詳解redis-cli 命令

2022-10-20 14:03:53

命令使用:

redis-cli [OPTIONS] [cmd [arg [arg ...]]]

選項說明:

  -h <hostname>      Server hostname (default: 127.0.0.1). ip地址
  -p <port>          Server port (default: 6379).　伺服器埠號
  -s <socket>        Server socket (overrides hostname and port).
  -a <password>      Password to use when connecting to the server.　密碼
  -u <uri>           Server URI.　url格式的地址
  -r <repeat>        Execute specified command N times.
  -i <interval>      When -r is used, waits <interval> seconds per command.
                     It is possible to specify sub-second times like -i 0.1.
  -n <db>            Database number.　指定資料庫
  -x                 Read last argument from STDIN.
  -d <delimiter>     Multi-bulk delimiter in for raw formatting (default: n).
  -c                 Enable cluster mode (follow -ASK and -MOVED redirections).
  --raw              Use raw formatting for replies (default when STDOUT is
                     not a tty).
  --no-raw           Force formatted output even when STDOUT is not a tty.
  --csv              Output in CSV format.
  --stat             Print rolling stats about server: mem, clients, ...　統計資料　連續輸出
  --latency          Enter a special mode continuously sampling latency.
                     If you use this mode in an interactive session it runs
                     forever displaying real-time stats. Otherwise if --raw or
                     --csv is specified, or if you redirect the output to a non
                     TTY, it samples the latency for 1 second (you can use
                     -i to change the interval), then produces a single output
                     and exits.　延時統計
  --latency-history  Like --latency but tracking latency changes over time.
                     Default time interval is 15 sec. Change it using -i.
  --latency-dist     Shows latency as a spectrum, requires xterm 256 colors.
                     Default time interval is 1 sec. Change it using -i.
  --lru-test <keys>  Simulate a cache workload with an 80-20 distribution.
  --replica          Simulate a replica showing commands received from the master.
  --rdb <filename>   Transfer an RDB dump from remote server to local file. 匯出rdb檔案
  --pipe             Transfer raw Redis protocol from stdin to server.
  管道模式
  --pipe-timeout <n> In --pipe mode, abort with error if after sending all data.
                     no reply is received within <n> seconds.
                     Default timeout: 30. Use 0 to wait forever.
                     管道超時
  --bigkeys          Sample Redis keys looking for big keys.
  --hotkeys          Sample Redis keys looking for hot keys.
                     only works when maxmemory-policy is *lfu.
  --scan             List all keys using the SCAN command.獲取伺服器所有的鍵
  --pattern <pat>    Useful with --scan to specify a SCAN pattern.
  正規表示式　用於scan命令中
  --intrinsic-latency <sec> Run a test to measure intrinsic system latency.
                     The test will run for the specified amount of seconds.
  --eval <file>      Send an EVAL command using the Lua script at <file>.
  --ldb              Used with --eval enable the Redis Lua debugger.
  --ldb-sync-mode    Like --ldb but uses the synchronous Lua debugger, in
                     this mode the server is blocked and script changes are
                     not rolled back from the server memory.
  --cluster <command> [args...] [opts...]
                     Cluster Manager command and arguments (see below).
  --verbose          Verbose mode.
  --no-auth-warning  Don't show warning message when using password on command
                     line interface.

注意：

-u 選項中url格式參考檔案https://www.iana.org/assignments/uri-schemes/prov/redis　

格式為：redis://user:secret@localhost:6379/0?foo=bar&qux=baz

舉例：

root@hylaz:~# redis-cli
127.0.0.1:6379> set name hylaz
OK
127.0.0.1:6379> quit
root@hylaz:~# redis-cli -h 127.0.0.1
127.0.0.1:6379> get name
"hylaz"
127.0.0.1:6379> select 6
127.0.0.1:6379[6]> 
 
root@hylaz:~# redis-cli -h 127.0.0.1 -p 6379 -n 2
127.0.0.1:6379[2]> get age

server中統計選項

root@hylaz:~# redis-cli --stat
------- data ------ --------------------- load -------------------- - child -
keys       mem      clients blocked requests            connections          
11         835.52K  1       0       12 (+0)             5           
11         835.52K  1       0       13 (+1)             5         
11         835.52K  1       0       14 (+1)             5           
11         835.52K  1       0       15 (+1)             5

列表中選項說明：

選項	含義
keys	server中key的數量
mem	鍵值對的總記憶體量
clients	當前連線的總clients數量
blocked	當前阻塞的使用者端數量
requests	伺服器請求總次數 (+1) 截止上次請求增加次數
connections	伺服器連線次數

使用info命令獲取伺服器的資訊

匯入rdb檔案　命令：redis-cli --rdb rdb.log

root@hylaz:~# redis-cli --rdb rdb.log
SYNC sent to master, writing 344 bytes to 'rdb.log'
Transfer finished with success.

該命令選項實現：

向server傳送SYNC命令，返回需要寫的總位元組數
從server讀取總位元組資料寫到指定檔案中

找出各種資料型別的最大鍵值對　

命令：redis-cli --big-keys

root@hylaz:~# redis-cli --bigkeys
 
# Scanning the entire keyspace to find biggest keys as well as
# average sizes per key type.  You can use -i 0.1 to sleep 0.1 sec
# per 100 SCAN commands (not usually needed).
 
[00.00%] Biggest string found so far 'name1' with 5 bytes
[00.00%] Biggest set    found so far 'myset' with 1 members
[00.00%] Biggest string found so far 'key' with 6 bytes
 
-------- summary -------
 
Sampled 13 keys in the keyspace!
Total key length in bytes is 52 (avg len 4.00)
 
Biggest string found 'key' has 6 bytes
Biggest    set found 'myset' has 1 members
 
12 strings with 33 bytes (92.31% of keys, avg size 2.75)
0 lists with 0 items (00.00% of keys, avg size 0.00)
1 sets with 1 members (07.69% of keys, avg size 1.00)
0 hashs with 0 fields (00.00% of keys, avg size 0.00)
0 zsets with 0 members (00.00% of keys, avg size 0.00)
0 streams with 0 entries (00.00% of keys, avg size 0.00)

該選項實現：通過使用scan命令遍歷server中的鍵值對，針對不同資料型別進行統計，

找出server中熱點key 命令：redis-cli --hotkeys

# Scanning the entire keyspace to find hot keys as well as
# average sizes per key type.  You can use -i 0.1 to sleep 0.1 sec
# per 100 SCAN commands (not usually needed).
 
[00.00%] Hot key 'dd' found so far with counter 4
[00.00%] Hot key 'myset' found so far with counter 5
[00.00%] Hot key 'a' found so far with counter 5
[00.00%] Hot key 'dds' found so far with counter 4
[71.43%] Hot key 'aa' found so far with counter 4
[71.43%] Hot key 'key' found so far with counter 4
 
-------- summary -------
 
Sampled 14 keys in the keyspace!
hot key found with counter: 5	keyname: myset
hot key found with counter: 5	keyname: a
hot key found with counter: 4	keyname: dd
hot key found with counter: 4	keyname: dds
hot key found with counter: 4	keyname: aa
hot key found with counter: 4	keyname: key

選項實現：

1. redis實現8種快取淘汰策略：

voltile-lru：從已設定過期時間的資料集（server.db[i].expires）中挑選最近最少使用的資料淘汰

volatile-ttl：從已設定過期時間的資料集（server.db[i].expires）中挑選將要過期的資料淘汰

volatile-random：從已設定過期時間的資料集（server.db[i].expires）中任意選擇資料淘汰

volatile-lfu: 從已設定過期時間的資料集驅逐使用頻率最少的鍵

allkeys-lru:從資料集（server.db[i].dict）中挑選最近最少使用的資料淘汰

allkeys-lfu: 從所有鍵中驅逐使用頻率最少的鍵

allkeys-random：從資料集（server.db[i].dict）中任意選擇資料淘汰

no-enviction（驅逐）：禁止驅逐資料當記憶體不足以容納新寫入資料時，新寫入操作會報錯

需要設定淘汰策略為lru或者lfu

2. 命令實現使用scan命令遍歷所有的鍵值對，針對每個鍵值對使用OBJECT freq 獲取該鍵值對的資訊