来自redis官档对于 INFO命令的解析。

大家也可以在http://redis.io/commands#server中找到CLIENT LIST、SLOWLOG等命令的官方解释。

The INFO command returns information and statistics about the server in a format that is simple to parse by computers and easy to read by humans.

The optional parameter can be used to select a specific section of information:

• server: General information about the Redis server
• clients: Client connections section
• memory: Memory consumption related information
• persistence: RDB and AOF related information
• stats: General statistics
• replication: Master/slave replication information
• cpu: CPU consumption statistics
• commandstats: Redis command statistics
• cluster: Redis Cluster section
• keyspace: Database related statistics

It can also take the following values:

• all: Return all sections
• default: Return only the default set of sections

When no parameter is provided, the default option is assumed.

Return value

Bulk reply: as a collection of text lines.

Lines can contain a section name (starting with a # character) or a property. All the properties are in the form offield:value terminated by rn.

# Server
redis_version:2.5.13
redis_git_sha1:2812b945
redis_git_dirty:0
os:Linux 2.6.32.16-linode28 i686
arch_bits:32
multiplexing_api:epoll
gcc_version:4.4.1
process_id:8107
run_id:2e0192d968d1d4a36a927413d3b4ae4aa46e7ccd
tcp_port:6379
uptime_in_seconds:10335010
uptime_in_days:119
lru_clock:537661

# Clients
connected_clients:8
client_longest_output_list:0
client_biggest_input_buf:0
blocked_clients:0

# Memory
used_memory:1478200
used_memory_human:1.41M
used_memory_rss:2007040
used_memory_peak:1737576
used_memory_peak_human:1.66M
used_memory_lua:20480
mem_fragmentation_ratio:1.36
mem_allocator:jemalloc-3.0.0

# Persistence
loading:0
rdb_changes_since_last_save:235
rdb_bgsave_in_progress:0
rdb_last_save_time:1368525256
rdb_last_bgsave_status:ok
rdb_last_bgsave_time_sec:0
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
aof_last_bgrewrite_status:ok

# Stats
total_connections_received:4673
total_commands_processed:26601043
instantaneous_ops_per_sec:0
rejected_connections:0
expired_keys:26239
evicted_keys:0
keyspace_hits:6439648
keyspace_misses:1588733
pubsub_channels:0
pubsub_patterns:0
latest_fork_usec:786

# Replication
role:master
connected_slaves:0

# CPU
used_cpu_sys:2999.93
used_cpu_user:1354.42
used_cpu_sys_children:165.93
used_cpu_user_children:401.32

# Keyspace
db0:keys=11071,expires=1

Notes

Please note depending on the version of Redis some of the fields have been added or removed. A robust client application should therefore parse the result of this command by skipping unknown properties, and gracefully handle missing fields.

Here is the description of fields for Redis >= 2.4.

Here is the meaning of all fields in the server section:

• redis_version: Version of the Redis server
• redis_git_sha1: Git SHA1
• redis_git_dirty: Git dirty flag
• os: Operating system hosting the Redis server
• arch_bits: Architecture (32 or 64 bits)
• multiplexing_api: event loop mechanism used by Redis
• gcc_version: Version of the GCC compiler used to compile the Redis server
• process_id: PID of the server process
• run_id: Random value identifying the Redis server (to be used by Sentinel and Cluster)
• tcp_port: TCP/IP listen port
• uptime_in_seconds: Number of seconds since Redis server start
• uptime_in_days: Same value expressed in days
• lru_clock: Clock incrementing every minute, for LRU management

Here is the meaning of all fields in the clients section:

• connected_clients: Number of client connections (excluding connections from slaves)
• client_longest_output_list: longest output list among current client connections
• client_biggest_input_buf: biggest input buffer among current client connections
• blocked_clients: Number of clients pending on a blocking call (BLPOP, BRPOP, BRPOPLPUSH)

Here is the meaning of all fields in the memory section:

• used_memory: total number of bytes allocated by Redis using its allocator (either standard libc, jemalloc, or an alternative allocator such astcmalloc
• used_memory_human: Human readable representation of previous value
• used_memory_rss: Number of bytes that Redis allocated as seen by the operating system (a.k.a resident set size). This is the number reported by tools such as top and ps.
• used_memory_peak: Peak memory consumed by Redis (in bytes)
• used_memory_peak_human: Human readable representation of previous value
• used_memory_lua: Number of bytes used by the Lua engine
• mem_fragmentation_ratio: Ratio between used_memory_rss and used_memory
• mem_allocator: Memory allocator, chosen at compile time.

Ideally, the used_memory_rss value should be only slightly higher than used_memory. When rss >> used, a large difference means there is memory fragmentation (internal or external), which can be evaluated by checking mem_fragmentation_ratio. When used >> rss, it means part of Redis memory has been swapped off by the operating system: expect some significant latencies.

Because Redis does not have control over how its allocations are mapped to memory pages, high used_memory_rss is often the result of a spike in memory usage.

When Redis frees memory, the memory is given back to the allocator, and the allocator may or may not give the memory back to the system. There may be a discrepancy between the used_memory value and memory consumption as reported by the operating system. It may be due to the fact memory has been used and released by Redis, but not given back to the system. The used_memory_peak value is generally useful to check this point.

Here is the meaning of all fields in the persistence section:

• loading: Flag indicating if the load of a dump file is on-going
• rdb_changes_since_last_save: Number of changes since the last dump
• rdb_bgsave_in_progress: Flag indicating a RDB save is on-going
• rdb_last_save_time: Epoch-based timestamp of last successful RDB save
• rdb_last_bgsave_status: Status of the last RDB save operation
• rdb_last_bgsave_time_sec: Duration of the last RDB save operation in seconds
• rdb_current_bgsave_time_sec: Duration of the on-going RDB save operation if any
• aof_enabled: Flag indicating AOF logging is activated
• aof_rewrite_in_progress: Flag indicating a AOF rewrite operation is on-going
• aof_rewrite_scheduled: Flag indicating an AOF rewrite operation will be scheduled once the on-going RDB save is complete.
• aof_last_rewrite_time_sec: Duration of the last AOF rewrite operation in seconds
• aof_current_rewrite_time_sec: Duration of the on-going AOF rewrite operation if any
• aof_last_bgrewrite_status: Status of the last AOF rewrite operation

changes_since_last_save refers to the number of operations that produced some kind of changes in the dataset since the last time eitherSAVE or BGSAVE was called.

If AOF is activated, these additional fields will be added:

• aof_current_size: AOF current file size
• aof_base_size: AOF file size on latest startup or rewrite
• aof_pending_rewrite: Flag indicating an AOF rewrite operation will be scheduled once the on-going RDB save is complete.
• aof_buffer_length: Size of the AOF buffer
• aof_rewrite_buffer_length: Size of the AOF rewrite buffer
• aof_pending_bio_fsync: Number of fsync pending jobs in background I/O queue
• aof_delayed_fsync: Delayed fsync counter

If a load operation is on-going, these additional fields will be added:

• loading_start_time: Epoch-based timestamp of the start of the load operation
• loading_total_bytes: Total file size
• loading_loaded_bytes: Number of bytes already loaded
• loading_loaded_perc: Same value expressed as a percentage
• loading_eta_seconds: ETA in seconds for the load to be complete

Here is the meaning of all fields in the stats section:

• total_connections_received: Total number of connections accepted by the server
• total_commands_processed: Total number of commands processed by the server
• instantaneous_ops_per_sec: Number of commands processed per second
• rejected_connections: Number of connections rejected because of maxclients limit
• expired_keys: Total number of key expiration events
• evicted_keys: Number of evicted keys due to maxmemory limit
• keyspace_hits: Number of successful lookup of keys in the main dictionary
• keyspace_misses: Number of failed lookup of keys in the main dictionary
• pubsub_channels: Global number of pub/sub channels with client subscriptions
• pubsub_patterns: Global number of pub/sub pattern with client subscriptions
• latest_fork_usec: Duration of the latest fork operation in microseconds

Here is the meaning of all fields in the replication section:

• role: Value is "master" if the instance is slave of no one, or "slave" if the instance is enslaved to a master. Note that a slave can be master of another slave (daisy chaining).

If the instance is a slave, these additional fields are provided:

• master_host: Host or IP address of the master
• master_port: Master listening TCP port
• master_link_status: Status of the link (up/down)
• master_last_io_seconds_ago: Number of seconds since the last interaction with master
• master_sync_in_progress: Indicate the master is SYNCing to the slave

If a SYNC operation is on-going, these additional fields are provided:

• master_sync_left_bytes: Number of bytes left before SYNCing is complete
• master_sync_last_io_seconds_ago: Number of seconds since last transfer I/O during a SYNC operation

If the link between master and slave is down, an additional field is provided:

• master_link_down_since_seconds: Number of seconds since the link is down

The following field is always provided:

• connected_slaves: Number of connected slaves

For each slave, the following line is added:

• slaveXXX: id, ip address, port, state

Here is the meaning of all fields in the cpu section:

• used_cpu_sys: System CPU consumed by the Redis server
• used_cpu_user:User CPU consumed by the Redis server
• used_cpu_sys_children: System CPU consumed by the background processes
• used_cpu_user_children: User CPU consumed by the background processes

The commandstats section provides statistics based on the command type, including the number of calls, the total CPU time consumed by these commands, and the average CPU consumed per command execution.

For each command type, the following line is added:

• cmdstat_XXX:calls=XXX,usec=XXX,usecpercall=XXX

The cluster section currently only contains a unique field:

• cluster_enabled: Indicate Redis cluster is enabled

The keyspace section provides statistics on the main dictionary of each database. The statistics are the number of keys, and the number of keys with an expiration.

For each database, the following line is added:

• dbXXX:keys=XXX,expires=XXX