How to log PostgreSQL queries?

Question

How to enable logging of all SQL executed by PostgreSQL 8.3?

Edited (more info) I changed these lines :

log_directory = 'pg_log'                    
log_filename = 'postgresql-%Y-%m-%d_%H%M%S.log'
log_statement = 'all'

And restart PostgreSQL service... but no log was created... I'm using Windows Server 2003.

Any ideas?

Answer 1

In your data/postgresql.conf file, change the log_statement setting to 'all'.

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Edit

Looking at your new information, I'd say there may be a few other settings to verify:

• make sure you have turned on the log_destination variable
• make sure you turn on the logging_collector
• also make sure that the log_directory directory already exists inside of the data directory, and that the postgres user can write to it.

Answer 2

Edit your /etc/postgresql/9.3/main/postgresql.conf, and change the lines as follows.

Note: If you didn't find the postgresql.conf file, then just type $locate postgresql.conf in a terminal

1. #log_directory = 'pg_log' to log_directory = 'pg_log'

2. #log_filename = 'postgresql-%Y-%m-%d_%H%M%S.log' to log_filename = 'postgresql-%Y-%m-%d_%H%M%S.log'

3. #log_statement = 'none' to log_statement = 'all'

4. #logging_collector = off to logging_collector = on

5. Optional: SELECT set_config('log_statement', 'all', true);

6. sudo /etc/init.d/postgresql restart or sudo service postgresql restart

7. Fire query in postgresql select 2+2

8. Find current log in /var/lib/pgsql/9.2/data/pg_log/

The log files tend to grow a lot over a time, and might kill your machine. For your safety, write a bash script that'll delete logs and restart postgresql server.

Thanks @paul , @Jarret Hardie , @Zoltán , @Rix Beck , @Latif Premani

Answer 3

FYI: The other solutions will only log statements from the default database—usually postgres—to log others; start with their solution; then:

ALTER DATABASE your_database_name
SET log_statement = 'all';

Ref: https://serverfault.com/a/376888 / log_statement

Answer 4

SELECT set_config('log_statement', 'all', true);

With a corresponding user right may use the query above after connect. This will affect logging until session ends.

Answer 5

You also need add these lines in PostgreSQL and restart the server:

log_directory = 'pg_log'                    
log_filename = 'postgresql-dateformat.log'
log_statement = 'all'
logging_collector = on

Answer 6

Set log_statement to all:

Error Reporting and Logging - log_statement

Answer 7

+1 to above answers. I use following config

log_line_prefix = '%t %c %u ' # time sessionid user
log_statement = 'all'

Answer 8

Just to have more details for CentOS 6.4 (Red Hat 4.4.7-3) running PostgreSQL 9.2, based on the instructions found on this web page:

1. Set (uncomment) log_statement = 'all' and log_min_error_statement = error in /var/lib/pgsql/9.2/data/postgresql.conf.
2. Reload the PostgreSQL configuration. For me, this was done by running /usr/pgsql-9.2/bin/pg_ctl reload -D /var/lib/pgsql/9.2/data/.
3. Find today's log in /var/lib/pgsql/9.2/data/pg_log/

Answer 9

There is an extension in postgresql for this. It's name is "pg_stat_statements". https://www.postgresql.org/docs/9.4/pgstatstatements.html

Basically you have to change postgresql.conf file a little bit:

shared_preload_libraries= 'pg_stat_statements'
pg_stat_statements.track = 'all'

Then you have to log in DB and run this command:

create extension pg_stat_statements;

It will create new view with name "pg_stat_statements". In this view you can see all the executed queries.

Answer 10

You should also set this parameter to log every statement:

log_min_duration_statement = 0

Answer 11

I was trying to set the log_statement in some postgres config file but in fact the file was not read by our postgres.

I confirmed that using the request :

select *
from pg_settings

[...]
log_statement   none # That was not the value i was expected for !!!

I use this way https://stackoverflow.com/a/41912295/2294168

command: postgres -c config_file=/etc/postgresql.conf