PostgreSQL Client Connection Settings: Complete Guide to pg_settings Query

calendar Sep 2, 2025 / · 4 min read · postgresql database-administration sql-queries configuration client-connections system-views database-management performance-tuning  ·
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PostgreSQL Client Connection Settings: Complete Guide to pg_settings Query

This PostgreSQL query provides a comprehensive view of client connection default settings by querying the pg_settings system view, allowing database administrators to analyze and understand configuration parameters that affect client behavior.

Purpose and Overview

The query retrieves essential configuration parameters related to client connection defaults from PostgreSQL's pg_settings view. This system view contains all configuration parameters currently loaded by the PostgreSQL server, making it invaluable for database administration and troubleshooting connection-related issues.

Code Breakdown

 1SELECT
 2    name,
 3    setting,
 4    -- category,
 5    vartype,
 6    short_desc,
 7    enumvals,
 8    source,
 9    min_val,
10    max_val,
11    boot_val,
12    reset_val,
13    -- not available on PostgreSQL < 9.5
14    pending_restart
15FROM
16    pg_settings
17WHERE
18    -- Client Connection Defaults / Statement Behavior
19    -- Client Connection Defaults / Locale and Formatting
20    -- Client Connection Defaults / Other Defaults
21    -- Client Connection Defaults / Shared Library Preloading
22    category ILIKE '%Client Connection Defaults%';

Column Explanations

Core Information Columns:

  • name: The configuration parameter name
  • setting: The current value of the parameter
  • vartype: The data type of the parameter (bool, integer, string, etc.)
  • short_desc: A brief description of what the parameter controls

Value Range and Validation:

  • enumvals: Valid values for enumeration parameters
  • min_val: Minimum allowed value for numeric parameters
  • max_val: Maximum allowed value for numeric parameters

Configuration Source and State:

  • source: How the parameter was set (default, configuration file, command line, etc.)
  • boot_val: The default value at server startup
  • reset_val: The value to use when resetting the parameter
  • pending_restart: Whether a server restart is needed for changes to take effect

Filter Criteria

The WHERE clause uses ILIKE '%Client Connection Defaults%' to filter parameters specifically related to client connection defaults, which include:

  • Statement Behavior: Parameters affecting SQL statement execution
  • Locale and Formatting: Settings for date/time formatting and localization
  • Other Defaults: Miscellaneous client connection parameters
  • Shared Library Preloading: Library loading configurations for client sessions

Key Insights and Use Cases

Database Administration

This query is particularly useful for database administrators who need to:

  • Audit current client connection configurations
  • Troubleshoot connection-related issues
  • Document server configuration for compliance
  • Compare settings across different PostgreSQL instances

Performance Analysis

Understanding client connection defaults helps identify potential performance bottlenecks related to:

  • Connection pooling configurations
  • Statement timeout settings
  • Memory allocation for client sessions
  • Character encoding and locale settings

Security Configuration

Client connection defaults often include security-related parameters that control:

  • Authentication timeouts
  • SSL/TLS connection requirements
  • Default privileges for new connections
  • Session-level security policies

Common Parameters Retrieved

When executing this query, you'll typically see parameters such as:

  • default_transaction_isolation: Default isolation level for transactions
  • timezone: Default timezone for client sessions
  • datestyle: Format for date/time display
  • client_encoding: Character encoding for client connections
  • search_path: Default schema search path
  • statement_timeout: Maximum execution time for statements

Implementation Notes

PostgreSQL Version Compatibility

The pending_restart column is only available in PostgreSQL 9.5 and later versions. For earlier versions, you should comment out or remove this column from the SELECT list to avoid errors.

Performance Considerations

The pg_settings view is a system view that reads configuration directly from memory, making it very fast to query. However, for automated monitoring, consider caching results as configuration parameters rarely change during normal operations.

Practical Applications

Configuration Auditing

Use this query as part of regular configuration audits to ensure client connection defaults meet organizational standards and security policies.

Troubleshooting Guide

When investigating client connection issues, this query provides immediate visibility into relevant configuration parameters without needing to examine multiple configuration files.

References

PostgreSQL Official Documentation - pg_settings - This provides comprehensive documentation for the pg_settings system view, which offers access to run-time parameters of the server and serves as an alternative interface to the SHOW and SET commands.

PostgreSQL Configuration Parameters - Server Configuration - This is the complete reference for all PostgreSQL configuration options, covering server configuration parameters in detail. It describes how to interact with configuration parameters and discusses each parameter comprehensively.

PostgreSQL Administration Guide - Server Administration - This covers server administration topics including installation, configuration of the server, management of users and databases, and other administrative tasks.

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