Just so that it will be perfectly clear: the logs I have in mind are the ones for DBAs to read – with slow queries, errors, and other interesting information.
So, how does one find them?
Tag: configuration
Starting with Pg – where/how can I set configuration parameters?
Previously I wrote about locating config files.
The thing is – postgresql.conf is not the only place you can set your configuration in.
In here, I'll describe all the places that can be used, why do we even have more than one place, and finally – how to find out where given value comes from.
Continue reading Starting with Pg – where/how can I set configuration parameters?
Starting with Pg – where is the config?
Over the years I saw some people find themselves in position where they have to start dealing with PostgreSQL with minimal, or none, prior exposure. This leads to problems with seemingly easy tasks – how to change config? How to find stuff in logs?
So I decided to write some blogposts to be able to point such people to pre-made tutorials.
And I start today, with information on how to find PostgreSQL config files.
Waiting for PostgreSQL 12 – Integrate recovery.conf into postgresql.conf
On 25th of November 2018, Peter Eisentraut committed patch:
Integrate recovery.conf into postgresql.conf recovery.conf settings are now set in postgresql.conf (or other GUC sources). Currently, all the affected settings are PGC_POSTMASTER; this could be refined in the future case by case. Recovery is now initiated by a file recovery.signal. Standby mode is initiated by a file standby.signal. The standby_mode setting is gone. If a recovery.conf file is found, an error is issued. The trigger_file setting has been renamed to promote_trigger_file as part of the move. The documentation chapter "Recovery Configuration" has been integrated into "Server Configuration". pg_basebackup -R now appends settings to postgresql.auto.conf and creates a standby.signal file. Author: Fujii Masao Author: Simon Riggs Author: Abhijit Menon-Sen Author: Sergei Kornilov Discussion: https://www.postgresql.org/message-id/flat/@web3g.yandex.ru/
Continue reading Waiting for PostgreSQL 12 – Integrate recovery.conf into postgresql.conf
Waiting for 9.6 – Add new system view, pg_config
On 17th of February, Joe Conway committed patch:
Add new system view, pg_config Move and refactor the underlying code for the pg_config client application to src/common in support of sharing it with a new system information SRF called pg_config() which makes the same information available via SQL. Additionally wrap the SRF with a new system view, as called pg_config. Patch by me with extensive input and review by Michael Paquier and additional review by Alvaro Herrera.
Continue reading Waiting for 9.6 – Add new system view, pg_config
Waiting for 9.5 – Add pg_settings.pending_restart column
On 15th of May, Peter Eisentraut committed patch:
Add pg_settings.pending_restart column with input from David G. Johnston, Robert Haas, Michael Paquier
Continue reading Waiting for 9.5 – Add pg_settings.pending_restart column
Waiting for 9.5 – Replace checkpoint_segments with min_wal_size and max_wal_size.
On 23rd of February, Heikki Linnakangas committed patch:
Replace checkpoint_segments with min_wal_size and max_wal_size. Instead of having a single knob (checkpoint_segments) that both triggers checkpoints, and determines how many checkpoints to recycle, they are now separate concerns. There is still an internal variable called CheckpointSegments, which triggers checkpoints. But it no longer determines how many segments to recycle at a checkpoint. That is now auto-tuned by keeping a moving average of the distance between checkpoints (in bytes), and trying to keep that many segments in reserve. The advantage of this is that you can set max_wal_size very high, but the system won't actually consume that much space if there isn't any need for it. The min_wal_size sets a floor for that; you can effectively disable the auto-tuning behavior by setting min_wal_size equal to max_wal_size. The max_wal_size setting is now the actual target size of WAL at which a new checkpoint is triggered, instead of the distance between checkpoints. Previously, you could calculate the actual WAL usage with the formula "(2 + checkpoint_completion_target) * checkpoint_segments + 1". With this patch, you set the desired WAL usage with max_wal_size, and the system calculates the appropriate CheckpointSegments with the reverse of that formula. That's a lot more intuitive for administrators to set. Reviewed by Amit Kapila and Venkata Balaji N.
Continue reading Waiting for 9.5 – Replace checkpoint_segments with min_wal_size and max_wal_size.
Waiting for 9.4 – Add ALTER SYSTEM command to edit the server configuration file.
On 18th of December, Tatsuo Ishii committed patch:
Add ALTER SYSTEM command to edit the server configuration file. Patch contributed by Amit Kapila. Reviewed by Hari Babu, Masao Fujii, Boszormenyi Zoltan, Andres Freund, Greg Smith and others.
On the next day, Fujii Masao committed patch:
Add tab completion for ALTER SYSTEM SET in psql.
Continue reading Waiting for 9.4 – Add ALTER SYSTEM command to edit the server configuration file.
Write Ahead Log + Understanding postgresql.conf: checkpoint_segments, checkpoint_timeout, checkpoint_warning
Understanding postgresql.conf : work_mem
For todays post in Understanding postgresql.conf series, I chose work_mem parameter.