Subject: [bug#32879] [PATCH] database: Add builds only if one of their outputs is new.

From: [email-masked] (Ludovic Courtès)
Date: Sun, 30 Sep 2018 21:34:12 +0200

Hello Clément,

Clément Lassieur <[email-masked]> skribis:

> * Makefile.am (dist_sql_DATA): Add 'src/sql/upgrade-4.sql'.
> * src/cuirass/database.scm (db-add-output): New procedure.
> (db-add-build): Call DB-ADD-OUTPUT, rollback the transaction and return #f if
> DB-ADD-OUTPUT returned an empty list.
> * src/schema.sql (Outputs): Set 'path' as primary key, instead of 'derivation,
> name'.
> * src/sql/upgrade-4.sql: New file with SQL queries to upgrade the database.
> * tests/database.scm (make-dummy-build): Use the #:OUTPUTS key.  Get default
> OUTPUTS to depend on DRV.
> ("db-add-build-with-fixed-output"): New test.

What’s the rationale?  I suppose having a simpler primary key for
‘Outputs’ might help performance?

Thank you,
Ludo’.