Initially, idea was to ensure that when we come and check data
availability, special service table already contains one row. So if we
loose it for some reason, we will error out.
Yet, to do availability check we anyway start compute first! So it
doesn't really add some value, but we affect each compute start as we
update at least one row in the database. Also this writes some WAL, so
if timeline is close to `neon.max_cluster_size` it could prevent compute
from starting up.
That said, do CREATE TABLE IF NOT EXISTS + UPSERT right in the
`/check_writability` handler.
With this commit one can request compute reconfiguration
from the running `compute_ctl` with compute in `Running` state
by sending a new spec:
```shell
curl -d "{\"spec\": $(cat ./compute-spec-new.json)}" http://localhost:3080/configure
```
Internally, we start a separate configurator thread that is waiting on
`Condvar` for `ConfigurationPending` compute state in a loop. Then it does
reconfiguration, sets compute back to `Running` state and notifies other
waiters.
It will need some follow-ups, e.g. for retry logic for control-plane
requests, but should be useful for testing in the current state. This
shouldn't affect any existing environment, since computes are configured
in a different way there.
Resolvesneondatabase/cloud#4433
Sometimes, it contained real values, sometimes just defaults if the
spec was not received yet. Make the state more clear by making it an
Option instead.
One consequence is that if some of the required settings like
neon.tenant_id are missing from the spec file sent to the /configure
endpoint, it is spotted earlier and you get an immediate HTTP error
response. Not that it matters very much, but it's nicer nevertheless.
This is in preparation of using compute_ctl to launch postgres nodes
in the neon_local control plane. And seems like a good idea to
separate the public interfaces anyway.
One non-mechanical change here is that the 'metrics' field is moved
under the Mutex, instead of using atomics. We were not using atomics
for performance but for convenience here, and it seems more clear to
not use atomics in the model for the HTTP response type.
This commit adds an option to start compute without spec and then pass
it a valid spec via `POST /configure` API endpoint. This is a main
prerequisite for maintaining the pool of compute nodes in the
control-plane.
For example:
1. Start compute with
```shell
cargo run --bin compute_ctl -- -i no-compute \
-p http://localhost:9095 \
-D compute_pgdata \
-C "postgresql://cloud_admin@127.0.0.1:5434/postgres" \
-b ./pg_install/v15/bin/postgres
```
2. Configure it with
```shell
curl -d "{\"spec\": $(cat ./compute-spec.json)}" http://localhost:3080/configure
```
Internally, it's implemented using a `Condvar` + `Mutex`. Compute spec
is moved under Mutex, as it's now could be updated in the http handler.
Also `RwLock` was replaced with `Mutex` because the latter works well
with `Condvar`.
First part of the neondatabase/cloud#4433
Currently we don't see from the logs, if shutting down tracing takes
long time or not. We do see that shutting down computes gets delayed for
some reason and hits thhe grace period limit. Moving the shutdown
message to slightly later, when we don't have anything else than just
exit left.
## Issue ticket number and link
## Checklist before requesting a review
- [x] I have performed a self-review of my code.
- [ ] If it is a core feature, I have added thorough tests.
- [ ] Do we need to implement analytics? if so did you add the relevant
metrics to the dashboard?
- [ ] If this PR requires public announcement, mark it with
/release-notes label and add several sentences in this section.
We read the pageserver connection string from the spec file, so let's
read the auth token from the same place.
We've been talking about pre-launching compute nodes that are not
associated with any particular tenant at startup, so that the spec
file is delivered to the compute node later. We cannot change the env
variables after the process has been launched.
We still pass the token to 'postgres' binary in the NEON_AUTH_TOKEN
env variable, but compute_ctl is now responsible for setting it.
- Remove the neon.safekeeper_token_env GUC. It was used to set the
name of an environment variable, which was then used in pageserver
and safekeeper connection strings to in place of the
password. Instead, always look up the environment variable called
NEON_AUTH_TOKEN. That's what neon.safekeeper_token_env was always
set to in practice, and I don't see the need for the extra level of
indirection or configurability.
- Instead of substituting $NEON_AUTH_TOKEN in the connection strings,
pass $NEON_AUTH_TOKEN "out-of-band" as the password, when we connect
to the pageserver or safekeepers. That's simpler.
- Also use the password from $NEON_AUTH_TOKEN in compute_ctl, when it
connects to the pageserver to get the "base backup".
After enabling autoscaling, we faced the issue that customers are not
able to get the number of CPUs they use at this moment. Therefore I've
added these two options:
1. Postgresql function to allow customers to call it whenever they want
2. `compute_ctl` endpoint to show these number in console
This commit adds a basic HTTP API endpoint that allows scraping the
`pg_stat_statements` data and getting a list of slow queries. New
insights like cache hit rate and so on could be added later.
Extension `pg_stat_statements` is checked / created only if compute
tries to load the corresponding shared library. The latter is configured
by control-plane and currently covered with feature flag.
Co-authored by Eduard Dyckman (bird.duskpoet@gmail.com)
I added these spans to trace how long the queries take, but I didn't realize
that there's a difference between:
let _ = span.entered();
and
let _guard = span.entered();
The former drops the guard immediately, while the latter holds it
until the end of the scope. As a result, the span was ended
immediately, and the query was executed outside the span.
This allows fine-grained distributed tracing of the 'start_compute'
operation from the cloud console. The startup actions performed by
'compute_ctl' are now performed in a child of the 'start_compute'
context, so you can trace through the whole compute start operation.
This needs a corresponding change in the cloud console to fill in the
'startup_tracing_context' field in the json spec. If it's missing, the
startup operations are simply traced as a separate trace, without
a parent.
This allows tracing the startup actions e.g. with Jaeger
(https://www.jaegertracing.io/). We use the "tracing-opentelemetry"
crate, which turns tracing spans into OpenTelemetry spans, so you can
use the usual "#[instrument]" directives to add tracing.
I put the tracing initialization code to a separate crate,
`tracing-utils`, so that we can reuse it in other programs. We
probably want to set up tracing in the same way in all our programs.
Co-authored-by: Joonas Koivunen <joonas@neon.tech>
I noticed that `compute_ctl` updates all roles on each start, search for
rows like
> - web_access:[FILTERED] -> update
in the compute startup log.
It happens since we had an adhoc hack for md5 hashes comparison, which
doesn't work with scram hashes stored in the `pg_authid`. It doesn't
really hurt, as nothing changes, but we just run >= 2 extra queries on
each start, so fix it.
Previously, we were trying to re-assign owned objects of the already
deleted role. This were causing a crash loop in the case when compute
was restarted with a spec that includes delta operation for role
deletion. To avoid such cases, check that role is still present before
calling `reassign_owned_objects`.
Resolvesneondatabase/cloud#3553
Refactors Compute::prepare_and_run. It's split into subroutines
differently, to make it easier to attach tracing spans to the
different stages. The high-level logic for waiting for Postgres to
exit is moved to the caller.
Replace 'env_logger' with 'tracing', and add `#instrument` directives
to different stages fo the startup process. This is a fairly
mechanical change, except for the changes in 'spec.rs'. 'spec.rs'
contained some complicated formatting, where parts of log messages
were printed directly to stdout with `print`s. That was a bit messed
up because the log normally goes to stderr, but those lines were
printed to stdout. In our docker images, stderr and stdout both go to
the same place so you wouldn't notice, but I don't think it was
intentional.
This changes the log format to the default
'tracing_subscriber::format' format. It's different from the Postgres
log format, however, and because both compute_tools and Postgres print
to the same log, it's now a mix of two different formats. I'm not
sure how the Grafana log parsing pipeline can handle that. If it's a
problem, we can build custom formatter to change the compute_tools log
format to be the same as Postgres's, like it was before this commit,
or we can change the Postgres log format to match tracing_formatter's,
or we can start printing compute_tool's log output to a different
destination than Postgres
The general idea is that the VM informant binary is added to the
vm-compute-node images only. `compute_tools` then will run whatever's at
`/bin/vm-informant`, if the path exists.
Scan core dumps directory on exit. In case of existing core dumps
call gdb/lldb to get a backtrace and log it. By default look for
core dumps in postgres data directory as core.<pid>. That is how
core collection is configured in our k8s nodes (and a reasonable
convention in general).
1.66 release speeds up compile times for over 10% according to tests.
Also its Clippy finds plenty of old nits in our code:
* useless conversion, `foo as u8` where `foo: u8` and similar, removed
`as u8` and similar
* useless references and dereferenced (that were automatically adjusted
by the compiler), removed various `&` and `*`
* bool -> u8 conversion via `if/else`, changed to `u8::from`
* Map `.iter()` calls where only values were used, changed to
`.values()` instead
Standing out lints:
* `Eq` is missing in our protoc generated structs. Silenced, does not
seem crucial for us.
* `fn default` looks like the one from `Default` trait, so I've
implemented that instead and replaced the `dummy_*` method in tests with
`::default()` invocation
* Clippy detected that
```
if retry_attempt < u32::MAX {
retry_attempt += 1;
}
```
is a saturating add and proposed to replace it.
This fixes all kinds of problems related to missing params,
like broken timestamps (due to `integer_datetimes`).
This solution is not ideal, but it will help. Meanwhile,
I'm going to dedicate some time to improving connection machinery.
Note that this **does not** fix problems with passing certain parameters
in a reverse direction, i.e. **from client to compute**. This is a
separate matter and will be dealt with in an upcoming PR.
`GRANT CREATE ON SCHEMA public` fails if there is no schema `public`.
Disable it in release for now and make a better fix later (it is
needed for v15 support).
We've got at least one user in production that cannot create a
database with a trailing space in the name.
This happens because we use `url` crate for manipulating the
DATABASE_URL, but it follows a standard that doesn't fit really
well with Postgres. For example, it trims all trailing spaces
from the path:
> Remove any leading and trailing C0 control or space from input.
> See: https://url.spec.whatwg.org/#url-parsing
But we used `set_path()` to set database name and it's totally valid
to have trailing spaces in the database name in Postgres.
Thus, use `postgres::config::Config` to modify database name in the
connection details.
