Client Commands

Client commands for managing connections, debugging, and controlling client behavior.

Commands

Command	Syntax	Description
CLIENT SETNAME	CLIENT SETNAME name	Set connection name
CLIENT GETNAME	CLIENT GETNAME	Get connection name
CLIENT LIST	CLIENT LIST	List all connected clients
CLIENT ID	CLIENT ID	Get current connection ID
CLIENT INFO	CLIENT INFO	Get current connection info
CLIENT KILL	CLIENT KILL ID id	Kill a client connection
CLIENT PAUSE	CLIENT PAUSE ms	Pause all clients
CLIENT UNPAUSE	CLIENT UNPAUSE	Resume paused clients

Examples

Connection Naming

Set a meaningful name for debugging:

127.0.0.1:6379> CLIENT SETNAME worker-1
OK

127.0.0.1:6379> CLIENT GETNAME
"worker-1"

Get Connection ID

127.0.0.1:6379> CLIENT ID
(integer) 42

Current Connection Info

127.0.0.1:6379> CLIENT INFO
id=42 addr=127.0.0.1:52341 name=worker-1 db=0 cmd=client

List All Clients

127.0.0.1:6379> CLIENT LIST
id=1 addr=127.0.0.1:52340 name=admin db=0 cmd=client
id=42 addr=127.0.0.1:52341 name=worker-1 db=0 cmd=get
id=43 addr=127.0.0.1:52342 name=worker-2 db=0 cmd=blpop
id=44 addr=127.0.0.1:52343 name= db=1 cmd=set

Each line shows:

• id - Unique connection ID
• addr - Client IP and port
• name - Client name (if set)
• db - Selected database
• cmd - Last command executed

Kill a Client

# Find the client
127.0.0.1:6379> CLIENT LIST
id=99 addr=192.168.1.100:12345 name=rogue-client db=0 cmd=keys

# Kill by ID
127.0.0.1:6379> CLIENT KILL ID 99
OK

Pause All Clients

Temporarily pause all client operations (useful for maintenance):

# Pause for 5 seconds
127.0.0.1:6379> CLIENT PAUSE 5000
OK

# All other clients block on commands...

# Or resume early
127.0.0.1:6379> CLIENT UNPAUSE
OK

Practical Examples

Identify Slow Clients

# List clients to see what they're doing
127.0.0.1:6379> CLIENT LIST
id=1 addr=127.0.0.1:52340 name=web-1 cmd=get
id=2 addr=127.0.0.1:52341 name=web-2 cmd=get
id=3 addr=127.0.0.1:52342 name=batch-job cmd=keys  # Slow KEYS command!

Connection Debugging

# Set descriptive name on connect
CLIENT SETNAME "api-server-pod-abc123"

# Later, in monitoring:
CLIENT LIST
# Can identify which pod/service each connection belongs to

Graceful Maintenance

# 1. Pause writes during backup
CLIENT PAUSE 10000

# 2. Perform backup
# ... backup operations ...

# 3. Resume
CLIENT UNPAUSE

Kill Misbehaving Clients

# Find clients doing expensive operations
127.0.0.1:6379> CLIENT LIST
id=50 addr=10.0.0.5:43210 name= db=0 cmd=keys  # KEYS * is bad!

# Terminate the connection
127.0.0.1:6379> CLIENT KILL ID 50
OK

Client Info Fields

Field	Description
id	Unique client connection ID
addr	Client address (IP:port)
name	Client name from CLIENT SETNAME
db	Currently selected database (0-15)
cmd	Last command executed

Use Cases

Application Monitoring

# Each app instance names itself
CLIENT SETNAME "app-instance-${HOSTNAME}"

# Ops team can see all connections
CLIENT LIST

Connection Limits

# Check how many clients connected
CLIENT LIST
# Count lines to see total connections

# Kill oldest/idle connections if needed
CLIENT KILL ID <oldest_id>

Debugging Connection Issues

# Which database is this connection using?
CLIENT INFO
# Shows: db=3

# What was the last command?
CLIENT INFO
# Shows: cmd=hgetall

Blue-Green Deployments

# During deployment:
# 1. Pause old clients
CLIENT PAUSE 30000

# 2. Deploy new version

# 3. Resume (or let timeout expire)
CLIENT UNPAUSE

Important Notes

Server Mode Only

CLIENT commands are only available in server mode - they manage TCP connections which don’t exist in embedded library mode.

CLIENT PAUSE Behavior

• All clients (except the one issuing PAUSE) block
• Read and write commands are paused
• Pub/Sub messages are still delivered
• Timeout in milliseconds

Connection Naming

• Names have no spaces or special characters
• Empty string clears the name
• Names are for debugging only, no security implications

Killing Connections

• CLIENT KILL immediately closes the TCP connection
• Client will need to reconnect
• Use for misbehaving clients or maintenance