MONITOR
MONITOR
- Available since:
- 1.0.0
- Time complexity:
- ACL categories:
-
@admin
,@slow
,@dangerous
,
MONITOR
is a debugging command that streams back every command processed by
the Redis server.
It can help in understanding what is happening to the database.
This command can both be used via redis-cli
and via telnet
.
The ability to see all the requests processed by the server is useful in order to spot bugs in an application both when using Redis as a database and as a distributed caching system.
$ redis-cli monitor
1339518083.107412 [0 127.0.0.1:60866] "keys" "*"
1339518087.877697 [0 127.0.0.1:60866] "dbsize"
1339518090.420270 [0 127.0.0.1:60866] "set" "x" "6"
1339518096.506257 [0 127.0.0.1:60866] "get" "x"
1339518099.363765 [0 127.0.0.1:60866] "eval" "return redis.call('set','x','7')" "0"
1339518100.363799 [0 lua] "set" "x" "7"
1339518100.544926 [0 127.0.0.1:60866] "del" "x"
Use SIGINT
(Ctrl-C) to stop a MONITOR
stream running via redis-cli
.
$ telnet localhost 6379
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
MONITOR
+OK
+1339518083.107412 [0 127.0.0.1:60866] "keys" "*"
+1339518087.877697 [0 127.0.0.1:60866] "dbsize"
+1339518090.420270 [0 127.0.0.1:60866] "set" "x" "6"
+1339518096.506257 [0 127.0.0.1:60866] "get" "x"
+1339518099.363765 [0 127.0.0.1:60866] "del" "x"
+1339518100.544926 [0 127.0.0.1:60866] "get" "x"
QUIT
+OK
Connection closed by foreign host.
Manually issue the QUIT
or RESET
commands to stop a MONITOR
stream running
via telnet
.
Commands not logged by MONITOR
Because of security concerns, no administrative commands are logged
by MONITOR
's output and sensitive data is redacted in the command AUTH
.
Furthermore, the command QUIT
is also not logged.
Cost of running MONITOR
Because MONITOR
streams back all commands, its use comes at a cost.
The following (totally unscientific) benchmark numbers illustrate what the cost
of running MONITOR
can be.
Benchmark result without MONITOR
running:
$ src/redis-benchmark -c 10 -n 100000 -q
PING_INLINE: 101936.80 requests per second
PING_BULK: 102880.66 requests per second
SET: 95419.85 requests per second
GET: 104275.29 requests per second
INCR: 93283.58 requests per second
Benchmark result with MONITOR
running (redis-cli monitor > /dev/null
):
$ src/redis-benchmark -c 10 -n 100000 -q
PING_INLINE: 58479.53 requests per second
PING_BULK: 59136.61 requests per second
SET: 41823.50 requests per second
GET: 45330.91 requests per second
INCR: 41771.09 requests per second
In this particular case, running a single MONITOR
client can reduce the
throughput by more than 50%.
Running more MONITOR
clients will reduce throughput even more.
Behavior change history
>= 6.0.0
:AUTH
excluded from the command's output.>= 6.2.0
: "RESET
can be called to exit monitor mode.>= 6.2.4
: "AUTH
,HELLO
,EVAL
,EVAL_RO
,EVALSHA
andEVALSHA_RO
included in the command's output.