These changes were motivated by switching to a mechanism of loading data that
isn't dependent on the big advisory lock that prevents more than one revision
from being processed at a time.
Since INSERT ... RETURNING id; is used, this can block if another transaction
inserts the same data, and then cause an error when that transaction
commits. The solution is to use ON CONFLICT DO NOTHING, but you have to handle
the case when the INSERT doesn't return an id since the other transaction has
inserted it.
This commit rewrites insert-missing-data-and-return-all-ids to do as described
above, as well as being more efficient in how existing data is detected and to
use more vectors. Other utilities for inserting data are added as well.
And create a proper git_branches table in the process.
I'm hoping this will help with slow deletions from the
package_derivations_by_guix_revision_range table in the case where there are
lots of branches, since it'll separate the data for one branch from another.
These migrations will remove the existing data, so
rebuild-package-derivations-table will currently need manually running to
regenerate it.
squee, returns all data as strings, and expects strings as inputs to
queries. So, keeping the ids as strings was easy initially, but it means that
you can't tell from the type whether it should be quoted, or not...
Therefore, handle ids as strings, converting them to numbers when they're
fetched from the database, and back to strings as part of the queries.
This makes is easier to get the latest data for a branch in a single request,
rather than making one request to find the latest revision, then another to
get the data.
Add some new pages /branches and /branch/... as well as a new git_branches
table. Also extend the email processing to enter the branch information in to
the database.
