We don't rely on sequential / monotonic build IDs processing anymore, so
randomizing actually has the advantage of mixing builds for different
systems together, to avoid only one chunk of builds for a single system
getting processed while builders for other systems are starved.
Each output for a given step being ingested is looked up in parallel,
which should basically multiply the speed of builds ingestion by the
average number of outputs per derivation.
Running the query with/without it shows that it makes no difference to
postgres, since there's an index on finished=0 already. This allows a
few simplifications, but also paves the way towards running multiple
parallel monitor threads in the future.
By looking at the ratio of running vs. waiting for the dispatcher and
the queue monitor, we should get better visibility into what hydra is
currently bottlenecked on.
There are other side effects we can try to measure to get to the same
result, but having a simple way doesn't cost us much.
This is implement in an extremely hacky way due to poor DBIx feature
support. Ideally, what we'd need is a way to tell DBIx to ignore the
errormsg column unless explicitly requested, and to automatically add a
computed 'errormsg IS NULL' column in others. Since it does not support
that, this commit instead hacks some support via method overrides while
taking care to not break anything obvious.
My current theory is that running more parallel xz than available CPU
cores is reducing our overall throughput by requiring more scheduling
overhead and more cache thrashing.
When building e.g. nixpkgs, the "Running builds" view will mostly look
like this
hello.x86_64-linux (Build of hello-X.Y)
exa.x86_64-linux (Build of exa-X.Y)
...
This doesn't provide any useful information. Showing the step name only
makes sense if it's not a child of the job's derivation. With this
patch, that information will only be shown if the drv name (i.e. w/o
`/nix/store/` prefix, .drv ext & hash) is not equal to the drv name of
the job itself (build.nixname).
When using Hydra to build machine configurations, you'll often see
"nixosConfigurations.foo" five times, i.e. for each build step being
run. This isn't very helpful I think because in such a case, a single
build step can also be compiling the Linux kernel.
This change also fetches the `drvpath` and `type` from the `buildsteps`
relation. We're already joining it, so this doesn't make much difference
(confirmed via query logging that this doesn't cause extra SQL queries).
Unfortunately build steps don't have a human readable name, so I'm
deriving it from the drvpath by stripping away the hash (assuming that
it'll never contain a `-` and that `/nix/store/` is used as prefix). I
decided against using the Nix bindings for that to avoid too much
overhead due to store operations for each build step.
In 73694087a0 I gave builds that failed
because of a timeout or exceeded log limit a stop sign and I stand by
that reasoning: with that it's possible to distinguish between actual
build failures and rather transient things such as timeouts.
Back then I considered it a feature that these are shown in a different
tab, but I don't think that's a good idea anymore. When using a jobset to
e.g. track the regressions from a mass rebuild (like a compiler or gcc
update), "Newly failed builds" should exclusively display regressions (and
flaky builds of course, not much I can do about that).
Also, when a bunch of builds fail in such a jobset because of e.g. a
broken connection to a builder that results in a timeout, I want to be
able to restart them all w/o rebuilding actual regressions.
To make it clear that we not only have "Aborted" builds in the tab, I
renamed the label to "Aborted / Timed out".
Closes#1336
When restarting postgresql, the connections are still reused in
`hydra-queue-runner` causing errors like this
main thread: Lost connection to the database server.
queue monitor: Lost connection to the database server.
and no more builds being processed.
`hydra-evaluator` doesn't have that issue since it crashes right away.
We could let it retry indefinitely as well (see below), but I don't
want to change too much.
If the DB is still unreachable 10s later, the process will stop with a
non-zero exit code because of a missing DB connection. This however
isn't such a big deal because it will be immediately restarted
afterwards. With the current configuration, Hydra will never give up,
but restart (and retry) infinitely. To me that seems reasonable, i.e. to
retry DB connections on a long-running process. If this doesn't work
out, the monitoring should fire anyways because the queue fills up, but
I'm open to discuss that.
Please note that this isn't reproducible with the DB and the queue
runner on the same machine when using `services.hydra-dev`, because of
the `Requires=` dependency `hydra-queue-runner.service` ->
`hydra-init.service` -> `postgresql.service` that causes the queue
runner to be restarted on `systemctl restart postgresql`.
Internally, Hydra uses Nix's pool data structure: it basically has N
slots (here DB connections) and whenever a new one is requested, an idle
slot is provided or a new one is created (when N slots are active, it'll
be waited until one slot is free). The issue in the code here is however
that whenever an error is encountered, the slot is released, however the
same broken connection will be reused the next time. By using
`Pool::Handle::markBad`, Nix will drop a broken slot. This is now being
done when `pqxx::broken_connection` was caught.
It's a pet peeve from me when logging into my personal Hydra that I
always have to press the button rather than hitting Return after entering
my password.
Reason for that is that the form doesn't have a "submit" button, so far
it was always listened to the "click" event. Submit does that and you
can hit Return alternatively.
This verison has a worse UI, but also chnages the schema less: One
non-null constraint is removed, but no new columns are added.
Co-Authored-By: Andrea Ciceri <andrea.ciceri@autistici.org>
Co-Authored-By: regnat <rg@regnat.ovh>
We have to oddly make a `StoreConfig` subclass to get it, but
https://github.com/NixOS/nix/pull/9848 will fix that.
The purpose of this is to ensure that, absent an explicit config,
`localhost` includes `ca-derivations` and `recursive-nix` if those
experimental features are enabled.
Very much the complement of #1342, the previous PR.
A slight dedup, and also ensures that floating CA derivations require a
`ca-derivations` experimental feature. This fixes the scheduling issue
that @SuperSandro2000 found.
This is *just* using the fields from that type, and only where the types
coincide. (There are two fields with different types, `speedFactor` most
interestingly.) No code is reused, so we can be sure that no behavior is
changed.
Once the types are reconciled on the Nix side, then we can start
carefully actually reusing code.
Progress on #1164
Instead of doing this partial operation a number of times, assert (with
a comment, get a reference to the thing inside, and use that just once.
(This refactor was done twice, "just once" for each time.)
It has a performance cost, and as the comment says we should be doing
the better solution. We want to land this preparatory change on prod
while the rest is still on staging, so we should just skip it for now.
Skipping it will not affect regular fixed-output and input-addressed
derivations, which are the only ones prod would deal with upon getting
this code.
The main CA derivations support branch will revert this commit so it
still works.
For the record, here is the Nix 2.19 version:
https://github.com/NixOS/nix/blob/2.19-maintenance/src/libstore/serve-protocol.cc,
which is what we would initially use.
It is a more complete version of what Hydra has today except for one
thing: it always unconditionally sets the start/stop times.
I think that is correct at the other end seems to unconditionally
measure them, but just to be extra careful, I reproduced the old
behavior of falling back on Hydra's own measurements if `startTime` is
0.
The only difference is that the fallback `stopTime` is now measured from
after the entire `BuildResult` is transferred over the wire, but I think
that should be negligible if it is measurable at all. (And remember,
this is fallback case I already suspect is dead code.)
An empty string is a sneaky way to avoid hard failures --- things that
expect strings still get strings, but it does conversely open the door
up to soft failures (spooky-action-at-a-distance ones because the string
did not have the expected invariants).
"Fail fast" with null will ultimately make the system more robust, but
force us to fix more things up front, and I don't want to change this
without also fixing those things up front, especially as this commit is
for now just part of the the preparatory PR for which this is dead code.
Brought up by @thufschmitt in
https://github.com/NixOS/hydra/pull/1316#discussion_r1415111329 . This
makes this closer to what was originally there --- which just dispatched
off the experimental feature rather than the presence/absense of the
output, too.
This is just C++ changes without any Perl / Frontend / SQL Schema
changes.
The idea is that it should be possible to redeploy Hydra with these
chnages with (a) no schema migration and also (b) no regressions. We
should be able to much more safely deploy these to a staging server and
then production `hydra.nixos.org`.
Extracted from #875
Co-Authored-By: Théophane Hufschmitt <theophane.hufschmitt@tweag.io>
Co-Authored-By: Alexander Sosedkin <monk@unboiled.info>
Co-Authored-By: Andrea Ciceri <andrea.ciceri@autistici.org>
Co-Authored-By: Charlotte 🦝 Delenk Mlotte@chir.rs>
Co-Authored-By: Sandro Jäckel <sandro.jaeckel@gmail.com>
Pierre Bourdon
Maximilian Bosch
Ilya K
