MULTI/EXEC compatibility: first runtime error aborts the whole transaction (Redis executes remaining commands)

[liunyl]

Summary

In Redis, runtime errors inside EXEC do not abort the transaction: every queued command executes and errors are reported per-command in the reply array (only queue-time errors abort). EloqKV's MultiExec aborts the entire engine transaction on the first runtime error.

Details

src/redis_service.cpp:2055 (RedisServiceImpl::MultiExec) — on a failed command the txn is aborted (:2345, "Error occurs in MultiExec, abort txn") and the client receives an aborted-EXEC result rather than an array containing the per-command error.

EloqKV's behavior is arguably better (real atomicity with rollback is the product's selling point), but it silently diverges from documented Redis semantics, which some clients/test suites rely on (e.g. wrong-type errors mid-transaction).

Suggested resolution

Decide and document the intended semantics:

• keep abort-on-error as an EloqKV feature → document prominently in compatibility docs (and docs/02-command-processing.md already records the divergence), or
• match Redis by executing remaining commands and embedding per-command errors, with rollback reserved for explicit BEGIN/ROLLBACK sessions.

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Found during the module-docs review (#492); see docs/02-command-processing.md.

🤖 Found with Claude Code