LATENCY

Since 1.1.0Observability

Syntax

LATENCY
  • Flags: admin
  • ACL categories: @admin, @dangerous, @server, @slow
  • Arity: -2

The latency monitor: it records, for each kind of event, the times it took longer than latency-monitor-threshold milliseconds, which is 0, off, by default. Events include command (a slow command), fast-command (a slow O(1) or O(log N) one), and expire-cycle (expiring keys in the background). See its subcommands.

Subcommands

  • LATENCY DOCTOR: Reports, in words, the events whose latest samples were slow: as warnings from 100 ms, as critical from 500 ms.
  • LATENCY GRAPH: Draws an event's samples as a small text chart, with the highest and lowest.
  • LATENCY HELP: Lists the LATENCY subcommands and what each does.
  • LATENCY HISTOGRAM: Returns, for each command named, or every command called, its number of calls and how many of them took less than each power of two of microseconds.
  • LATENCY HISTORY: Returns an event's samples, oldest first, each the Unix time and the milliseconds; an empty array for an event with none.
  • LATENCY LATEST: Returns each event's latest sample: the event, the Unix time, and the milliseconds it took.
  • LATENCY RESET: Clears the samples of every event, or of the events named.