Configuration flags

FerretDB provides numerous configuration flags you can customize to suit your needs and environment. You can always see the complete list by using --help flag. To make user experience cloud native, every flag has its environment variable equivalent. There is no configuration file.

info

Some default values are overridden in our Docker image.

General

Interfaces

Backend handlers

PostgreSQL

PostgreSQL backend can be enabled by --handler=pg flag or FERRETDB_HANDLER=pg environment variable.

FerretDB uses pgx v5 library for connecting to PostgreSQL. Supported URL parameters are documented there:

• https://pkg.go.dev/github.com/jackc/pgx/v5/pgconn#ParseConfig
• https://pkg.go.dev/github.com/jackc/pgx/v5#ParseConfig
• https://pkg.go.dev/github.com/jackc/pgx/v5/pgxpool#ParseConfig

Additionally:

• pool_max_conns parameter is set to 50 if it is unset in the URL;
• application_name is always set to “FerretDB”;
• timezone is always set to “UTC”.

SQLite

SQLite backend can be enabled by --handler=sqlite flag or FERRETDB_HANDLER=sqlite environment variable.

FerretDB uses modernc.org/sqlite library for accessing SQLite database files. Supported URL parameters are documented there:

• https://www.sqlite.org/uri.html
• https://pkg.go.dev/modernc.org/sqlite#Driver.Open
• https://www.sqlite.org/pragma.html

Additionally:

• _pragma=auto_vacuum(none) parameter is set if that PRAGMA is not present;
• _pragma=busy_timeout(10000) parameter is set if that PRAGMA is not present;
• _pragma=journal_mode(wal) parameter is set if that PRAGMA is not present.

One difference is that URI should point to the existing directory (with absolute or relative path), not to a single database file. That allows FerretDB to work with multiple databases.

In-memory SQLite databases are fully supported. In that case, the URI should still point to the existing directory (that will be unused). For example: file:./?mode=memory.

Miscellaneous