4.2 查看Redis服务器的详细信息

4.2.1 通过INFO命令查看服务器信息

• INFO

  • 功能:查看服务端相关信息

例:

127.0.0.1:6379> INFO
# Server
redis_version:6.2.6
redis_git_sha1:00000000
redis_git_dirty:0
redis_build_id:b61f37314a089f19
redis_mode:standalone
os:Linux 5.15.49-linuxkit x86_64
arch_bits:64
multiplexing_api:epoll
atomicvar_api:atomic-builtin
gcc_version:10.2.1
process_id:1
process_supervised:no
run_id:ec3f7b5d6eda8fa1c55555f82ede6dfd23e9a50c
tcp_port:6379
server_time_usec:1691911379981145
uptime_in_seconds:300
uptime_in_days:0
hz:10
configured_hz:10
lru_clock:14189779
executable:/data/redis-server
config_file:
io_threads_active:0

# Clients
connected_clients:1
cluster_connections:0
maxclients:10000
client_recent_max_input_buffer:24
client_recent_max_output_buffer:0
blocked_clients:0
tracking_clients:0
clients_in_timeout_table:0

# Memory
used_memory:873648
used_memory_human:853.17K
used_memory_rss:7856128
used_memory_rss_human:7.49M
used_memory_peak:933848
used_memory_peak_human:911.96K
used_memory_peak_perc:93.55%
used_memory_overhead:830384
used_memory_startup:809880
used_memory_dataset:43264
used_memory_dataset_perc:67.85%
allocator_allocated:1071104
allocator_active:1290240
allocator_resident:3805184
total_system_memory:8346099712
total_system_memory_human:7.77G
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:1.20
allocator_frag_bytes:219136
allocator_rss_ratio:2.95
allocator_rss_bytes:2514944
rss_overhead_ratio:2.06
rss_overhead_bytes:4050944
mem_fragmentation_ratio:9.46
mem_fragmentation_bytes:7025240
mem_not_counted_for_evict:0
mem_replication_backlog:0
mem_clients_slaves:0
mem_clients_normal:20504
mem_aof_buffer:0
mem_allocator:jemalloc-5.1.0
active_defrag_running:0
lazyfree_pending_objects:0
lazyfreed_objects:0

# Persistence
loading:0
current_cow_size:0
current_cow_size_age:0
current_fork_perc:0.00
current_save_keys_processed:0
current_save_keys_total:0
rdb_changes_since_last_save:20
rdb_bgsave_in_progress:0
rdb_last_save_time:1691911079
rdb_last_bgsave_status:ok
rdb_last_bgsave_time_sec:-1
rdb_current_bgsave_time_sec:-1
rdb_last_cow_size:0
aof_enabled:0
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
module_fork_in_progress:0
module_fork_last_cow_size:0

# Stats
total_connections_received:1
total_commands_processed:3
instantaneous_ops_per_sec:0
total_net_input_bytes:74
total_net_output_bytes:20555
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
expire_cycle_cpu_milliseconds:5
evicted_keys:0
keyspace_hits:0
keyspace_misses:0
pubsub_channels:0
pubsub_patterns:0
latest_fork_usec:0
total_forks:0
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
tracking_total_keys:0
tracking_total_items:0
tracking_total_prefixes:0
unexpected_error_replies:0
total_error_replies:0
dump_payload_sanitizations:0
total_reads_processed:4
total_writes_processed:3
io_threaded_reads_processed:0
io_threaded_writes_processed:0

# Replication
role:master
connected_slaves:0
master_failover_state:no-failover
master_replid:557e052fd9196b70141b0e18a6c609dfceb06773
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:0.487641
used_cpu_user:0.287673
used_cpu_sys_children:0.003459
used_cpu_user_children:0.001504
used_cpu_sys_main_thread:0.485370
used_cpu_user_main_thread:0.284587

# Modules

# Errorstats

# Cluster
cluster_enabled:0

# Keyspace

属性	含义
Server	服务端相关信息
Clients	已连接的客户端信息
Memory	Redis服务端内存相关信息
Persistence	持久化相关信息
Stats	和服务端相关的统计信息
Replication	主从复制相关信息
CPU	服务端所在机器的CPU相关信息
Cluster	Redis集群相关信息
Keyspace	和Redis数据库相关的统计信息.比如键的数量和超时时间等

4.2.2 查看客户端连接状况

• INFO CLIENTS

  • 功能:查看客户端的连接情况

例:

127.0.0.1:6379> INFO CLIENTS
# Clients
connected_clients:1
cluster_connections:0
maxclients:10000
client_recent_max_input_buffer:16
client_recent_max_output_buffer:0
blocked_clients:0
tracking_clients:0
clients_in_timeout_table:0

其中:

• connected_clients:正在连接的客户端数量

• maxclients:服务端允许的最大连接数

4.2.3 观察最大连接数

• INFO STATS

  • 功能:查看服务端运行情况

INFO STATS命令详解

例:

127.0.0.1:6379> INFO STATS
# Stats
total_connections_received:1
total_commands_processed:6
instantaneous_ops_per_sec:0
total_net_input_bytes:150
total_net_output_bytes:24839
instantaneous_input_kbps:0.01
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
expire_cycle_cpu_milliseconds:12
evicted_keys:0
keyspace_hits:0
keyspace_misses:0
pubsub_channels:0
pubsub_patterns:0
latest_fork_usec:0
total_forks:0
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
tracking_total_keys:0
tracking_total_items:0
tracking_total_prefixes:0
unexpected_error_replies:0
total_error_replies:0
dump_payload_sanitizations:0
total_reads_processed:7
total_writes_processed:6
io_threaded_reads_processed:0
io_threaded_writes_processed:0

其中:

• rejected_connections:因超过最大连接数而被拒绝的客户端连接次数

查看最大连接数:

127.0.0.1:6379> CONFIG GET maxclients
1) "maxclients"
2) "10000"

可以看到,一般情况下是不会出现rejected_connections大于0的情况

4.2.4 查看每秒执行多少条指令

在INFO STATS命令的返回值中,有一项名为instantaneous_ops_per_sec.

• instantaneous_ops_per_sec:表示当前每秒执行的指令数量

若集群中某台Redis服务器中该数值过大或过小,就需要观察负载均衡的相关配置了.或者当数据库压力较大而通过该命令发现作为缓存的Redis服务器执行的指令过少时,就需要调整缓存策略

4.2.5 观察内存用量

• INFO MEMORY

  • 功能:观察当前Redis服务器的内存使用情况

由于Redis是在内存中缓存数据,如果缓存数据太多,或者大量键没有设置过期时间(expired time),就会造成内存使用过大,从而导致OOM问题.此时需要通过INFO MEMORY命令观察Redis服务器的内存使用情况.

127.0.0.1:6379> INFO MEMORY
# Memory
used_memory:871904
used_memory_human:851.47K
used_memory_rss:7839744
used_memory_rss_human:7.48M
used_memory_peak:933848
used_memory_peak_human:911.96K
used_memory_peak_perc:93.37%
used_memory_overhead:830392
used_memory_startup:809880
used_memory_dataset:41512
used_memory_dataset_perc:66.93%
allocator_allocated:1133568
allocator_active:1368064
allocator_resident:3883008
total_system_memory:8346099712
total_system_memory_human:7.77G
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:1.21
allocator_frag_bytes:234496
allocator_rss_ratio:2.84
allocator_rss_bytes:2514944
rss_overhead_ratio:2.02
rss_overhead_bytes:3956736
mem_fragmentation_ratio:9.44
mem_fragmentation_bytes:7008848
mem_not_counted_for_evict:0
mem_replication_backlog:0
mem_clients_slaves:0
mem_clients_normal:20512
mem_aof_buffer:0
mem_allocator:jemalloc-5.1.0
active_defrag_running:0
lazyfree_pending_objects:0
lazyfreed_objects:0

其中:

• used_memory_human:以人类可读形式展示Redis已使用的内存

• used_memory_peak_human:以人类可读形式展示Redis使用的内存峰值

• used_memory_lua_human:以人类可读形式展示LUA脚本占用的内存大小

• used_memory_scripts_human:以人类可读形式展示脚本占用的内存大小

• mem_clients_slaves:因客户端主从复制而使用的内存大小

4.2.6 通过COMMAND命令查看Redis命令

• COMMAND

  • 功能:返回Redis的命令信息

例:

127.0.0.1:6379> COMMAND
  1) 1) "psubscribe"
     2) (integer) -2
     3) 1) pubsub
        2) noscript
        3) loading
        4) stale
     4) (integer) 0
     5) (integer) 0
     6) (integer) 0
     7) 1) @pubsub
        2) @slow
  2) 1) "lpos"
     2) (integer) -3
     3) 1) readonly
     4) (integer) 1
     5) (integer) 1
     6) (integer) 1
     7) 1) @read
        2) @list
        3) @slow
  3) 1) "rpushx"
     2) (integer) -3
     3) 1) write
        2) denyoom
        3) fast
     4) (integer) 1
     5) (integer) 1
     6) (integer) 1
     7) 1) @write
        2) @list
        3) @fast
  4) 1) "setbit"
     2) (integer) 4
     3) 1) write
        2) denyoom
     4) (integer) 1
     5) (integer) 1
     6) (integer) 1
     7) 1) @write
        2) @bitmap
        3) @slow
  5) 1) "georadius_ro"
     2) (integer) -6
     3) 1) readonly
     4) (integer) 1
     5) (integer) 1
     6) (integer) 1
     7) 1) @read
        2) @geo
        3) @slow
  6) 1) "command"
     2) (integer) -1
     3) 1) random
        2) loading
        3) stale
     4) (integer) 0
     5) (integer) 0
     6) (integer) 0
     7) 1) @slow
        2) @connection
  7) 1) "debug"
     2) (integer) -2
     3) 1) admin
        2) noscript
        3) loading
        4) stale
     4) (integer) 0
     5) (integer) 0
     6) (integer) 0
     7) 1) @admin
        2) @slow
        3) @dangerous
  8) 1) "bzpopmin"
     2) (integer) -3
     3) 1) write
        2) noscript
        3) fast
     4) (integer) 1
     5) (integer) -2
     6) (integer) 1
     7) 1) @write
        2) @sortedset
        3) @fast
        4) @blocking
  9) 1) "xrevrange"
     2) (integer) -4
     3) 1) readonly
     4) (integer) 1
     5) (integer) 1
     6) (integer) 1
     7) 1) @read
        2) @stream
        3) @slow
...
223) 1) "hrandfield"
     2) (integer) -2
     3) 1) readonly
        2) random
     4) (integer) 1
     5) (integer) 1
     6) (integer) 1
     7) 1) @read
        2) @hash
        3) @slow
224) 1) "scan"
     2) (integer) -2
     3) 1) readonly
        2) random
     4) (integer) 0
     5) (integer) 0
     6) (integer) 0
     7) 1) @keyspace
        2) @read
        3) @slow

4.2.7 查看指定Redis命令的信息

• COMMAND INFO

  • 语法:COMMAND INFO key [key ...]

  • 功能:查看指定命令的详细信息

例:

127.0.0.1:6379> COMMAND INFO set
1) 1) "set"
   2) (integer) -3
   3) 1) write
      2) denyoom
   4) (integer) 1
   5) (integer) 1
   6) (integer) 1
   7) 1) @write
      2) @string
      3) @slow

127.0.0.1:6379> COMMAND INFO get
1) 1) "get"
   2) (integer) 2
   3) 1) readonly
      2) fast
   4) (integer) 1
   5) (integer) 1
   6) (integer) 1
   7) 1) @read
      2) @string
      3) @fast

4.2.8 获取指定命令的所有键

• COMMAND GETKEYS

  • 语法:COMMAND GETKEYS command

  • 功能:获取command命令中所有的键

例:

127.0.0.1:6379> COMMAND GETKEYS MSET name Peter age 18 score 100
1) "name"
2) "age"
3) "score"

MSET命令可以设置多个键值对,前边加上COMMAND GETKEYS即可获得该命令操作的所有key名

注:COMMAND GETKEYS命令后的command部分实际上并没有真正执行

127.0.0.1:6379> GET name
(nil)
127.0.0.1:6379> GET age
(nil)
127.0.0.1:6379> GET score
(nil)

例:

127.0.0.1:6379> COMMAND GETKEYS SET name Mary
1) "name"

127.0.0.1:6379> GET name
(nil)