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diff --git a/iredis/data/commands/info.md b/iredis/data/commands/info.md new file mode 100644 index 0000000..8dcebc1 --- /dev/null +++ b/iredis/data/commands/info.md @@ -0,0 +1,335 @@ +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/replica replication information +- `cpu`: CPU consumption statistics +- `commandstats`: Redis command statistics +- `cluster`: Redis Cluster section +- `modules`: Modules section +- `keyspace`: Database related statistics +- `modules`: Module related sections + +It can also take the following values: + +- `all`: Return all sections (excluding module generated ones) +- `default`: Return only the default set of sections +- `everything`: Includes `all` and `modules` + +When no parameter is provided, the `default` option is assumed. + +@return + +@bulk-string-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 of `field:value` terminated by `\r\n`. + +```cli +INFO +``` + +## 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 +- `redis_build_id`: The build id +- `redis_mode`: The server's mode ("standalone", "sentinel" or "cluster") +- `os`: Operating system hosting the Redis server +- `arch_bits`: Architecture (32 or 64 bits) +- `multiplexing_api`: Event loop mechanism used by Redis +- `atomicvar_api`: Atomicvar API 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 +- `hz`: The server's current frequency setting +- `configured_hz`: The server's configured frequency setting +- `lru_clock`: Clock incrementing every minute, for LRU management +- `executable`: The path to the server's executable +- `config_file`: The path to the config file + +Here is the meaning of all fields in the **clients** section: + +- `connected_clients`: Number of client connections (excluding connections from + replicas) +- `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`, `BZPOPMIN`, `BZPOPMAX`) +- `tracking_clients`: Number of clients being tracked (`CLIENT TRACKING`) +- `clients_in_timeout_table`: Number of clients in the clients timeout table + +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 as + [**tcmalloc**][hcgcpgp]) +- `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(1)` and `ps(1)` +- `used_memory_rss_human`: Human readable representation of previous value +- `used_memory_peak`: Peak memory consumed by Redis (in bytes) +- `used_memory_peak_human`: Human readable representation of previous value +- `used_memory_peak_perc`: The percentage of `used_memory_peak` out of + `used_memory` +- `used_memory_overhead`: The sum in bytes of all overheads that the server + allocated for managing its internal data structures +- `used_memory_startup`: Initial amount of memory consumed by Redis at startup + in bytes +- `used_memory_dataset`: The size in bytes of the dataset + (`used_memory_overhead` subtracted from `used_memory`) +- `used_memory_dataset_perc`: The percentage of `used_memory_dataset` out of the + net memory usage (`used_memory` minus `used_memory_startup`) +- `total_system_memory`: The total amount of memory that the Redis host has +- `total_system_memory_human`: Human readable representation of previous value +- `used_memory_lua`: Number of bytes used by the Lua engine +- `used_memory_lua_human`: Human readable representation of previous value +- `used_memory_scripts`: Number of bytes used by cached Lua scripts +- `used_memory_scripts_human`: Human readable representation of previous value +- `maxmemory`: The value of the `maxmemory` configuration directive +- `maxmemory_human`: Human readable representation of previous value +- `maxmemory_policy`: The value of the `maxmemory-policy` configuration + directive +- `mem_fragmentation_ratio`: Ratio between `used_memory_rss` and `used_memory` +- `mem_allocator`: Memory allocator, chosen at compile time +- `active_defrag_running`: Flag indicating if active defragmentation is active +- `lazyfree_pending_objects`: The number of objects waiting to be freed (as a + result of calling `UNLINK`, or `FLUSHDB` and `FLUSHALL` with the **ASYNC** + option) + +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. + +Additional introspective information about the server's memory can be obtained +by referring to the `MEMORY STATS` command and the `MEMORY DOCTOR`. + +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 +- `rdb_last_cow_size`: The size in bytes of copy-on-write allocations during the + last RDB save operation +- `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 +- `aof_last_write_status`: Status of the last write operation to the AOF +- `aof_last_cow_size`: The size in bytes of copy-on-write allocations during the + last AOF rewrite operation +- `module_fork_in_progress`: Flag indicating a module fork is on-going +- `module_fork_last_cow_size`: The size in bytes of copy-on-write allocations + during the last module fork operation + +`rdb_changes_since_last_save` refers to the number of operations that produced +some kind of changes in the dataset since the last time either `SAVE` 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 +- `total_net_input_bytes`: The total number of bytes read from the network +- `total_net_output_bytes`: The total number of bytes written to the network +- `instantaneous_input_kbps`: The network's read rate per second in KB/sec +- `instantaneous_output_kbps`: The network's write rate per second in KB/sec +- `rejected_connections`: Number of connections rejected because of `maxclients` + limit +- `sync_full`: The number of full resyncs with replicas +- `sync_partial_ok`: The number of accepted partial resync requests +- `sync_partial_err`: The number of denied partial resync requests +- `expired_keys`: Total number of key expiration events +- `expired_stale_perc`: The percentage of keys probably expired +- `expired_time_cap_reached_count`: The count of times that active expiry cycles + have stopped early +- `expire_cycle_cpu_milliseconds`: The cumulative amount of time spend on active + expiry cycles +- `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 +- `migrate_cached_sockets`: The number of sockets open for `MIGRATE` purposes +- `slave_expires_tracked_keys`: The number of keys tracked for expiry purposes + (applicable only to writable replicas) +- `active_defrag_hits`: Number of value reallocations performed by active the + defragmentation process +- `active_defrag_misses`: Number of aborted value reallocations started by the + active defragmentation process +- `active_defrag_key_hits`: Number of keys that were actively defragmented +- `active_defrag_key_misses`: Number of keys that were skipped by the active + defragmentation process +- `tracking_total_keys`: Number of keys being tracked by the server +- `tracking_total_items`: Number of items, that is the sum of clients number for + each key, that are being tracked +- `tracking_total_prefixes`: Number of tracked prefixes in server's prefix table + (only applicable for broadcast mode) +- `unexpected_error_replies`: Number of unexpected error replies, that are types + of errors from an AOF load or replication + +Here is the meaning of all fields in the **replication** section: + +- `role`: Value is "master" if the instance is replica of no one, or "slave" if + the instance is a replica of some master instance. Note that a replica can be + master of another replica (chained replication). +- `master_replid`: The replication ID of the Redis server. +- `master_replid2`: The secondary replication ID, used for PSYNC after a + failover. +- `master_repl_offset`: The server's current replication offset +- `second_repl_offset`: The offset up to which replication IDs are accepted +- `repl_backlog_active`: Flag indicating replication backlog is active +- `repl_backlog_size`: Total size in bytes of the replication backlog buffer +- `repl_backlog_first_byte_offset`: The master offset of the replication backlog + buffer +- `repl_backlog_histlen`: Size in bytes of the data in the replication backlog + buffer + +If the instance is a replica, 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 replica +- `slave_repl_offset`: The replication offset of the replica instance +- `slave_priority`: The priority of the instance as a candidate for failover +- `slave_read_only`: Flag indicating if the replica is read-only + +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 replica 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 replicas + +If the server is configured with the `min-slaves-to-write` (or starting with +Redis 5 with the `min-replicas-to-write`) directive, an additional field is +provided: + +- `min_slaves_good_slaves`: Number of replicas currently considered good + +For each replica, the following line is added: + +- `slaveXXX`: id, IP address, port, state, offset, lag + +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,usec_per_call=XXX` + +The **cluster** section currently only contains a unique field: + +- `cluster_enabled`: Indicate Redis cluster is enabled + +The **modules** section contains additional information about loaded modules if +the modules provide it. The field part of properties lines in this section is +always prefixed with the module's name. + +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` + +[hcgcpgp]: http://code.google.com/p/google-perftools/ + +**A note about the word slave used in this man page**: Starting with Redis 5, if +not for backward compatibility, the Redis project no longer uses the word slave. +Unfortunately in this command the word slave is part of the protocol, so we'll +be able to remove such occurrences only when this API will be naturally +deprecated. + +**Modules generated sections**: Starting with Redis 6, modules can inject their +info into the `INFO` command, these are excluded by default even when the `all` +argument is provided (it will include a list of loaded modules but not their +generated info fields). To get these you must use either the `modules` argument +or `everything`., |