Heroku PGSettings

Last updated March 27, 2026

Heroku Postgres Standard, Premium, Private, and Shield plans can manage database settings by configuring parameters via the pg:settings command.

$ heroku pg:settings postgresql-large-1234 -a example-app
=== postgresql-large-1234
auto-explain:                       false
auto-explain.log-analyze:           false
auto-explain.log-buffers:           false
auto-explain.log-format:            text
auto-explain.log-min-duration:      -1
auto-explain.log-nested-statements: false
auto-explain.log-triggers:          false
auto-explain.log-verbose:           false
data-connector-details-logs:        false
log-connections:                    true
log-lock-waits:                     true
log-min-duration-statement:         2000
log-min-error-statement:            error
log-statement:                      ddl
track-functions:                    none

Essential-tier plans use default settings that Heroku Postgres manages, which you can’t reconfigure.

log-lock-waits

log-lock-waits controls whether a log message is produced when a session waits longer than 1 second to acquire a lock. Long lock waits can cause performance issues.

The default value is on.

$ heroku pg:settings:log-lock-waits postgresql-large-1234 off -a example-app
log-lock-waits has been set to false for postgresql-large-1234.
When a deadlock is detected, no log message will be emitted in your application's logs.

log-min-duration-statement

log-min-duration-statement logs the duration of each completed statement if the statement ran for at least the specified number of milliseconds. A value of 0 logs every statement. A value of -1 disables logging. This setting helps you track down slow or unoptimized queries.

The default value is 2000 milliseconds or 2 seconds.

On a system with hundreds of queries executing every second, log files can grow quickly and affect database performance.

$ heroku pg:settings:log-min-duration-statement postgresql-large-1234 3000 -a example-app
log-min-duration-statement has been set to 3000 for postgresql-large-1234.

log-min-error-statement

log_min_error_statement controls whether the SQL statement that caused an error is logged based on the error’s severity. Use this setting to prevent logging SQL queries that contain sensitive information. The valid values for log_min_error_statement are:

  • error
  • log
  • fatal
  • panic

When you configure a severity level, the statement is logged for any errors of the specified severity or higher.

The default value is error. This setting logs the statement for errors with severity error, log, fatal, and panic.

$ heroku pg:settings:log-min-error-statement postgresql-large-1234 panic -a example-app
log-min-error-statement has been set to panic for postgresql-large-1234.
Logs only PANIC level messages.

log-statement

log-statement controls which normal SQL statements are logged. This setting can help you debug complex queries or audit queries made by your app or database users. Valid values for log-statement are:

  • none: Don’t log normal queries. Other logs still generate such as slow query logs, queries waiting in locks, and syntax errors
  • ddl: Log all data definition statements, such as CREATE, ALTER, and DROP.
  • mod: Log all statements from DDL and data-modifying statements such as INSERT, UPDATE, DELETE, TRUNCATE, and COPY.
  • all: Log all statements.

The default value is ddl.

$ heroku pg:settings:log-statement postgresql-large-1234 all -a example-app
log-statement has been set to all for postgresql-large-1234.

track-functions

track-functions controls which functions have their execution statistics tracked. These statistics can be found in the pg_stat_user_functions view. Valid values for track-functions are:

  • none: No function statistics are recorded.
  • pl: Procedural language function statistics are recorded (for example, PL/pgSQL functions).
  • all: All functions, including SQL and C language function statistics are recorded.

This default value is none.

$ heroku pg:settings:track-functions postgresql-large-1234 pl -a example-app
track-functions has been set to pl for postgresql-large-1234.
Track only procedural-language functions.

data-connector-details-logs

data-connector-details-logs controls whether detailed statistics for data connectors are emitted to the database logs when you use Streaming Data Connectors. See Heroku Postgres Metrics Logs for the list of metrics.

The default value is off.

$ heroku pg:settings:data-connector-details-logs postgresql-large-1234 on -a example-app
data-connector-details-logs has been set to on for postgresql-large-1234.

auto-explain

auto_explain logs query execution plans automatically without having to run EXPLAIN manually. auto_explain can help identify slow or expensive queries and understand how to optimize them. Enable auto_explain with:

$ heroku pg:settings:auto-explain postgresql-large-1234 on -a example-app

Enabling auto_explain can cause increased log volume and affect performance. Use it with caution and monitor your database performance. auto_explain enables the module for all future Heroku Postgres connections. Existing connections must reconnect before auto_explain logging takes effect.

The following settings tune auto_explain behavior. You must enable auto_explain to use these settings.

auto-explain:log-analyze

log-analyze runs EXPLAIN ANALYZE on all queries regardless if they’re logged or not. This setting can have a significant performance impact on your database so use with caution.

The default value is off.

$ heroku pg:settings:auto-explain:log-analyze postgresql-large-1234 on -a example-app

auto-explain:log-buffers

log-buffers is equivalent to the BUFFERS option of EXPLAIN. You can only use it when auto-explain:log-analyze is on.

The default value is off.

$ heroku pg:settings:auto-explain:log-buffers postgresql-large-1234 on -a example-app

auto-explain:log-format

log-format sets the output format for the EXPLAIN command. The valid values are:

  • text
  • xml
  • json
  • yaml

The default value is text.

$ heroku pg:settings:auto-explain:log-format postgresql-large-1234 json -a example-app

auto-explain:log-min-duration

log-min-duration sets the minimum log duration in milliseconds for a query to have its plan logged. A value of-1 disables all logging. A value of 0 logs all executed queries.

The default value is -1.

$ heroku pg:settings:auto-explain:log-min-duration postgresql-large-1234 200 -a example-app

auto-explain:log-nested-statements

log-nested-statements includes nested statements, such as from functions, to the execution plan’s log.

The default value is off.

$ heroku pg:settings:auto-explain:log-nested-statements postgresql-large-1234 on -a example-app

auto-explain:log-triggers

log-triggers includes trigger execution statistics in the execution plan’s logs.

The default value is off.

$ heroku pg:settings:auto-explain:log-triggers postgresql-large-1234 on -a example-app

auto-explain:log-verbose

log-verbose includes verbose details in the execution plan’s logs. This setting is equivalent to the VERBOSE option of EXPLAIN.

The default value is off.

$ heroku pg:settings:auto-explain:log-verbose postgresql-large-1234 on -a example-app