MONITOR(3valkey)

📦
version 9.0.6 · 2 versions
, in fedora 44

🌸 MONITOR(3valkey) — the valkey command manual, bestie edition 🌸

okay so this is the manual page for MONITOR from the Valkey Command Manual. yes it's a real page, yes it's iconic, let's get into it 💅

✨ NAME ✨

monitor — Listens for all requests received by the server in real-time.

🦋 SYNOPSIS 🦋

MONITOR

💖 DESCRIPTION 💖

okay so MONITOR is a debugging command that streams back every single command processed by the Valkey server. it's giving surveillance but make it helpful 💀 it can help in understanding what is happening to the database. and the best part? this command can both be used via valkey-cli and via telnet. versatile queen 👑

the ability to see all the requests processed by the server is useful in order to spot bugs in an application both when using Valkey as a database and as a distributed caching system. literally your bug-hunting bestie 🐛🔍

$ valkey-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 server.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 valkey-cli. know when to log off, periodt ✋

$ 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 valkey-quit(7) QUIT or valkey-reset(7) RESET commands to stop a MONITOR stream running via telnet. manual exit, no drama 🎀

🚫 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 valkey-auth(7) AUTH. privacy first, always 🫶

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. ngl bestie, it's not cheap 😭

Benchmark result without MONITOR running:

$ src/valkey-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 (valkey-cli monitor > /dev/null):

$ src/valkey-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. it's giving "one more won't hurt" and then it absolutely does 🙈

Note that, - valkey-auth(7) AUTH is excluded from the command's output. - valkey-reset(7) RESET can be called to exit monitor mode. - AUTH, valkey-hello(7) HELLO, valkey-eval(7) EVAL, valkey-eval_ro(7) EVAL_RO, valkey-evalsha(7) EVALSHA and valkey-evalsha_ro(7) EVALSHA_RO are included in the command's output.

🌈 REPLY 🌈

Non-standard return value. Dumps the received commands in an infinite flow. it literally never stops talking, main character energy fr fr 💜

👑 ACL CATEGORIES 👑

@admin @dangerous @slow

⭐ HISTORY ⭐

  • Available since: 1.0.0 — a legend since day one, no cap 🌟

🎀 SEE ALSO 🎀

and that's the whole page bestie 🫶 this was Valkey version 9.0.0, dated 2025-10-21 — go forth, monitor responsibly, and don't leave it running in prod, i'm literally begging 😭💖✨

📦 where this page comes from