Remove internal schema cache load and relationship load sleep settings plus
the delay wrappers they enabled. Drop IO tests that depended on the removed
settings.
Right now metrics observation handler does not track database connections but updates a single Gauge based on HasqlPoolObs events. This is problematic because Hasql pool reports various connection events in multiple phases. The connection state machine is not simple and to precisely report the number of connections in various states, it is necessary to track their lifecycles.
This change adds a ConnTrack data structure and logic to track database connections lifecycles. At the moment it supports "connected" and "inUse" connection counts precisely. The "pgrst_db_pool_available" metric is implemented on top of ConnTrack instead of a simple Gauge.
PostgREST failed when querying role settings where current
role name contained uppercase letters. This commit resolves
it by quoting the CURRENT_USER.
Signed-off-by: Taimoor Zaeem <taimoorzaeem@gmail.com>
retryingSchemaCacheLoad flushes the pool upon every retry before it starts reloading the schema. This is too early as schema reloading might take some time during which new connections might be acquired. The consequence is that:
* upon successful schema cache reload we might have some connections created with the old schema cache
* we close connections upon each retry and under load we will keep closing and re-opening connections until schema cache load succeeds
This change is to make sure we flush the pool only after successful schema cache querying but before loading (so that connections acquired during loading wait for it and do not interfere with timing the loading process).
Diagnosing problems with listener channel notifications not being handled properly by PostgREST connected to read replicas is difficult. Issues might be related to lost connections and listener not being connected to the right host after failover or database server restarts.
This patch adds logging of actual host:port used by libpq connection opened by the listener. It should make it easier to find out if PostgREST is connected to the right host.
Some helpers are provided for introspecting metrics already (used in JWT cache tests). This change provides facilities to additionally validate emited Observation events.
A new Spec module is also implemented, adding basic tests of schema cache reloading - their main goal is to excercise the new infrastructure.
Right now listening sockets initialization, management and usage is split between App, AppState and Admin modules: they are created in AppState.init and remembered in AppState but used only in App and Admin.
It has several negative consequences:
- sockets are initialized even if not needed (eg. command line invocations like dump-config or dump-schema)
- it is impossible to start listening on a socket after initial schema cache load because it requires AppState
This change decouples listen socket management from AppState. Sockets are created only when needed (ie. not in command line tools invocation) and passed to admin application and to Warp by the App module.
- Create separate test suite for observability tests
- Create wrapper script `postgrest-test-observability`
- Add to CI and `postgrest-check`
- Move JWT cache tests under observability tests
Signed-off-by: Taimoor Zaeem <taimoorzaeem@gmail.com>
