Redis Info Command
The Redis Info command returns various information and statistics about the Redis server in an easy-to-understand and readable format.
By providing an optional parameter section, the command can return information for a specific section:
-
server: General Redis server information, including the following fields:
redis_version: Redis server version
redis_git_sha1: Git SHA1
redis_git_dirty: Git dirty flag
os: Host operating system of the Redis server
arch_bits: Architecture (32 or 64 bits)
multiplexing_api: Event handling mechanism used by Redis
gcc_version: GCC version used to compile Redis
process_id: PID of the server process
run_id: Random identifier of the Redis server (used for Sentinel and clustering)
tcp_port: TCP/IP listening port
uptime_in_seconds: Number of seconds since the Redis server started
uptime_in_days: Number of days since the Redis server started
lru_clock: Incremental clock in minutes, used for LRU management
-
clients: Connected client information, including the following fields:
connected_clients: Number of connected clients (excluding clients connected via slave servers)
client_longest_output_list: Longest output list among the currently connected clients
client_longest_input_buf: Largest input buffer among the currently connected clients
blocked_clients: Number of clients waiting for blocking commands (BLPOP, BRPOP, BRPOPLPUSH)
-
memory: Memory information, including the following fields:
used_memory: Total memory allocated by the Redis allocator, in bytes
used_memory_human: Total memory allocated by Redis in a human-readable format
used_memory_rss: Total memory allocated by Redis from the operating system's perspective (resident set size). This value matches the output of commands like
topandps.used_memory_peak: Peak memory consumption of Redis, in bytes
used_memory_peak_human: Peak memory consumption of Redis in a human-readable format
used_memory_lua: Memory size used by the Lua engine, in bytes
mem_fragmentation_ratio: Ratio between used_memory_rss and used_memory
mem_allocator: Memory allocator used by Redis, specified at compile time. It can be libc, jemalloc, or tcmalloc.
Ideally, the value of used_memory_rss should be only slightly higher than used_memory.
When rss > used and the difference between the two is significant, it indicates the presence of (internal or external) memory fragmentation.
The ratio of memory fragmentation can be seen from the value of mem_fragmentation_ratio.
When used > rss, it indicates that part of Redis's memory has been swapped out by the operating system, which may cause significant delays in operations.
When Redis frees memory, the allocator may or may not return the memory to the operating system.
If Redis frees memory but does not return it to the operating system, the value of used_memory may not match the memory usage shown by the operating system for Redis.
Checking the value of used_memory_peak can verify if this situation has occurred.
-
persistence: Information about RDB and AOF
-
stats: General statistics
-
replication: Master/slave replication information
-
cpu: CPU computation statistics
-
commandstats: Redis command statistics
-
cluster: Redis cluster information
-
keyspace: Statistics related to databases
Syntax
The basic syntax of the redis Info command is as follows:
redis 127.0.0.1:6379> INFO [section]
Available Versions
= 1.0.0
Return Value
String, a collection of text lines.
Example
redis 127.0.0.1:6379> INFO
# Server
redis_version:2.5.9
redis_git_sha1:473f3090
redis_git_dirty:0
os: Linux 3.3.7-1-ARCH i686 arch_bits: 32 multiplexing_api: epoll gcc_version: 4.7.0 process_id: 8104 run_id: bc9e20c6f0aac67d0d396ab950940ae4d1479ad1 tcp_port: 6379 uptime_in_seconds: 7 uptime_in_days: 0 lru_clock: 1680564
Clients
connected_clients: 1 client_longest_output_list: 0 client_biggest_input_buf: 0 blocked_clients: 0
Memory
used_memory: 439304 used_memory_human: 429.01K used_memory_rss: 13897728 used_memory_peak: 401776 used_memory_peak_human: 392.36K used_memory_lua: 20480 mem_fragmentation_ratio: 31.64 mem_allocator: jemalloc-3.0.0
Persistence
loading: 0 rdb_changes_since_last_save: 0 rdb_bgsave_in_progress: 0 rdb_last_save_time: 1338011402 rdb_last_bgsave_status: ok rdb_last_bgsave_time_sec: -1 rdb_current_bgsave_time_sec: -1 aof_enabled: 0 aof_rewrite_in_progress: 0 aof_rewrite_scheduled: 0 aof_last_rewrite_time_sec: -1 aof_current_rewrite_time_sec: -1
Stats
total_connections_received: 1 total_commands_processed: 0 instantaneous_ops_per_sec: 0 rejected_connections: 0 expired_keys: 0 evicted_keys: 0 keyspace_hits: 0 keyspace_misses: 0 pubsub_channels: 0 pubsub_patterns: 0 latest_fork_usec: 0
Replication
role: master connected_slaves: 0
CPU
used_cpu_sys: 0.03 used_cpu_user: 0.01 used_cpu_sys_children: 0.00 used_cpu_user_children: 0.00