How to tune PGroonga

Normally, you don't need to tune PGroonga because PGroonga works well by default.

But you need to tune PGroonga in some cases such as a case that you need to handle a very large database. PGroonga uses Groonga as backend. It means that you can apply tuning knowledge for Groonga to PGroonga. See also the Groonga tuning document to tune PGroonga.

Basic tuning

nofile

When you are inserting or updating huge amout of data using PGroonga, you might get following errors in your pgroonga.log.

SQLSTATE[58000]: <<Unknown error>>: 7 ERROR:  pgroonga: [insert] failed to set column value: system call error: Too many open files: [io][open] failed to open path: <base/121469/pgrn.00001C4>

PostgreSQL process that uses PGroonga needs to open many files but your system preferences are not allowing it. In order to solve this, you need to create a configuration file /etc/security/limits.d/postgresql.conf with the following content:

postgres soft nofile 65535
postgres hard nofile 65535

In this example, one PostgreSQL process can open up to 65535 files.

To calculate how many open files are sufficient, please refer to Groonga: Turning: The max number of open files per process

vm.overcommit_memory

When you are performing search using PGroonga, you might get following warning in your pgroonga.log.

vm.overcommit_memory kernel parameter should be 1: <0>: See INFO level log to resolve this

In order to prevent this warning from happening, you need to set vm.overcommit_memory kernel parameter to 1. To do this, you need to create a configuration file /etc/sysctl.d/groonga.conf that has the following content:

vm.overcommit_memory = 1

The configuration can be applied by restarting your system or run the following command:

sudo sysctl --system

See also

• Groonga: Tuning