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logfmt

This Release
logfmt 1.0.0
Date
Status
Stable
Abstract
logfmt log collector
Description
Enable standard logfmt style log format with a single shared preload library.
Released By
bersace
License
PostgreSQL
Resources
Special Files
Tags

Extensions

logfmt 1.0.0

Documentation

CONTRIBUTING
Hacking

README

logfmt for PostgreSQL

Format PostgreSQL logs as logfmt.

logfmt is a log style designed by Heroku. It's a compact way of presenting untyped structured log, easier for human to read and for machine to marshal. logfmt is now a best practice in Grafana/Loki and kubernetes world.

ts=2023-05-25T10:01:50.992+0200 level=LOG message="checkpoint starting: time" ts=2023-05-25T10:01:50.992+0200 level=LOG message="checkpoint complete: wrote 15 buffers (0.1%); 0 WAL file(s) added, 0 removed, 0 recycled; write=1.215 s, sync=0.008 s, total=1.236 s; sync files=13, longest=0.005 s, average=0.001 s; distance=63 kB, estimate=63 kB; lsn=0/1CB7BA0, redo lsn=0/1CB7B68"

Build and Installation from Source

For now, logfmt is only available through git.

  • Get the source code using git.
  • Setup your PATH with pg_config for the target PostgreSQL version.
  • Type make to build.
  • Type make install to install.

logfmt is known to work with PostgreSQL 16beta1.

Enable logfmt

  • Add logfmt to shared_preload_libraries.
  • Restart PostgreSQL.

Parameter

The logfmt.application_context parameter allows you to set an application-centric tag to group log entries. For example, set it to the UUID of a web request or a background task.

Fields

logfmt has opininated field names based on regular logfmt fields and on elog and jsonlog PostgreSQL fields. logfmt respects log_error_verbosity parameter.

Terse fields:

  • application_name and application_context
  • dbname
  • level - Error severity.
  • message
  • pid - Postgres process identifier.
  • statement, statement.position
  • ts - Log timestamp with millisecond and timezone offset.
  • user

Default fields:

  • remote.host, remote.port
  • context
  • detail
  • hint
  • xid, vxid
  • internal.query, internal.position
  • backend_type
  • leader.pid
  • statement.qid - pg_stat_statement query ID.

Verbose fields:

  • backtrace
  • errcode - SQL error code.
  • location.file, location.line, location.func

Output order is hard coded.

About

logfmt is a PostgreSQL extension initiated by Dalibo.