[mb-devel] Using NGS live feed in CTDB

[Aurélien Mino]

2011/5/20 Lukáš Lalinský <lalinsky at gmail.com>

>
> > I have several questions.
> > First thing that i noticed after setting up a database is that release
> > lookup by cdtoc was slow.
> > Using 'EXPLAIN ANALYZE' command i found out that it was because one of
> the
> > indexes was missing on medium_cdtoc table.
> > I fixed it with the following: 'CREATE INDEX medium_cdtoc_idx_cdtoc ON
> > medium_cdtoc (cdtoc)'
> > Is this intentional or was this done manually on the main server and
> > forgotten in admin/sql/CreateIndexes.sql?
> > Isn't the main musicbrainz server slowed down by this?
>
> MusicBrainz never uses the CD TOC directly for searching. It either
> uses the DiscID for exact matches (which is really just a SHA-1 hash
> of the CD TOC)
>

This is partially true.
MusicBrainz indeed doesn't use the CD TOC itself, but technically each time
you do a CD lookup,
the table medium_cdtoc will be queried with a filter on the 'cdtoc' field.

https://github.com/metabrainz/musicbrainz-server/blob/master/lib/MusicBrainz/Server/Data/MediumCDTOC.pm#L64

And thus this index is indeed missing.
Thanks for reporting it, Gregory, I've created a ticket in our tracker for
it:

http://tickets.musicbrainz.org/browse/MBS-2157

- Aurélien
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