The MEMORY STATS command returns an Array reply about the memory usage of the server.

The information about memory usage is provided as metrics and their respective values. The following metrics are reported:

  • peak.allocated: Peak memory consumed by Redis in bytes (see INFO's used_memory_peak)
  • total.allocated: Total number of bytes allocated by Redis using its allocator (see INFO's used_memory)
  • startup.allocated: Initial amount of memory consumed by Redis at startup in bytes (see INFO's used_memory_startup)
  • replication.backlog: Size in bytes of the replication backlog (see INFO's repl_backlog_active)
  • clients.slaves: The total size in bytes of all replicas overheads (output and query buffers, connection contexts)
  • clients.normal: The total size in bytes of all clients overheads (output and query buffers, connection contexts)
  • aof.buffer: The summed size in bytes of the current and rewrite AOF buffers (see INFO's aof_buffer_length and aof_rewrite_buffer_length, respectively)
  • lua.caches: the summed size in bytes of the overheads of the Lua scripts' caches
  • dbXXX: For each of the server's databases, the overheads of the main and expiry dictionaries (overhead.hashtable.main and overhead.hashtable.expires, respectively) are reported in bytes
  • overhead.total: The sum of all overheads, i.e. startup.allocated, replication.backlog, clients.slaves, clients.normal, aof.buffer and those of the internal data structures that are used in managing the Redis keyspace (see INFO's used_memory_overhead)
  • keys.count: The total number of keys stored across all databases in the server
  • keys.bytes-per-key: The ratio between net memory usage (total.allocated minus startup.allocated) and keys.count
  • dataset.bytes: The size in bytes of the dataset, i.e. overhead.total subtracted from total.allocated (see INFO's used_memory_dataset)
  • dataset.percentage: The percentage of dataset.bytes out of the net memory usage
  • peak.percentage: The percentage of peak.allocated out of total.allocated
  • fragmentation: See INFO's mem_fragmentation_ratio

Return value

Array reply: nested list of memory usage metrics and their values

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.

© 2009–2020 Salvatore Sanfilippo
Licensed under the Creative Commons Attribution-ShareAlike License 4.0.