How Hyperledger Fabric handle the Concurrent of “invoke” of the same Key-Value pair of chaincode?

Question

For example, two applications are connecting one chaincode, if the action to request "invoke" of the same Key-Value pair of chaincode almost at the same time, what will happen?

If it is a nightmare for Hyperledger Fabric, how can we handle on it? on side of Hyperledger core.yaml setting? or side of chaincode design?

Answer 1

The steps are :

1. The client sends transactions to Endorsers.
2. Endorsers execute the transaction, generating world state key/value changesets, which are called the Read/Write Set. Endorsers return result to client.
3. Client receives responses from all and compares result and R/W Set against endorsement policy.
4. Client forwards successful endorsement to ordering service, which creates blocks from a set of transactions.
5. Ordering service forwards complete block to all committers
6. Each committer applies the transactions' R/W Sets in order, updating each read key's version as it goes along . While committing each set, it performs a check on each key's version in the read set such that the key version must not be less than the current version number.