A Redis transaction failed before execution due to syntax errors or command validation issues. Fix by validating all commands in the MULTI block before calling EXEC.
This error occurs when Redis detects a problem with one or more commands in a MULTI/EXEC transaction block during the queuing phase, before EXEC is called. Redis aborts the entire transaction to prevent execution of invalid commands. This is a safety mechanism that occurs at parse time, catching syntax errors, invalid command names, wrong argument counts, and critical conditions like out-of-memory.
Review each command in your MULTI/EXEC block for syntax errors. Check that:
- Command names are spelled correctly
- Argument counts match the command specification
- Data types are appropriate for the operation
Example of invalid command:
MULTI
INCRBY mykey # Missing argument - causes EXECABORT
EXECBefore wrapping commands in a transaction, run each command individually in redis-cli to ensure they work:
INCRBY mykey 1
SET mystring "value"
LPUSH mylist itemIf any command fails, fix it before adding to a MULTI/EXEC block.
Ensure you're passing the correct number of arguments. Use redis-cli HELP to verify:
127.0.0.1:6379> COMMAND INFO INCRBYCommon mistakes:
- INCRBY requires 2 arguments: key and increment
- SETEX requires 3 arguments: key, seconds, value
- LPUSH requires at least 2 arguments: key and value(s)
If using WATCH, monitor for modifications:
WATCH mykey
MULTI
SET mykey newvalue
EXEC # Returns null if mykey was modifiedIf EXEC returns null, retry the transaction with exponential backoff.
Use redis-cli monitor to observe commands in real-time:
redis-cli monitorThis shows all commands received by Redis and helps identify malformed requests.
If syntax is correct but EXECABORT still occurs, verify Redis server resources:
INFO memoryIf used_memory is near maxmemory, free up space by deleting unnecessary keys or increasing Redis memory limits.
Redis distinguishes between two types of transaction errors: (1) Syntactical errors caught before EXEC - these trigger EXECABORT, and (2) runtime errors caught after EXEC - these do not abort but return error replies for individual commands. Importantly, Redis transactions provide atomicity but NOT rollback capability. Commands that fail after EXEC has been called do not automatically undo previous commands in the transaction. DISCARD can be used to abort a transaction and reset the connection state. In Redis Cluster, EXECABORT can also occur if cluster slot migration happens during a transaction - if this occurs repeatedly, restart your client application to refresh cluster slot mappings.
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