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diff --git a/iredis/data/commands/monitor.md b/iredis/data/commands/monitor.md new file mode 100644 index 0000000..7900787 --- /dev/null +++ b/iredis/data/commands/monitor.md @@ -0,0 +1,93 @@ +`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] "del" "x" +1339518100.544926 [0 127.0.0.1:60866] "get" "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` command to stop a `MONITOR` stream running via +`telnet`. + +## Commands not logged by MONITOR + +Because of security concerns, all administrative commands are not logged by +`MONITOR`'s output. + +Furthermore, the following commands are also not logged: + +- `AUTH` +- `EXEC` +- `HELLO` +- `QUIT` + +## 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. + +@return + +**Non standard return value**, just dumps the received commands in an infinite +flow. + +@history + +- `>=6.0`: `AUTH` excluded from the command's output. |