redis Errors

39 error patterns

Redis operation on wrong data type

Redis.*WRONGTYPE Operation against a key holding the wrong kind of value

•Check key type with TYPE command before operating
•Delete and recreate key if type needs to change

Redis cluster is down

Redis.*CLUSTERDOWN.*The cluster is down

•Check cluster health: redis-cli --cluster check <host>:<port>
•Verify all master nodes have sufficient slots assigned

Redis cluster CROSSSLOT error

Redis.*ERR Error running script.*CROSSSLOT Keys in request don't hash to the same slot

•Use hash tags to force keys to same slot: {user:1}:profile, {user:1}:settings
•Split multi-key operation into per-slot operations

Redis still loading dataset into memory

Redis.*LOADING Redis is loading the dataset in memory

•Wait for Redis to finish loading (check with INFO persistence)
•Reduce dataset size or increase memory for faster load

Redis out of memory - maxmemory exceeded

Redis.*OOM command not allowed when used memory > 'maxmemory'

•Increase maxmemory in redis.conf
•Set eviction policy: maxmemory-policy allkeys-lru

Redis cluster slot already being migrated

Redis.*ERR Slot.*is already busy

•Complete or cancel the in-progress migration first
•Use CLUSTER SETSLOT <slot> STABLE on both nodes to reset

Redis JSON module command not available

Redis.*ERR unknown command.*JSON\.

•Load RedisJSON module: loadmodule /path/to/rejson.so
•Upgrade to Redis Stack which includes JSON module

Redis script not cached for EVALSHA

Redis.*NOSCRIPT No matching script.*EVALSHA

•Use EVAL instead of EVALSHA for the first call
•Catch NOSCRIPT error and fall back to EVAL with full script

Redis write command sent to replica

Redis.*READONLY.*can't write against a read only replica

•Connect to the master node for write operations
•Use Redis client library with master/replica awareness

Redis Stream XADD MAXLEN invalid value

Redis.*ERR XADD.*MAXLEN.*must be positive

•Use a positive integer for MAXLEN: XADD stream MAXLEN 1000 * field value
•Use ~ for approximate trimming: MAXLEN ~ 1000

Redis Stream consumer group doesn't exist

Redis.*ERR XREADGROUP.*NOGROUP.*No such.*consumer group

•Create consumer group first: XGROUP CREATE stream group_name $ MKSTREAM
•Use 0 instead of $ for group start ID to read from beginning

Redis invalid expire time

Redis.*ERR invalid expire time.*SETEX

•Ensure expire time is a positive integer (seconds for SETEX)
•Use PSETEX for millisecond precision

Redis transaction aborted due to error in MULTI block

Redis.*EXECABORT.*Transaction discarded because of previous errors

•Fix the command that caused the error within the MULTI block
•Check all commands are valid before EXEC

Redis busy with long-running script

Redis.*BUSY.*Redis is busy running a script

•Optimize the Lua script to run faster
•Use SCRIPT KILL to terminate a read-only script

Redis Bloom filter doesn't exist

Redis.*ERR.*BF\.ADD.*not an existing.*Bloom Filter

•Create Bloom filter first: BF.RESERVE key error_rate capacity
•Use BF.ADD which auto-creates with default parameters

Redis Top-K structure not initialized

Redis.*ERR.*TOPK\.ADD.*requires.*Top-K.*structure

•Initialize with TOPK.RESERVE key topk width depth decay
•Load Redis probabilistic data structures module

Redis cluster MOVED redirect

Redis.*MOVED (\d+) .*:.*

•Use a cluster-aware client that handles MOVED automatically
•Update slot-to-node mapping: CLUSTER SLOTS or CLUSTER SHARDS

Redis cluster ASK redirect during migration

Redis.*ASK (\d+) .*:.*

•Send ASKING command to target node before retrying the command
•Use cluster-aware client that handles ASK automatically

Redis Count-Min Sketch initialization error

Redis.*ERR.*CMS\.INITBYDIM.*not a valid.*Count-Min Sketch

•Initialize with CMS.INITBYDIM key width depth
•Or use CMS.INITBYPROB key error probability

Redis WRONGTYPE operation on wrong data structure

WRONGTYPE Operation against a key holding the wrong kind of value

•Check key's type with TYPE command before operating on it
•Delete the key and recreate with correct type if data structure changed

Redis connection refused

ECONNREFUSED.*6379|Redis.*connection.*refused|connect ECONNREFUSED

•Verify Redis server is running: redis-cli ping
•Check host and port in connection config (default: localhost:6379)

Redis max memory limit reached

OOM command not allowed.*maxmemory|maxmemory.*reached

•Configure an eviction policy: maxmemory-policy allkeys-lru
•Increase maxmemory in redis.conf or use CONFIG SET

Redis serialization error

ReplyError.*ERR.*serialize|circular.*JSON.*redis

•Serialize complex objects with JSON.stringify() before storing
•Check for circular references in objects before caching

Redis pub/sub subscriber mode command error

subscriber.*cannot.*command|Connection in subscriber mode

•Use separate Redis client instances for pub/sub and regular commands
•The subscriber client can only use SUBSCRIBE/UNSUBSCRIBE/PSUBSCRIBE after subscribing

Redis authentication failure

NOAUTH.*Authentication required|ERR.*AUTH.*failed|invalid password

•Pass password in connection config: { password: 'your-password' }
•For Redis 6+ ACLs, provide both username and password

Redis Cluster cross-slot key error

CROSSSLOT.*Keys.*different.*slot|MOVED.*cluster

•Use hash tags {prefix} in key names to ensure related keys map to same slot
•Don't use multi-key commands (MGET, MSET) across different slots

Redis transaction (MULTI/EXEC) error

EXECABORT.*Transaction.*error|MULTI.*EXEC.*failed

•Check all commands in the transaction are valid before EXEC
•Use WATCH for optimistic locking — transaction aborts if watched key changes

Redis server busy loading data

LOADING.*Redis.*loading.*dataset|BUSY.*background save

•Wait for Redis to finish loading the RDB/AOF file before connecting
•Implement connection retry with exponential backoff on LOADING error

Redis Lua script timeout

ERR.*Lua.*script.*timeout|BUSY.*script.*kill

•Optimize Lua scripts to avoid long-running operations
•Increase lua-time-limit config if the script legitimately needs more time

Redis Streams consumer group error

ERR.*stream.*not exist|XREAD.*timeout|consumer group.*not found

•Create the stream and consumer group before reading: XGROUP CREATE mystream grp $ MKSTREAM
•Handle NOGROUP error by auto-creating the group on first use

Redis client connection closed unexpectedly

AbortError.*connection.*closed|ClientClosedError|Socket.*closed

•Enable auto-reconnect in client config (reconnectStrategy in ioredis/node-redis)
•Handle 'error' and 'reconnecting' events on the client for graceful degradation

Redis background save failure

MISCONF.*BGSAVE.*error|Can't.*save.*background

•Check disk space — Redis needs free space for RDB snapshot writes
•Set stop-writes-on-bgsave-error no if persistence isn't critical

Redis max clients limit reached

ERR.*max.*clients.*reached|too many connections|maxclients

•Increase maxclients in redis.conf (default 10000)
•Use connection pooling in your application (e.g., generic-pool)

Redis invalid TTL/expire value

ERR.*invalid expire time|ERR.*timeout.*negative

•Ensure TTL is a positive integer (seconds for EXPIRE, milliseconds for PEXPIRE)
•Check that the value isn't NaN or undefined before passing to expire command

Redis EVALSHA script not in cache

NOSCRIPT.*No matching script|EVALSHA.*script not cached

•Fall back to EVAL with full script when EVALSHA returns NOSCRIPT
•Use SCRIPT LOAD on application startup to pre-cache scripts

Redis pub/sub message size issue

ERR.*Pub/Sub.*message.*too large|message.*exceeds.*limit

•Keep pub/sub messages small — send IDs/references, not full payloads
•Compress large messages before publishing (gzip/lz4)

Redis write to replica/slave error

READONLY.*cluster.*slave|READONLY.*replica.*not accept writes

•Direct write operations to the master node, not replicas
•Use a cluster-aware client that routes writes to master automatically

Redis SCAN cursor error

ERR.*scan.*cursor.*invalid|SCAN.*iteration.*error

•Always start SCAN with cursor 0 and continue until server returns 0
•Don't reuse cursors from previous SCAN iterations after reconnection

Redis Sentinel master discovery failure

ERR.*sentinel.*master.*not found|Sentinel.*failover.*error

•Verify sentinel nodes are running and can reach the Redis master
•Check master name in client config matches sentinel's monitored master name