, passing score, score release, test dates, fees, exam format, time limit · verified Oct 2026