* Don't use isCurrent anymore; instead look up builds in the previous
jobset evaluation. (The isCurrent field is still maintained because
it's still used in some other places.)
* To determine whether to perform an evaluation, compare the hash of
the current inputs with the inputs of the previous jobset
evaluation, rather than checking if there was ever an evaluation
with those inputs. This way, if the inputs of an evaluation change
back to a previous state, we get a new jobset evaluation in the
database (and thus the latest jobset evaluation correctly represents
the latest state of the jobset).
* Improve performance by removing some unnecessary operations and
adding an index.
Prepared statements are sometimes much slower than unprepared
statements, because the planner doesn't have access to the query
parameters. This is the case for the active build steps query (in
/status), where a prepared statement is three orders of magnitude
slower. So disable the use of prepared statements in this case.
(Since the query parameters are constant here, it would be nicer if we
could tell DBIx::Class to prepare a statement with those parameters
fixed. But I don't know an easy way to do so.)
For schema upgrades, hydra-init executes the files
src/sql/upgrade-<N>.sql, each of which upgrades the schema from
version N-1 to N. The upgrades are wrapped in a transaction.
Since a build may be a member of multiple jobset evaluations, we need
to do a "select distinct" here. But maybe we should only show builds
from a single evaluation (e.g. the most recent), since showing builds
from several may be confusing.
The abbreviated Git revision hash (e.g. "267480b") is typically
contained in ‘gitTag’ as well, but the latter can contain other
elements as well, e.g., the delta to the closest tag. That may
be undesirable in version strings, so this is an alternative.
The ‘revCount’ attribute is the number of commits in the history
of the revision. This is useful if you need a monotonically
increasing version number.
The ‘gitTag’ attribute is the output of ‘git describe’, e.g.
‘v1.0.4-14-g2414721’ to indicate that the current revision is 14
commits after the tag ‘v1.0.4’.
The singleton table SchemaVersion contains the current version
of the Hydra database schema. This can be used to upgrade the
schema on the fly.
Also reran the DBIx::Class schema loader.
In hydra-evaluator, reuse an SVN working copy between runs (similar to
what we do with Git and other input types). This reduces network
traffic in the common case.
Also, don't use nix-prefetch-svn. It doesn't do anything useful.
The "all" channel fundamentally doesn't scale, because it needs
to fetch N builds from the database (where N is potentially a very
large number), then check whether they are still valid. And it's
not very useful anyway.
