EDUCBA

EDUCBA

MENUMENU
  • Free Tutorials
  • Free Courses
  • Certification Courses
  • 360+ Courses All in One Bundle
  • Login
Home Data Science Data Science Tutorials PostgreSQL Tutorial PostgreSQL log
Secondary Sidebar
PostgreSQL Tutorial
  • Basic
    • What is PostgreSQL
    • PostgreSQL Features
    • How to Install PostgreSQL
    • PostgreSQL Versions
    • PostgreSQL Architecture
    • PostgreSQL GUI
    • Postgres Command-Line
    • PostgreSQL Variables
    • PostgreSQL Data Types
    • PostgreSQL NOT NULL
    • PostgreSQL Integer
    • PostgreSQL Boolean
    • PostgreSQL BIGINT
    • PostgreSQL NULLIF
    • PostgreSQL Administration
    • PostgreSQL Commands
    • PostgreSQL Operators
    • PostgreSQL IN Operator
    • Postgres like query
    • PostgreSQL encode
    • PostgreSQL Cheat Sheet
    • PostgreSQL List Databases
    • PostgreSQL Rename Database
  • Control Statement
    • PostgreSQL IF Statement
    • PostgreSQL if else
    • PostgreSQL CASE Statement
    • PostgreSQL LOOP
    • PostgreSQL For Loop
    • PostgreSQL While Loop
  • Joins
    • Joins in PostgreSQL
    • PostgreSQL Inner Join
    • PostgreSQL Outer Join
    • LEFT OUTER JOIN in PostgreSQL
    • PostgreSQL FULL OUTER JOIN
    • PostgreSQL LEFT JOIN
    • PostgreSQL Full Join
    • PostgreSQL Cross Join
    • PostgreSQL NATURAL JOIN
    • PostgreSQL UPDATE JOIN
  • Queries
    • PostgreSQL Queries
    • PostgreSQL INSERT INTO
    • PostgreSQL WHERE Clause
    • PostgreSQL WITH Clause
    • PostgreSQL ORDER BY
    • PostgreSQL ORDER BY Random
    • PostgreSQL ORDER BY DESC
    • PostgreSQL GROUP BY
    • PostgreSQL group_concat
    • PostgreSQL HAVING
    • PostgreSQL Recursive Query
  • Advanced
    • PostgreSQL Schema
    • Postgres List Schemas
    • PostgreSQL Drop Schema
    • PostgreSQL VARCHAR
    • Array in PostgreSQL
    • PostgreSQL DDL
    • PostgreSQL List Users
    • Postgres Default User
    • Postgres add user
    • PostgreSQL User Password
    • PostgreSQL log_statement
    • PostgreSQL repository
    • PostgreSQL shared_buffer
    • PostgreSQL String Functions
    • PostgreSQL Compare Strings
    • PostgreSQL Text Search
    • PostgreSQL TEXT
    • PostgreSQL String Array
    • PostgreSQL where in array
    • PostgreSQL Constraints
    • PostgreSQL UNIQUE Constraint
    • PostgreSQL CHECK Constraint
    • PostgreSQL INTERSECT
    • PostgreSQL Like
    • Cursors in PostgreSQL
    • PostgreSQL UNION ALL
    • Indexes in PostgreSQL
    • PostgreSQL Index Types
    • PostgreSQL REINDEX
    • PostgreSQL UNIQUE Index
    • PostgreSQL Clustered Index
    • PostgreSQL DROP INDEX
    • PostgreSQL DISTINCT
    • PostgreSQL FETCH
    • PostgreSQL RAISE EXCEPTION
    • PostgreSQL Auto Increment
    • Sequence in PostgreSQL
    • Wildcards in PostgreSQL
    • PostgreSQL Subquery
    • PostgreSQL Alias
    • PostgreSQL LIMIT
    • PostgreSQL Limit Offset
    • PostgreSQL LAG()
    • PostgreSQL Table
    • Postgres Show Tables
    • PostgreSQL Describe Table
    • PostgreSQL Lock Table
    • PostgreSQL ALTER TABLE
    • Postgres Rename Table
    • PostgreSQL List Tables
    • PostgreSQL TRUNCATE TABLE
    • PostgreSQL Table Partitioning
    • Postgres DROP Table
    • PostgreSQL Functions
    • PostgreSQL Math Functions
    • PostgreSQL Window Functions
    • Aggregate Functions in PostgreSQL
    • PostgreSQL Primary Key
    • Foreign Key in PostgreSQL
    • PostgreSQL Procedures
    • PostgreSQL Stored Procedures
    • PostgreSQL Views
    • PostgreSQL Materialized Views
    • Postgres Create View
    • PostgreSQL Triggers
    • PostgreSQL DROP TRIGGER
    • PostgreSQL Date Functions
    • PostgreSQL TO_DATE()
    • PostgreSQL datediff
    • PostgreSQL Timestamp
    • PostgreSQL CURRENT_TIMESTAMP()
    • PostgreSQL Notify
    • PostgreSQL LENGTH()
    • PostgreSQL blob
    • PostgreSQL Median
    • PostgreSQL kill query
    • PostgreSQL Formatter
    • PostgreSQL RANK()
    • PostgreSQL Select
    • PostgreSQL Average
    • PostgreSQL DATE_PART()
    • PostgreSQL EXECUTE
    • PostgreSQL COALESCE
    • PostgreSQL EXTRACT()
    • PostgreSQL Sort
    • PostgreSQL TO_CHAR
    • PostgreSQL Interval
    • PostgreSQL Number Types
    • PostgreSQL ROW_NUMBER
    • Alter Column in PostgreSQL
    • PostgreSQL Identity Column
    • PostgreSQL SPLIT_PART()
    • PostgreSQL CONCAT()
    • PostgreSQL replace
    • PostgreSQL TRIM()
    • PostgreSQL MAX
    • PostgreSQL DELETE
    • PostgreSQL Float
    • PostgreSQL OID
    • PostgreSQL log
    • PostgreSQL REGEXP_MATCHES()
    • PostgreSQL MD5 
    • PostgreSQL NOW()
    • PostgreSQL RANDOM
    • PostgreSQL round
    • PostgreSQL Trunc()
    • PostgreSQL TIME
    • PostgreSQL IS NULL
    • PostgreSQL CURRENT_TIME
    • PostgreSQL MOD()
    • Postgresql Count
    • PostgreSQL Datetime
    • PostgreSQL MIN()
    • PostgreSQL age()
    • PostgreSQL enum
    • PostgreSQL OR
    • PostgreSQL Wal
    • PostgreSQL NOT IN
    • PostgreSQL SET
    • PostgreSQL Current Date
    • PostgreSQL Compare Date
    • PostgreSQL SERIAL
    • PostgreSQL UUID
    • PostgreSQL Merge
    • PostgreSQL Database
    • PostgreSQL Clone Database
    • PostgreSQL Copy Database
    • PostgreSQL Show Databases
    • PostgreSQL Restore Database
    • PostgreSQL DROP DATABASE
    • PostgreSQL ALTER DATABASE
    • Postgres DROP Database
    • Postgres Dump Database
    • PostgreSQL OFFSET
    • PostgreSQL GRANT
    • PostgreSQL COMMIT
    • PostgreSQL ROLLUP
    • PostgreSQL JSON
    • EXPLAIN ANALYZE in PostgreSQL
    • PostgreSQL Temporary Table
    • PostgreSQL Show Tables
    • PostgreSQL cluster
    • PostgreSQL Replication
    • PostgreSQL Logical Replication
    • PostgreSQL flush privileges
    • PostgreSQL Tablespaces
    • CAST in PostgreSQL
    • PostgreSQL CTE
    • hstore in PostgreSQL
    • PostgreSQL Encryption
    • PostgreSQL DECODE()
    • PostgreSQL Vacuum
    • PostgreSQL EXCLUDE
    • Postgres Change Password
    • Postgres Delete Cascade
    • PostgreSQL EXCEPT
    • PostgreSQL Roles
    • PostgreSQL Link
    • PostgreSQL Partition
    • PostgreSQL column does not exist
    • PostgreSQL Log Queries
    • PostgreSQL escape single quote
    • PostgreSQL Query Optimization
    • PostgreSQL Character Varying
    • PostgreSQL Transaction
    • PostgreSQL Extensions
    • PostgreSQL Import CSV
    • PostgreSQL Client
    • PostgreSQL caching
    • PostgreSQL Incremental Backup
    • PostgreSQL JSON vs JSONNB
    • PostgreSQL JDBC Driver
    • PostgreSQL Interview Questions

PostgreSQL log

By Payal UdhaniPayal Udhani

PostgreSQL log

Introduction to PostgreSQL log

To find out the cause and debugging the issue that is use while executing a certain command, we need to check the logs, and for doing so, it is necessary to maintain the logs. PostgreSQL comes with a brilliant log management system whereby we are provided with multiple methods to store the logs and handle them. It s essential to know where what and when the logs should be maintained. For that, we have to set many parameters provided in Postgres to define our logging system’s behaviour and mention necessary information that will help in logging. In this article, we will learn about such parameters and logging in to PostgreSQL.

Severity Levels of Messages

While storing, you must be aware of the messages that may produce while executing commands and, depending on the severity, decide what kind of logs you want to maintain and store. The below table shows the severity levels of messages in decreasing order. That means panic is the most severe one, while debug1 to debug5 is developer-defined and has the lowest severity.

Start Your Free Data Science Course

Hadoop, Data Science, Statistics & others

Level of Severity Use of the message Logs in event Logs in system
PANIC It is the most critical one and reports an error that leads to closing and abortion of all the database sessions. ERROR CRIT
FATAL It is the error that results in closing and abortion of the current database session. ERROR ERR
LOG It helps in logging the information that will be helpful in administration, such as checkpoint activity. INFORMATION INFO
ERROR Only the current command is aborted when the error occurs while executing it. ERROR WARNING
WARNING It provides us with info about the things that might result in the error to take precautions earlier, such as when a commit is being done outside the transaction block. WARNING NOTICE
NOTICE It makes us aware of the information that will prove useful as the user, such as when long identifiers are truncated. INFORMATION NOTICE
INFO When the user explicitly demands certain kinds of information, it is used to display in INFO. For example, when VERBOSE is used while VACUUM or ANALYZE, then information is displayed. INFORMATION INFO
DEBUG1 to DEBUG5 It helps in providing additional information that the developer wants to give. INFORMATION DEBUG

Parameters Related to Logging in PostgreSQL

The parameters can be set from the postgresql.conf file or on the server command line. Some of the parameters that are used for the log management system are displayed below:

1. Parameter log_destination(string)

PostgreSQL, a log management system, allows us to store the logs in many ways, such as stderr, csvlog, event logging(only in windows) and Syslog. For example, if we set this parameter to csvlog, then the logs are stored in a comma-separated format. This parameter allows us to mention where the logs should be stored, and we can mention multiple parameters in comma-separated format. The default value of this parameter id stderr that is most often used.

2. Parameter logging_collector(boolean)

Logging in PostgreSQL is enabled if and only if this parameter is set to the true and logging collector is running. Logging collector works in the background to collect all the logs that are being sent to stderr that is standard error stream and redirect them to the file destination of log files. Some messages cannot be printed on the console; that’s why this method is preferred over Syslog. For example – while doing scriptings, the archieve_command() that is used does not display logs on the console when an error occurs while executing it.

3. Parameter log_directory(string)

This parameter determines where the log files should be created if the log collector is enabled. By default, this parameter has the value as pg_log and can contain an absolute or relative path to the cluster database’s location.

4. Parameter log_filename(string)

This parameter determines the name of the files that will be created for logging purposes. This field is time-varying and should be mentioned along with escape sequences %-escapes.

5. client_min_messages(enum)

This parameter defines the level up to the messages that should be sent to the client, and the sequence of the level considered here is not as mentioned above. It is PANIC, FATAL, INFO, ERROR, WARNING, NOTICE, LOG, DEBUG1, DEBUG2, DEBUG3, DEBUG4 AND DEBUG5. The default value of this parameter is set to NOTICE. Hence, all the messages previous to INFO will be sent to the client by default.

6. Parameter log_min_messages(enum)

This parameter defines the level up to the messages that should be written to server logs, and the sequence of the level considered here is not as mentioned above. It is PANIC, FATAL, LOG, ERROR, WARNING, NOTICE, INFO, DEBUG1, DEBUG2, DEBUG3, DEBUG4 AND DEBUG5. The default value of this parameter is set to NOTICE. Hence, all the messages previous to INFO will be written to server logs by default.

7. Parameter log_min_error_statement(enum)

This parameter defines the level up to the messages that should be logged, and the sequence of the level considered here is not as mentioned above. It is PANIC, FATAL, LOG, ERROR, WARNING, NOTICE, INFO, DEBUG1, DEBUG2, DEBUG3, DEBUG4 AND DEBUG5. The default value of this parameter is set to NOTICE. Hence, all the messages previous to INFO will be logged by default.

8. application_name(string)

The name of the application is less than 64 characters and can be displayed in the view named pg_stat_activity and is also included in the CSV logs that are maintained and can be included in other logs. Note that this application name should only contain ASCII characters that are printable; otherwise, those characters will be replaced with a question mark(?).

9. Parameter log_checkpoints(boolean)

If this parameter is set to true, then checkpoints and restart points will also be logged in server logs.

Conclusion – PostgreSQL log

We can use the log management system provided in PostgreSQL for debugging the issues, finding out the causes and improving the database operations efficiency, and maintaining the logs for future reference. We can set different parameters to define the logging behaviour and pattern and mention what things should be logged when the logging should be enabled and where the logs should be stored that are generated.

Recommended Articles

This is a guide to the PostgreSQL log. Here we discuss the Introduction to PostgreSQL log and its Severity Levels of Messages and different Parameters Related to Logging. You can also go through our suggested articles to learn more –

  1. MySQL Operators
  2. MySQL String functions
  3. MySQL vs SQLite
  4. PostgreSQL Auto Increment
Popular Course in this category
PostgreSQL Course (2 Courses, 1 Project)
  2 Online Courses |  1 Hands-on Project |  7+ Hours |  Verifiable Certificate of Completion
4.5
Price

View Course
Primary Sidebar
Footer
About Us
  • Blog
  • Who is EDUCBA?
  • Sign Up
  • Live Classes
  • Corporate Training
  • Certificate from Top Institutions
  • Contact Us
  • Verifiable Certificate
  • Reviews
  • Terms and Conditions
  • Privacy Policy
  •  
Apps
  • iPhone & iPad
  • Android
Resources
  • Free Courses
  • Database Management
  • Machine Learning
  • All Tutorials
Certification Courses
  • All Courses
  • Data Science Course - All in One Bundle
  • Machine Learning Course
  • Hadoop Certification Training
  • Cloud Computing Training Course
  • R Programming Course
  • AWS Training Course
  • SAS Training Course

ISO 10004:2018 & ISO 9001:2015 Certified

© 2023 - EDUCBA. ALL RIGHTS RESERVED. THE CERTIFICATION NAMES ARE THE TRADEMARKS OF THEIR RESPECTIVE OWNERS.

EDUCBA
Free Data Science Course

Hadoop, Data Science, Statistics & others

By continuing above step, you agree to our Terms of Use and Privacy Policy.
*Please provide your correct email id. Login details for this Free course will be emailed to you
EDUCBA

*Please provide your correct email id. Login details for this Free course will be emailed to you

Let’s Get Started

By signing up, you agree to our Terms of Use and Privacy Policy.

EDUCBA

*Please provide your correct email id. Login details for this Free course will be emailed to you
EDUCBA

*Please provide your correct email id. Login details for this Free course will be emailed to you
EDUCBA Login

Forgot Password?

By signing up, you agree to our Terms of Use and Privacy Policy.

This website or its third-party tools use cookies, which are necessary to its functioning and required to achieve the purposes illustrated in the cookie policy. By closing this banner, scrolling this page, clicking a link or continuing to browse otherwise, you agree to our Privacy Policy

Loading . . .
Quiz
Question:

Answer:

Quiz Result
Total QuestionsCorrect AnswersWrong AnswersPercentage

Explore 1000+ varieties of Mock tests View more