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!(#)(#) The Redis `INFO` command returns various information and statistics about the Redis server in a format that is easy to understand and read. By providing an optional parameter `section`, you can limit the command to return only specific sections of information: * **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 for the Redis server (used by 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: Clock incremented every minute, used for LRU management * **clients**: Information about connected clients, including the following fields: * connected_clients: Number of connected clients (excluding those connected via slave servers) * client_longest_output_list: Longest output list among currently connected clients * client_longest_input_buf: Largest input buffer among 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 amount of memory allocated by Redis allocator, in bytes * used_memory_human: Total amount of memory allocated by Redis, returned in human-readable format * used_memory_rss: Total memory allocated by Redis from the operating system's perspective (commonly known as resident set size). This value matches the output of commands like `top` and `ps`. * used_memory_peak: Peak memory usage of Redis (in bytes) * used_memory_peak_human: Peak memory usage of Redis, returned in 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. Can be libc, jemalloc, or tcmalloc. In an ideal scenario, the value of `used_memory_rss` should be only slightly higher than `used_memory`. When `rss > used` and the difference between the two values is significant, it indicates memory fragmentation (either internal or external). The memory fragmentation ratio can be observed through the `mem_fragmentation_ratio` value. When `used > rss`, it means part of Redis's memory has been swapped out to the operating system's swap space, which may cause noticeable delays during operations. When Redis releases memory, the allocator may or may not return it to the operating system. If Redis releases memory but does not return it to the operating system, the `used_memory` value might differ from the memory usage shown by the OS. Checking the `used_memory_peak` value can help verify whether this situation has occurred. * **persistence**: Information related to RDB and AOF * **stats**: General statistics * **replication**: Master/Slave replication information * **cpu**: CPU usage statistics * **commandstats**: Redis command statistics * **cluster**: Redis cluster information * **keyspace**: Database-related statistics ### Syntax The basic syntax for the Redis `INFO` command is as follows: redis 127.0.0.1:6379> INFO ### Available Versions >= 1.0.0 ### Return Value String, a collection of text lines. ### Examples 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 # Keyspace !(#)(#)