DEBUG

DEBUG groups subcommands for diagnosing a server. Some of them can stop the server or replace its data, so DEBUG is refused unless the enable-debug-command setting allows it:

enable-debug-command	Who can run DEBUG
no (default)	Nobody.
local	Clients connected over a loopback address (127.0.0.1, ::1).
yes	Any client whose ACL user may run it.

The setting can only be changed in the config file, followed by a restart. Otherwise every DEBUG call fails with:

ERR DEBUG command not allowed. If the enable-debug-command option is set to "local", you can run it from a local connection, otherwise you need to set this option in the configuration file, and then restart the server.

DEBUG cannot be run from a script. DEBUG HELP lists the subcommands.

Subcommands

Subcommand	What it does	Reply
SLEEP seconds	Stop the whole server for seconds (fractions allowed): no command runs meanwhile, and in a cluster the node stops talking to other nodes too. Useful to test client timeouts and failover.	OK
OBJECT key	One line about a key. Its encoding (as OBJECT ENCODING gives it) and lru_seconds_idle (seconds since last access) are meaningful; the other fields are fixed placeholders. ERR no such key if it does not exist.	Simple string
POPULATE count [prefix] [size]	Create string keys prefix:0 to prefix:<count-1> (prefix key by default) holding value:<n>, padded with zero bytes or cut to size bytes when size is given. Existing keys are left as they are. For diagnostics only: these keys are not written to the AOF or sent to replicas.	OK
DIGEST	A 40-hex-digit digest of every database’s keys, types, values and expiry. Two servers with the same data give the same digest, which makes it easy to check a replica or a restore. All zeros when there are no keys.	Simple string
DIGEST-VALUE key [key ...]	The digest of each key’s value, all zeros for a missing key.	Array of simple strings
LOG message	Write message to the server log, for marking a point in the log during tests.	OK
RELOAD [NOSAVE]	Write a snapshot (unless NOSAVE). The data in memory is not reloaded from it.	OK
LOADAOF	Write the AOF to disk, empty the data set, and load it again from the AOF. Needs appendonly yes.	OK
RESTART [milliseconds]	Shut down as SHUTDOWN does, rewrite the config file as CONFIG REWRITE does, and start the server again after the delay with the same arguments. No reply.	None
SET-ACTIVE-EXPIRE 0|1	Turn the background removal of expired keys off (0) or on. With it off, expired keys are removed only when a command finds them.	OK
CHANGE-REPL-ID	Accepted, with no effect.	OK
PAUSE-CRON 0|1	Accepted, with no effect.	OK
CLIENT-EXTRA-MEMORY bytes	Count that many more bytes in this connection’s tot-mem and toward maxmemory-clients, from the end of the command. Useful to check how client eviction behaves.	OK

DEBUG HELP lists further diagnostic subcommands, including some for clusters.

Errors: ERR unknown DEBUG subcommand '<NAME>'. Try DEBUG HELP. for an unknown subcommand, and the usual argument errors.

Examples

127.0.0.1:6379> DEBUG DIGEST
0000000000000000000000000000000000000000
127.0.0.1:6379> DEBUG POPULATE 3
OK
127.0.0.1:6379> DEBUG DIGEST-VALUE nosuchkey
1) 0000000000000000000000000000000000000000
127.0.0.1:6379> DEBUG SLEEP 0.5
OK

In HotKV Cloud, the CLI tab of the panel does not run DEBUG.

Compatibility

Redis 7 and Valkey 8 gate DEBUG with the same setting and messages, and have many more subcommands. HotKV has the subcommands that operators rely on. Differences in the ones it has: RELOAD saves but does not reload, OBJECT reports placeholder values for fields other than the encoding and idle time, and CHANGE-REPL-ID does nothing.

See also

OBJECT ENCODING, MEMORY USAGE, SHUTDOWN, configuration reference