【Redis】常用命令介绍

一、Redis常用基本命令

官方文档：https://redis.io/commands/

参考文档：http://redisdoc.com/

#可以使用help命令查看各redis命令用法
[root@Client-Ubuntu-1804-250:~]# redis-cli -a redis --no-auth-warning help
redis-cli 5.0.14
To get help about Redis commands type:
      "help @<group>" to get a list of commands in <group>
      "help <command>" for help on <command>
      "help <tab>" to get a list of possible help topics
      "quit" to exit

To set redis-cli preferences:
      ":set hints" enable online hints
      ":set nohints" disable online hints
Set your preferences in ~/.redisclirc

[root@Client-Ubuntu-1804-250:~]# redis-cli -a redis --no-auth-warning

#查看info命令帮助
127.0.0.1:6379> help info

  INFO [section]
  summary: Get information and statistics about the server
  since: 1.0.0
  group: server

#查看set命令帮助
127.0.0.1:6379> help set

  SET key value [expiration EX seconds|PX milliseconds] [NX|XX]
  summary: Set the string value of a key
  since: 1.0.0
  group: string

127.0.0.1:6379> 

1、INFO

查看当前节点运行状态

127.0.0.1:6379> help info

  INFO [section]
  summary: Get information and statistics about the server
  since: 1.0.0
  group: server

127.0.0.1:6379> info
# Server
redis_version:5.0.14
redis_git_sha1:00000000
redis_git_dirty:0
redis_build_id:5d32a2d9ed5f67d5
redis_mode:standalone
os:Linux 4.15.0-210-generic x86_64
arch_bits:64
multiplexing_api:epoll
atomicvar_api:atomic-builtin
gcc_version:7.5.0
process_id:6069
run_id:0e67fcd27ff6ae2589ff90ac2516bd52269f2965
tcp_port:6379
uptime_in_seconds:924
uptime_in_days:0
hz:10
configured_hz:10
lru_clock:5745912
executable:/app/redis/bin/redis-server
config_file:/app/redis/etc/redis_6379.conf

# Clients
connected_clients:1
client_recent_max_input_buffer:2
client_recent_max_output_buffer:0
blocked_clients:0

# Memory
used_memory:943496
used_memory_human:921.38K
used_memory_rss:7237632
used_memory_rss_human:6.90M
used_memory_peak:943496
used_memory_peak_human:921.38K
used_memory_peak_perc:100.11%
used_memory_overhead:898934
used_memory_startup:791488
used_memory_dataset:44562
used_memory_dataset_perc:29.32%
allocator_allocated:1129952
allocator_active:1409024
allocator_resident:14368768
total_system_memory:1006243840
total_system_memory_human:959.63M
used_memory_lua:37888
used_memory_lua_human:37.00K
used_memory_scripts:0
used_memory_scripts_human:0B
number_of_cached_scripts:0
maxmemory:0
maxmemory_human:0B
maxmemory_policy:noeviction
allocator_frag_ratio:1.25
allocator_frag_bytes:279072
allocator_rss_ratio:10.20
allocator_rss_bytes:12959744
rss_overhead_ratio:0.50
rss_overhead_bytes:-7131136
mem_fragmentation_ratio:8.03
mem_fragmentation_bytes:6336128
mem_not_counted_for_evict:1368
mem_replication_backlog:0
mem_clients_slaves:0
mem_clients_normal:49694
mem_aof_buffer:1368
mem_allocator:jemalloc-5.1.0
active_defrag_running:0
lazyfree_pending_objects:0

# Persistence
loading:0
rdb_changes_since_last_save:658
rdb_bgsave_in_progress:0
rdb_last_save_time:1683467492
rdb_last_bgsave_status:ok
rdb_last_bgsave_time_sec:0
rdb_current_bgsave_time_sec:-1
rdb_last_cow_size:233472
aof_enabled:1
aof_rewrite_in_progress:0
aof_rewrite_scheduled:0
aof_last_rewrite_time_sec:-1
aof_current_rewrite_time_sec:-1
aof_last_bgrewrite_status:ok
aof_last_write_status:ok
aof_last_cow_size:0
aof_current_size:40803
aof_base_size:0
aof_pending_rewrite:0
aof_buffer_length:0
aof_rewrite_buffer_length:0
aof_pending_bio_fsync:0
aof_delayed_fsync:0

# Stats
total_connections_received:12
total_commands_processed:1019
instantaneous_ops_per_sec:0
total_net_input_bytes:41255
total_net_output_bytes:46481
instantaneous_input_kbps:0.00
instantaneous_output_kbps:0.00
rejected_connections:0
sync_full:0
sync_partial_ok:0
sync_partial_err:0
expired_keys:0
expired_stale_perc:0.00
expired_time_cap_reached_count:0
evicted_keys:0
keyspace_hits:0
keyspace_misses:0
pubsub_channels:0
pubsub_patterns:0
latest_fork_usec:523
migrate_cached_sockets:0
slave_expires_tracked_keys:0
active_defrag_hits:0
active_defrag_misses:0
active_defrag_key_hits:0
active_defrag_key_misses:0

# Replication
role:master
connected_slaves:0
master_replid:518de7012facc8a7fe780ed4eb5f4de015f01d56
master_replid2:0000000000000000000000000000000000000000
master_repl_offset:0
second_repl_offset:-1
repl_backlog_active:0
repl_backlog_size:1048576
repl_backlog_first_byte_offset:0
repl_backlog_histlen:0

# CPU
used_cpu_sys:0.365552
used_cpu_user:0.570244
used_cpu_sys_children:0.000000
used_cpu_user_children:0.001215

# Cluster
cluster_enabled:0

# Keyspace
db0:keys=1000,expires=0,avg_ttl=0

info

可以在INFO 后补充筛选内容

#查看当前节点CPU信息
127.0.0.1:6379> info CPU
# CPU
used_cpu_sys:0.508881
used_cpu_user:0.848135
used_cpu_sys_children:0.000000
used_cpu_user_children:0.003046

#查看当前节点Server信息
127.0.0.1:6379> info Server
# Server
redis_version:5.0.14
redis_git_sha1:00000000
redis_git_dirty:0
redis_build_id:5d32a2d9ed5f67d5
redis_mode:standalone
os:Linux 4.15.0-210-generic x86_64
arch_bits:64
multiplexing_api:epoll
atomicvar_api:atomic-builtin
gcc_version:7.5.0
process_id:6069
run_id:0e67fcd27ff6ae2589ff90ac2516bd52269f2965
tcp_port:6379
uptime_in_seconds:1358
uptime_in_days:0
hz:10
configured_hz:10
lru_clock:5746346
executable:/app/redis/bin/redis-server
config_file:/app/redis/etc/redis_6379.conf

2、SELECT

切换数据库，类似于MySQL是 USE DATABASES;

在Cluster模式下不支持多DB模式，会出现以下错误提示

10.0.0.20:6379> info cluster
# Cluster
cluster_enabled:1
10.0.0.20:6379> select 1
(error) ERR SELECT is not allowed in cluster mode

127.0.0.1:6379> help select

  SELECT index
  summary: Change the selected database for the current connection
  since: 1.0.0
  group: connection

127.0.0.1:6379> select 1
OK
127.0.0.1:6379[1]> select 2
OK
127.0.0.1:6379[2]> select 3
OK
127.0.0.1:6379[3]> 

select

3、KEYS

查看当前数据库下所有的key（数据量大时会对数据库造成巨大压力，此命令慎用）

此命令仅查询当前db下的数据

127.0.0.1:6379> select 1
OK
127.0.0.1:6379[1]> keys *
(empty list or set)
127.0.0.1:6379[1]> info KeySpace
# Keyspace
db0:keys=1000,expires=0,avg_ttl=0

127.0.0.1:6379> help keys

  KEYS pattern
  summary: Find all keys matching the given pattern
  since: 1.0.0
  group: generic

#？ 占位符
127.0.0.1:6379> keys key_?
 1) "key_8"
 2) "key_5"
 3) "key_4"
 4) "key_9"
 5) "key_0"
 6) "key_2"
 7) "key_1"
 8) "key_3"
 9) "key_6"
10) "key_7"
127.0.0.1:6379> keys key_2?
 1) "key_27"
 2) "key_28"
 3) "key_22"
 4) "key_26"
 5) "key_21"
 6) "key_20"
 7) "key_25"
 8) "key_23"
 9) "key_24"
10) "key_29"

#* 通配
#127.0.0.1:6379> keys key_9*
  1) "key_995"
  2) "key_957"
  3) "key_988"
  4) "key_98"
  5) "key_990"
  6) "key_959"
  7) "key_949"
  8) "key_984"
  9) "key_999"
 10) "key_950"
 11) "key_976"
 12) "key_912"
 13) "key_991"
 14) "key_944"
 15) "key_987"
 16) "key_954"
 17) "key_981"
 18) "key_951"
 19) "key_998"
 20) "key_916"
 21) "key_986"
 22) "key_933"
 23) "key_996"
 24) "key_918"
 25) "key_942"
 26) "key_906"
 27) "key_925"
 28) "key_965"
 29) "key_964"
 30) "key_917"
 31) "key_9"
 32) "key_95"
 33) "key_994"
 34) "key_94"
 35) "key_961"
 36) "key_901"
 37) "key_962"
 38) "key_909"
 39) "key_971"
 40) "key_966"
 41) "key_968"
 42) "key_913"
 43) "key_960"
 44) "key_937"
 45) "key_977"
 46) "key_90"
 47) "key_926"
 48) "key_93"
 49) "key_955"
 50) "key_970"
 51) "key_939"
 52) "key_908"
 53) "key_929"
 54) "key_972"
 55) "key_902"
 56) "key_948"
 57) "key_956"
 58) "key_930"
 59) "key_978"
 60) "key_99"
 61) "key_924"
 62) "key_915"
 63) "key_943"
 64) "key_932"
 65) "key_928"
 66) "key_914"
 67) "key_982"
 68) "key_905"
 69) "key_974"
 70) "key_979"
 71) "key_940"
 72) "key_941"
 73) "key_958"
 74) "key_997"
 75) "key_993"
 76) "key_922"
 77) "key_92"
 78) "key_980"
 79) "key_934"
 80) "key_911"
 81) "key_946"
 82) "key_923"
 83) "key_945"
 84) "key_992"
 85) "key_969"
 86) "key_921"
 87) "key_910"
 88) "key_936"
 89) "key_983"
 90) "key_903"
 91) "key_989"
 92) "key_931"
 93) "key_919"
 94) "key_953"
 95) "key_947"
 96) "key_96"
 97) "key_935"
 98) "key_91"
 99) "key_907"
100) "key_952"
101) "key_927"
102) "key_967"
103) "key_904"
104) "key_900"
105) "key_938"
106) "key_973"
107) "key_97"
108) "key_920"
109) "key_985"
110) "key_963"
111) "key_975"

#展示当前数据库内的所有key
127.0.0.1:6379> keys *
......
 987) "key_172"
 988) "key_64"
 989) "key_79"
 990) "key_801"
 991) "key_502"
 992) "key_144"
 993) "key_514"
 994) "key_615"
 995) "key_197"
 996) "key_84"
 997) "key_681"
 998) "key_572"
 999) "key_656"
1000) "key_805"

4、BGSAVE

手动触发后台执行save操作

127.0.0.1:6379>
127.0.0.1:6379> help bgsave

  BGSAVE -
  summary: Asynchronously save the dataset to disk
  since: 1.0.0
  group: server

127.0.0.1:6379> bgsave
Background saving started

5、DBSIZE

返回当前数据库下的所有key数量

127.0.0.1:6379> help dbsize

  DBSIZE -
  summary: Return the number of keys in the selected database
  since: 1.0.0
  group: server

127.0.0.1:6379> dbsize
(integer) 1000
127.0.0.1:6379> select 1
OK
127.0.0.1:6379[1]> dbsize
(integer) 0

6、FLUSHDB

强制清空当前数据库中的所有key，不会影响其他db中的数据，谨慎使用

127.0.0.1:6379> help flushdb

  FLUSHDB [ASYNC]
  summary: Remove all keys from the current database
  since: 1.0.0
  group: server

127.0.0.1:6379[1]> info KeySpace
# Keyspace
db0:keys=1000,expires=0,avg_ttl=0
db1:keys=4,expires=0,avg_ttl=0

#清空db1中的所有键值，不会影响到db0中的数据
127.0.0.1:6379[1]> flushdb
OK
127.0.0.1:6379[1]> info KeySpace
# Keyspace
db0:keys=1000,expires=0,avg_ttl=0
127.0.0.1:6379[1]> 

7、FLUSHALL

强制清空当前redis节点上所有数据库中的所有key，即删除当前节点所有数据，谨慎使用，必要情况建议禁用此命令

127.0.0.1:6379> info KeySpace
# Keyspace
db0:keys=1000,expires=0,avg_ttl=0
db1:keys=4,expires=0,avg_ttl=0
127.0.0.1:6379> flushall
OK
127.0.0.1:6379> info KeySpace
# Keyspace
127.0.0.1:6379> 

8、SHUTDOWN

时间复杂度：O(N) N为需要保存的数据库键数量

SHUTDOWN执行过程：

• 停止所有客户端连接
• 如果至少有一个保存节点在等待，执行SAVE操作
• 如果AOF开启，更新AOF内容
• 关闭 Redis Server

如果开启了持久化配置，SHUTDOWN命令可以保障服务器正常关闭而数据不丢失

如果单纯执行SAVE之后，执行 QUIT 命令，则无法保证数据不丢失，SAVE执行完成后，执行 QUIT 命令的过程中，服务器可能依旧存在与客户端的访问连接，会造成这期间数据的丢失。

127.0.0.1:6379> help shutdown

  SHUTDOWN [NOSAVE|SAVE]
  summary: Synchronously save the dataset to disk and then shut down the server
  since: 1.0.0
  group: server

127.0.0.1:6379> shutdown
not connected>
not connected>
not connected> exit

[root@Client-Ubuntu-1804-250:~]# ps -aux | grep redis | grep ^grep
[root@Client-Ubuntu-1804-250:~]# ss -ntlp
State      Recv-Q      Send-Q             Local Address:Port             Peer Address:Port
LISTEN     0           128                127.0.0.53%lo:53                    0.0.0.0:*          users:(("systemd-resolve",pid=867,fd=13))
LISTEN     0           128                      0.0.0.0:22                    0.0.0.0:*          users:(("sshd",pid=978,fd=3))
LISTEN     0           128                    127.0.0.1:6010                  0.0.0.0:*          users:(("sshd",pid=1661,fd=10))
LISTEN     0           128                    127.0.0.1:6011                  0.0.0.0:*          users:(("sshd",pid=1661,fd=15))
LISTEN     0           128                         [::]:22                       [::]:*          users:(("sshd",pid=978,fd=4))
LISTEN     0           128                        [::1]:6010                     [::]:*          users:(("sshd",pid=1661,fd=9))
LISTEN     0           128                        [::1]:6011                     [::]:*          users:(("sshd",pid=1661,fd=12)) 

禁用Redis命令（rename配置）

可通过配置文件中的 rename-comand <command> "" 对原有命令进行重命名（通常用于对高危命令进行管控）

#在启用aof情况下，禁用或重命名命令可能会导致redis服务无法启动，是因为实例在之前执行被重命名的命令，导致加载aof时，命令执行失败
6682:C 07 May 2023 23:20:57.411 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo
6682:C 07 May 2023 23:20:57.411 # Redis version=5.0.14, bits=64, commit=00000000, modified=0, pid=6682, just started
6682:C 07 May 2023 23:20:57.411 # Configuration loaded
6682:C 07 May 2023 23:20:57.411 * supervised by systemd, will signal readiness
6682:M 07 May 2023 23:20:57.417 * Running mode=standalone, port=6379.
6682:M 07 May 2023 23:20:57.419 # Server initialized
6682:M 07 May 2023 23:20:57.420 # Unknown command 'flushdb' reading the append only file

解决方案：

1、禁用aof选项

2、修改配置重启服务之前，执行 bgrewriteaof 重新生成aof内容

# Command renaming.
#
# It is possible to change the name of dangerous commands in a shared
# environment. For instance the CONFIG command may be renamed into something
# hard to guess so that it will still be available for internal-use tools
# but not available for general clients.
#
# Example:
#
# rename-command CONFIG b840fc02d524045429941cc15f59e41cb7be6c52
#
# It is also possible to completely kill a command by renaming it into
# an empty string:
#
# rename-command CONFIG ""
#
# Please note that changing the name of commands that are logged into the
# AOF file or transmitted to replicas may cause problems.

renmae-comand FLUSHALL ""
rename-comand FULSHDB "REMOVE-THIS-DATABASE"

127.0.0.1:6379> info keySpace
# Keyspace
db0:keys=1000,expires=0,avg_ttl=0
127.0.0.1:6379> flushall
(error) ERR unknown command `flushall`, with args beginning with:
127.0.0.1:6379> flushdb
(error) ERR unknown command `flushdb`, with args beginning with:
127.0.0.1:6379> info keySpace
# Keyspace
db0:keys=1000,expires=0,avg_ttl=0
127.0.0.1:6379>
127.0.0.1:6379> REMOVE-THIS-DATABASE
OK
127.0.0.1:6379> info keySpace
# Keyspace
127.0.0.1:6379>