# MONITOR

```json metadata
{
  "title": "MONITOR",
  "description": "Listens for all requests received by the server in real-time.",
  "categories": ["docs","develop","stack","oss","rs","rc","oss","kubernetes","clients"],
  "syntax_fmt": "MONITOR",
  "group": "server",
  "command_flags": ["admin","noscript","loading","stale"],
  "acl_categories": ["@admin","@slow","@dangerous"],
  "since": "1.0.0",
  "arity": 1,
  "tableOfContents": {"sections":[{"id":"commands-not-logged-by-monitor","title":"Commands not logged by MONITOR"},{"id":"cost-of-running-monitor","title":"Cost of running MONITOR"},{"id":"behavior-change-history","title":"Behavior change history"},{"id":"redis-enterprise-and-redis-cloud-compatibility","title":"Redis Enterprise and Redis Cloud compatibility"},{"id":"return-information","title":"Return information"}]}
}
```













`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`](https://redis.io/docs/latest/commands/quit) or [`RESET`](https://redis.io/docs/latest/commands/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`](https://redis.io/docs/latest/commands/auth).

Furthermore, the command [`QUIT`](https://redis.io/docs/latest/commands/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`](https://redis.io/docs/latest/commands/auth) excluded from the command's output.
*   `>= 6.2.0`: "[`RESET`](https://redis.io/docs/latest/commands/reset) can be called to exit monitor mode.
*   `>= 6.2.4`: "[`AUTH`](https://redis.io/docs/latest/commands/auth), [`HELLO`](https://redis.io/docs/latest/commands/hello), [`EVAL`](https://redis.io/docs/latest/commands/eval), [`EVAL_RO`](https://redis.io/docs/latest/commands/eval_ro), [`EVALSHA`](https://redis.io/docs/latest/commands/evalsha) and [`EVALSHA_RO`](https://redis.io/docs/latest/commands/evalsha_ro) included in the command's output.

## Redis Enterprise and Redis Cloud compatibility

| Redis<br />Enterprise | Redis<br />Cloud | <span style="min-width: 9em; display: table-cell">Notes</span> |
|:----------------------|:-----------------|:------|
| <span title="Supported">&#x2705; Standard</span><br /><span title="Supported"><nobr>&#x2705; Active-Active</nobr></span> | <span title="Supported">&#x2705; Standard</span><br /><span title="Supported"><nobr>&#x2705; Active-Active</nobr></span> |  |

## Return information

{{< multitabs id="monitor-return-info" 
    tab1="RESP2" 
    tab2="RESP3" >}}

**Non-standard return value**. Dumps the received commands in an infinite flow.

-tab-sep-

**Non-standard return value**. Dumps the received commands in an infinite flow.