330-pg_bgwriter.yml

##
# SYNOPSIS
#       pg_bgwriter_*
#
# DESCRIPTION
#       PostgreSQL background writer metrics
#
# OPTIONS
#       Tags       [cluster]
#       TTL        10
#       Priority   0
#       Timeout    100ms
#       Fatal      false
#       Version    90400 ~ higher
#       Source     330-pg_bgwriter.yml
#
# METRICS
#       checkpoints_timed (COUNTER)
#           Number of scheduled checkpoints that have been performed
#       checkpoints_req (COUNTER)
#           Number of requested checkpoints that have been performed
#       checkpoint_write_time (COUNTER)
#           Total amount of time that has been spent in the portion of checkpoint processing where files are written to disk, in seconds
#       checkpoint_sync_time (COUNTER)
#           Total amount of time that has been spent in the portion of checkpoint processing where files are synchronized to disk, in seconds
#       buffers_checkpoint (COUNTER)
#           Number of buffers written during checkpoints
#       buffers_clean (COUNTER)
#           Number of buffers written by the background writer
#       buffers_backend (COUNTER)
#           Number of buffers written directly by a backend
#       maxwritten_clean (COUNTER)
#           Number of times the background writer stopped a cleaning scan because it had written too many buffers
#       buffers_backend_fsync (COUNTER)
#           Number of times a backend had to execute its own fsync call
#       buffers_alloc (COUNTER)
#           Number of buffers allocated
#       reset_time (COUNTER)
#           Time at which bgwriter statistics were last reset
#
pg_bgwriter_17:
  name: pg_bgwriter
  desc: "PostgreSQL background writer metrics PG 17+"
  # https://pgpedia.info/p/pg_stat_bgwriter.html
  query: SELECT buffers_clean, maxwritten_clean, buffers_alloc, extract(EPOCH FROM stats_reset) AS reset_time FROM pg_stat_bgwriter;

  ttl: 10
  min_version: 170000
  tags:
    - cluster
  metrics:
    - buffers_clean:
        usage: COUNTER
        description: Number of buffers written by the background writer
    - maxwritten_clean:
        usage: COUNTER
        description: Number of times the background writer stopped a cleaning scan because it had written too many buffers
    - buffers_alloc:
        usage: COUNTER
        description: Number of buffers allocated
    - reset_time:
        usage: COUNTER
        description: Time at which bgwriter statistics were last reset


pg_bgwriter_16:
  name: pg_bgwriter
  desc: "PostgreSQL background writer metrics (PG17-)"
  # https://pgpedia.info/p/pg_stat_bgwriter.html
  query: SELECT checkpoints_timed, checkpoints_req, checkpoint_write_time, checkpoint_sync_time, buffers_checkpoint, buffers_clean, buffers_backend, maxwritten_clean, buffers_backend_fsync, buffers_alloc, extract(EPOCH FROM stats_reset) AS reset_time FROM pg_stat_bgwriter;

  ttl: 10
  min_version: 090400
  max_version: 170000
  tags:
    - cluster

  metrics:
    - checkpoints_timed:
        usage: COUNTER
        description: Number of scheduled checkpoints that have been performed
    - checkpoints_req:
        usage: COUNTER
        description: Number of requested checkpoints that have been performed
    - checkpoint_write_time:
        usage: COUNTER
        scale: 1e-3
        description: Total amount of time that has been spent in the portion of checkpoint processing where files are written to disk, in seconds
    - checkpoint_sync_time:
        usage: COUNTER
        scale: 1e-3
        description: Total amount of time that has been spent in the portion of checkpoint processing where files are synchronized to disk, in seconds
    - buffers_checkpoint:
        usage: COUNTER
        description: Number of buffers written during checkpoints
    - buffers_clean:
        usage: COUNTER
        description: Number of buffers written by the background writer
    - buffers_backend:
        usage: COUNTER
        description: Number of buffers written directly by a backend
    - maxwritten_clean:
        usage: COUNTER
        description: Number of times the background writer stopped a cleaning scan because it had written too many buffers
    - buffers_backend_fsync:
        usage: COUNTER
        description: Number of times a backend had to execute its own fsync call
        # Number of times a backend had to execute its own fsync call (normally the background writer handles those even when the backend does its own write)
    - buffers_alloc:
        usage: COUNTER
        description: Number of buffers allocated
    - reset_time:
        usage: COUNTER
        description: Time at which bgwriter statistics were last reset