Prefill

Create prefill configuration

Prefill is instrumented by the pgagroal_databases.conf configuration file, where you need to list databases, usernames, and limits. Every username/database pair has to be specified on a separated line.

The limits are assumed as:

• max number of allowed connections for that username/database
• initial number of connections, that is the effective prefill;
• minimum number of connections to always keep open for the pair username/database.

Assuming you want to configure the prefill for the mydb database with the myuser username, you have to edit the file /etc/pgagroal/pgagroal_databases.conf with your editor of choice or using cat from the command line, as follows:

cd /etc/pgagroal
cat > pgagroal_databases.conf
mydb   myuser   2   1   0

and press Ctrl-d to save the file.

This will create a configuration where mydb will have a maximum connection size of 2, an initial connection size of 1 and a minimum connection size of 0 for the myuser user.

The file must be owned by the operating system user pgagroal.

The max_size value is mandatory, while the initial_size and min_size are optional and if not explicitly set are assumed to be 0. See the pgagroal_databases.conf file documentation for more details.

Restart pgagroal

In order to apply changes to the prefill configuration, you need to restart pgagroal. You can do so by stopping it and then re-launch the daemon, as pgagroal operating system user:

pgagroal-cli shutdown
pgagroal -d

Check the prefill

You can check the prefill by running, as the pgagroal operating system user, the status command:

pgagroal-cli status
Status:              Running
Active connections:  0
Total connections:   1
Max connections:     100

where the Total connections is set by the initial connection specified in the limit file.