moonfire-nvr/guide/schema.md

Moonfire NVR Schema Guide

This document has notes about the Moonfire NVR storage schema. As described in README.md, this consists of two kinds of state:

• a SQLite database, typically <1 GiB. It should be stored on flash if available.
• the "sample file directory", which holds the actual samples/frames of H.264 video. This should be quite large and typically is stored on a hard drive.

Upgrading

The database schema includes a version number to quickly identify if a the database is compatible with a particular version of the software. Some software upgrades will require you to upgrade the database.

Unversioned to version 0

Early versions of Moonfire NVR did not include the version information in the schema. You can manually add this information to your schema using the sqlite3 commandline. This process is backward compatible, meaning that software versions that accept an unversioned database will also accept a version 0 database.

Version 0 makes two changes:

* schema versioning, as described above.
* adding a column (`video_sync_samples`) to a database index to speed up
  certain operations.

First ensure Moonfire NVR is not running; if you are using systemd with the service name moonfire-nvr, you can do this as follows:

$ sudo systemctl stop moonfire-nvr

The service takes a moment to shut down; wait until the following command reports that it is not running:

$ sudo systemctl status moonfire-nvr

Then use sqlite3 to manually edit the database. The default path is /var/lib/moonfire-nvr/db/db; if you've specified a different --db_dir, use that directory with a suffix of /db.

$ sudo -u moonfire-nvr sqlite3 /var/lib/moonfire-nvr/db/db sqlite3>

At the prompt, run the following commands:

begin transaction;

create table version (
  id integer primary key,
  unix_time integer not null,
  notes text
);

insert into version values (0, cast(strftime('%s', 'now') as int),
                            'manual upgrade to version 0');

drop index recording_cover;

create index recording_cover on recording (
  camera_id,
  start_time_90k,
  duration_90k,
  video_samples,
  video_sample_entry_id,
  sample_file_bytes
);

commit transaction;

When you are done, you can restart the service:

$ sudo systemctl start moonfire-nvr