bump version to 14.10

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).

.github/actions/artifact-from-cirrus/action.yaml

@@ -112,7 +112,7 @@ runs:
         echo "artifacts=${artifacts}" >> "$GITHUB_OUTPUT"
     - name: Save artifact to GitHub Actions
       if: steps.find-task.outputs.task_found
-      uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f # v7.0.0
+      uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
       with:
         name: ${{ inputs.upload }}
         path: ${{ steps.download.outputs.artifacts }}

.github/actions/cache-on-main/action.yaml

@@ -19,14 +19,14 @@ inputs:
 runs:
   using: composite
   steps:
-    - uses: actions/cache@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
+    - uses: actions/cache@27d5ce7f107fe9357f9df03efb73ab90386fccae # v5.0.5
       if: ${{ startsWith(github.ref, 'refs/heads/') || (inputs.save-prs && startsWith(github.ref, 'refs/pull/')) }}
       with:
         path: ${{ inputs.path }}
         key: ${{ runner.os }}-${{ inputs.prefix }}-${{ inputs.suffix }}
         restore-keys: |
           ${{ runner.os }}-${{ inputs.prefix }}-
-    - uses: actions/cache/restore@668228422ae6a00e4ad889ee87cd7109ec5666a7 # v5.0.4
+    - uses: actions/cache/restore@27d5ce7f107fe9357f9df03efb73ab90386fccae # v5.0.5
       if: ${{ !startsWith(github.ref, 'refs/heads/') && !(inputs.save-prs && startsWith(github.ref, 'refs/pull/'))  }}
       with:
         path: ${{ inputs.path }}

.github/workflows/backport.yaml

@@ -28,7 +28,7 @@ jobs:
       # This actions creates the github token using the postgrest app secrets
       - name: Create Github App Token
         id: app-token
-        uses: actions/create-github-app-token@f8d387b68d61c58ab83c6c016672934102569859 # v3.0.0
+        uses: actions/create-github-app-token@1b10c78c7865c340bc4f6099eb2f838309f1e8c3 # v3.1.1
         with:
           app-id: ${{ vars.POSTGREST_CI_APP_ID }}
           private-key: ${{ secrets.POSTGREST_CI_PRIVATE_KEY }}

.github/workflows/build.yaml

@@ -42,7 +42,7 @@ jobs:
       - name: Build static executable
         run: nix-build -A postgrestStatic -A postgrestStatic.tests
       - name: Save built executable as artifact
-        uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f # v7.0.0
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
         with:
           name: postgrest-linux-static-x86-64
           path: result/bin/postgrest
@@ -51,7 +51,7 @@ jobs:
       - name: Build Docker image
         run: nix-build -A docker.image --out-link postgrest-docker.tar.gz
       - name: Save built Docker image as artifact
-        uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f # v7.0.0
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
         with:
           name: postgrest-docker-x86-64
           path: postgrest-docker.tar.gz
@@ -118,7 +118,7 @@ jobs:
     runs-on: ${{ matrix.runs-on }}
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
-      - uses: haskell-actions/setup@f9150cb1d140e9a9271700670baa38991e6fa25c # v2.10.3
+      - uses: haskell-actions/setup@cd0d9bdd65b20557f41bea4dbe43d0b5fbbfe553 # v2.11.0
         with:
           # This must match the version in stack.yaml's resolver
           ghc-version: 9.6.7
@@ -146,7 +146,7 @@ jobs:
       - name: Strip Executable
         run: strip result/postgrest*
       - name: Save built executable as artifact
-        uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f # v7.0.0
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
         with:
           name: ${{ matrix.artifact }}
           path: |
@@ -177,7 +177,7 @@ jobs:
     runs-on: ubuntu-24.04
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
-      - uses: haskell-actions/setup@f9150cb1d140e9a9271700670baa38991e6fa25c # v2.10.3
+      - uses: haskell-actions/setup@cd0d9bdd65b20557f41bea4dbe43d0b5fbbfe553 # v2.11.0
         with:
           ghc-version: ${{ matrix.ghc }}
       - name: Cache .cabal

.github/workflows/release.yaml

@@ -49,7 +49,7 @@ jobs:
           echo "Relevant extract from CHANGELOG.md:"
           cat CHANGES.md
       - name: Save CHANGES.md as artifact
-        uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f # v7.0.0
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
         with:
           name: release-changes
           path: CHANGES.md
@@ -91,7 +91,7 @@ jobs:
             artifacts/postgrest-windows-x86-64/postgrest.exe
 
       - name: Save release bundle
-        uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f # v7.0.0
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
         with:
           name: release-bundle
           path: release-bundle

CHANGELOG.md

@@ -4,6 +4,26 @@ All notable changes to this project will be documented in this file. From versio
 
 ## Unreleased
 
+## [14.10] - 2026-04-16
+
+### Added
+
+- Log when the pool is released during schema cache reload on `log-level=debug` by @mkleczek in #4668
+
+### Fixed
+
+- Fix unnecessary connection pool flushes during schema cache reloading by @mkleczek in #4645
+
+## [14.9] - 2026-04-10
+
+### Added
+
+- Log host, port and pg version of listener database connection by @mkleczek in #4617 #4618
+
+### Fixed
+
+- Remove red herring warp logs on default log-level, only emit them on `log-level=debug` by @steve-chavez in #4799
+
 ## [14.8] - 2026-04-03
 
 ### Added

Dockerfile

@@ -2,7 +2,7 @@
 # The x86-64 is a single-static-binary image built via Nix, see:
 # nix/tools/docker/README.md
 
-FROM ubuntu:noble@sha256:186072bba1b2f436cbb91ef2567abca677337cfc786c86e107d25b7072feef0c AS postgrest
+FROM ubuntu:noble@sha256:c4a8d5503dfb2a3eb8ab5f807da5bc69a85730fb49b5cfca2330194ebcc41c7b AS postgrest
 
 RUN apt-get update -y \
     && apt install -y --no-install-recommends libpq-dev zlib1g-dev jq gcc libnuma-dev \

docs/ecosystem.rst

@@ -6,7 +6,7 @@ Community Tutorials
 * `Building a Contacts List with PostgREST and Vue.js <https://www.youtube.com/watch?v=iHtsALtD5-U>`_ -
   In this video series, DigitalOcean shows how to build and deploy an Nginx + PostgREST(using a managed PostgreSQL database) + Vue.js webapp in an Ubuntu server droplet.
 
-* `PostgREST + Auth0: Create REST API in mintutes, and add social login using Auth0 <https://samkhawase.com/blog/postgrest/>`_ - A step-by-step tutorial to show how to dockerize and integrate Auth0 to PostgREST service.
+* `PostgREST + Auth0: Create REST API in minutes, and add social login using Auth0 <https://samkhawase.com/blog/postgrest-1-introduction/>`_ - A step-by-step tutorial to show how to dockerize and integrate Auth0 to PostgREST service.
 
 * `"CodeLess" backend using postgres, postgrest and oauth2 authentication with keycloak <https://www.mathieupassenaud.fr/codeless_backend/>`_ -
   A step-by-step tutorial for using PostgREST with KeyCloak(hosted on a managed service).

docs/references/api/url_grammar.rst

@@ -14,7 +14,7 @@ Custom Queries
 
 The PostgREST URL grammar limits the kinds of queries clients can perform. It prevents arbitrary, potentially poorly constructed and slow client queries. It's good for quality of service, but means database administrators must create custom views and functions to provide richer endpoints. The most common causes for custom endpoints are
 
-* Table unions
+* SET operators like `UNION, INTERSECT and EXCEPT <https://www.postgresql.org/docs/current/queries-union.html>`_.
 * More complicated joins than those provided by :ref:`resource_embedding`.
 * Geo-spatial queries that require an argument, like "points near (lat,lon)"
 

docs/references/listener.rst

@@ -46,7 +46,9 @@ This will cause the :ref:`connection_pool` to connect to the read replica host a
 
 .. note::
 
-  Under the hood, PostgREST forces `target_session_attrs=read-write <https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-CONNECT-TARGET-SESSION-ATTRS>`_ for the ``LISTEN`` session.
+  - Under the hood, PostgREST forces `target_session_attrs=read-write <https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-CONNECT-TARGET-SESSION-ATTRS>`_ for the ``LISTEN`` session.
+    So if you specify ``target_session_attrs=read-only`` as mentioned above, PostgREST will override it for the ``LISTEN``.
+  - ``read-only`` is only available on libpq >= 14, if you use a lower version you will get an error like ``invalid target_session_attrs value: \"read-only\"``.
 
 .. _listener_automatic_recovery:
 

postgrest.cabal

@@ -1,5 +1,5 @@
 name:               postgrest
-version:            14.8
+version:            14.10
 synopsis:           REST API for any Postgres database
 description:        Reads the schema of a PostgreSQL database and creates RESTful routes
                     for tables, views, and functions, supporting all HTTP methods that security
@@ -304,6 +304,7 @@ test-suite observability
   other-modules:      ObsHelper
                       Observation.JwtCache
                       Observation.MetricsSpec
+                      Observation.SchemaCacheSpec
   build-depends:      base              >= 4.9 && < 4.20
                     , base64-bytestring >= 1 && < 1.3
                     , bytestring        >= 0.10.8 && < 0.13

src/PostgREST/App.hs

@@ -98,7 +98,7 @@ run appState = do
     onWarpException :: Maybe Wai.Request -> SomeException -> IO ()
     onWarpException _ ex =
       when (shouldDisplayException ex) $
-        observer $ WarpErrorObs $ show ex
+        observer $ WarpServerObs $ show ex
 
     -- Similar to wai defaultShouldDisplayException in
     -- https://github.com/yesodweb/wai//blob/8c3882c60f6abe043889fc20c7efd3fa9747fa4a/warp/Network/Wai/Handler/Warp/Settings.hs#L251-L258

src/PostgREST/AppState.hs

@@ -219,10 +219,14 @@ usePool AppState{stateObserver=observer, stateMainThreadId=mainThreadId, ..} ses
 
 -- | Flush the connection pool so that any future use of the pool will
 -- use connections freshly established after this call.
+-- | Emits PoolFlushed observation
 flushPool :: AppState -> IO ()
-flushPool AppState{..} = SQL.release statePool
+flushPool AppState{..} = do
+  SQL.release statePool
+  stateObserver PoolFlushed
 
 -- | Destroy the pool on shutdown.
+-- | Differs from flushPool in not emiting PoolFlushed observation.
 destroyPool :: AppState -> IO ()
 destroyPool AppState{..} = SQL.release statePool
 
@@ -309,8 +313,6 @@ retryingSchemaCacheLoad appState@AppState{stateObserver=observer, stateMainThrea
       observer $ ConnectionRetryObs delay
       putNextListenerDelay appState delay
 
-    flushPool appState
-
     (,) <$> qPgVersion <*> (qInDbConfig *> qSchemaCache)
   )
   where
@@ -359,6 +361,10 @@ retryingSchemaCacheLoad appState@AppState{stateObserver=observer, stateMainThrea
           -- IORef on putSchemaCache. This is why SCacheStatus is put at SCPending here to signal the Admin server (using isPending) that we're on a recovery state.
           putSCacheStatus appState SCPending
           putSchemaCache appState $ Just sCache
+          -- Flush the pool after loading the schema cache to reset any stale session cache entries
+          -- We do it after successfully querying the schema cache (because this can fail and during retries we would flush the pool repeatedly unnecessarily)
+          -- and after marking sCacheStatus as pending,
+          flushPool appState
           observer $ SchemaCacheQueriedObs resultTime
           (t, _) <- timeItT $ observer $ SchemaCacheSummaryObs $ showSummary sCache
           observer $ SchemaCacheLoadedObs t

src/PostgREST/Listener.hs

@@ -17,8 +17,14 @@ import           PostgREST.Version     (prettyVersion)
 import qualified PostgREST.AppState as AppState
 import qualified PostgREST.Config   as Config
 
-import Data.Either.Combinators (whenRight)
-import Protolude
+import           Control.Arrow              ((&&&))
+import           Data.Bitraversable         (bisequence)
+import           Data.Either.Combinators    (whenRight)
+import qualified Database.PostgreSQL.LibPQ  as LibPQ
+import qualified Hasql.Session              as SQL
+import           PostgREST.Config.Database  (queryPgVersion)
+import           PostgREST.Config.PgVersion (pgvFullName)
+import           Protolude
 
 -- | Starts the Listener in a thread
 runListener :: AppState -> IO ()
@@ -63,6 +69,9 @@ retryingListen appState = do
       \case
         Right db -> do
           SQL.listen db $ SQL.toPgIdentifier dbChannel
+          (pqHost, pqPort) <- SQL.withLibPQConnection db $ bisequence . (LibPQ.host &&& LibPQ.port)
+          pgFullName <- SQL.run (queryPgVersion False) db >>= either throwIO (pure . pgvFullName)
+
           AppState.putIsListenerOn appState True
 
           delay <- AppState.getNextListenerDelay appState
@@ -72,7 +81,7 @@ retryingListen appState = do
             -- reset the delay
             AppState.putNextListenerDelay appState 1
 
-          observer $ DBListenStart dbChannel
+          observer $ DBListenStart pqHost pqPort pgFullName dbChannel
 
           -- wait for notifications
           -- this will never return, in case of an error it will throw and be caught by onError

src/PostgREST/Logger.hs

@@ -110,12 +110,18 @@ observationLogger loggerState logLevel obs = case obs of
   o@PoolRequestFullfilled ->
     when (logLevel >= LogDebug) $ do
       logWithZTime loggerState $ observationMessage o
+  o@PoolFlushed ->
+    when (logLevel >= LogDebug) $ do
+      logWithZTime loggerState $ observationMessage o
   o@JwtCacheEviction ->
     when (logLevel >= LogDebug) $ do
       logWithZTime loggerState $ observationMessage o
   o@(JwtCacheLookup _) ->
     when (logLevel >= LogDebug) $ do
       logWithZTime loggerState $ observationMessage o
+  o@(WarpServerObs _) ->
+    when (logLevel >= LogDebug) $ do
+      logWithZTime loggerState $ observationMessage o
   o ->
     logWithZTime loggerState $ observationMessage o
 

src/PostgREST/Observation.hs

@@ -45,7 +45,7 @@ data Observation
   | SchemaCacheSummaryObs Text
   | SchemaCacheLoadedObs Double
   | ConnectionRetryObs Int
-  | DBListenStart Text
+  | DBListenStart (Maybe ByteString) (Maybe ByteString) Text Text -- host, port, version string, channel
   | DBListenFail Text (Either SQL.ConnectionError SomeException)
   | DBListenRetry Int
   | DBListenBugHint -- https://github.com/PostgREST/postgrest/issues/3147
@@ -64,10 +64,11 @@ data Observation
   | HasqlPoolObs SQL.Observation
   | PoolRequest
   | PoolRequestFullfilled
+  | PoolFlushed
   | JwtCacheLookup Bool
   | JwtCacheEviction
   | TerminationUnixSignalObs Text
-  | WarpErrorObs Text
+  | WarpServerObs Text
   deriving (Generic)
 
 data ObsFatalError = ServerAuthError | ServerPgrstBug | ServerError42P05 | ServerError08P01
@@ -114,8 +115,8 @@ observationMessage = \case
     "Attempting to reconnect to the database in " <> (show delay::Text) <> " seconds..."
   QueryPgVersionError usageErr ->
     "Failed to query the PostgreSQL version. " <> jsonMessage usageErr
-  DBListenStart channel -> do
-    "Listening for database notifications on the " <> show channel <> " channel"
+  DBListenStart host port fullName channel -> do
+    "Listener connected to " <> fullName <> " on " <> show (fold $ host <> fmap (":" <>) port) <> " and listening for database notifications on the " <> show channel <> " channel"
   DBListenFail channel listenErr ->
     "Failed listening for database notifications on the " <> show channel <> " channel. " <>
       either showListenerConnError showListenerException listenErr
@@ -161,14 +162,16 @@ observationMessage = \case
     "Trying to borrow a connection from pool"
   PoolRequestFullfilled ->
     "Borrowed a connection from the pool"
+  PoolFlushed ->
+    "Database connection pool flushed"
   JwtCacheLookup _ ->
     "Looked up a JWT in JWT cache"
   JwtCacheEviction ->
     "Evicted entry from JWT cache"
   TerminationUnixSignalObs signal ->
     "Received termination unix signal " <> signal
-  WarpErrorObs txt ->
-    "Warp server error: " <> txt
+  WarpServerObs txt ->
+    "Warp server: " <> txt
   where
     showMillis :: Double -> Text
     showMillis x = toS $ showFFloat (Just 1) x ""

test/io/test_big_schema.py

@@ -55,13 +55,15 @@ def test_openapi_in_big_schema(defaultenv):
         assert response.status_code == 200
 
 
-def test_stackoverflow_is_logged(defaultenv):
-    "Stack overflow errors should be logged with the Warp error message"
+@pytest.mark.parametrize("level", ["crit", "error", "warn", "info", "debug"])
+def test_stackoverflow_is_logged(level, defaultenv):
+    "Stack overflow should be logged with the Warp message only on log-level=debug"
 
     env = {
         **defaultenv,
         "PGRST_DB_SCHEMAS": "apflora",
         "PGRST_DB_ANON_ROLE": "postgrest_test_anonymous",
+        "PGRST_LOG_LEVEL": level,
     }
 
     with run(env=env, wait_max_seconds=30, no_startup_stdout=False) as postgrest:
@@ -69,9 +71,15 @@ def test_stackoverflow_is_logged(defaultenv):
             postgrest.session.get("/")
 
         output = postgrest.read_stdout(nlines=10)
-        output.extend(postgrest.read_stdout(nlines=10))
+        for _ in range(3):
+            output.extend(postgrest.read_stdout(nlines=10))
 
-        assert any("Warp server error: stack overflow" in line for line in output)
+        found = any("Warp server: stack overflow" in line for line in output)
+
+        if level == "debug":
+            assert found
+        else:
+            assert not found
 
 
 # See: https://github.com/PostgREST/postgrest/issues/3329

test/io/test_io.py

@@ -21,6 +21,19 @@ from postgrest import (
 )
 
 
+def match_log(output, matchers):
+    ito = iter(output)
+    itm = iter(matchers)
+    nextMatcher = next(itm, None)
+    while nextMatcher is not None and (line := next(ito, None)) is not None:
+        if re.match(nextMatcher, line) is not None:
+            nextMatcher = next(itm, None)
+    if nextMatcher is not None:
+        raise AssertionError(
+            f"Expected log line matching {nextMatcher} not found in output"
+        )
+
+
 def test_connect_with_dburi(dburi, defaultenv):
     "Connecting with db-uri instead of LIPQ* environment variables should work."
     defaultenv_without_libpq = {
@@ -679,55 +692,45 @@ def test_log_level(level, defaultenv):
         response = postgrest.session.get("/")
         assert response.status_code == 200
 
-        output = sorted(postgrest.read_stdout(nlines=7))
+        output = postgrest.read_stdout(nlines=9)
 
         if level == "crit":
             assert len(output) == 0
         elif level == "error":
-            assert re.match(
-                r'- - - \[.+\] "GET / HTTP/1.1" 500 \d+ "" "python-requests/.+"',
-                output[0],
+            match_log(
+                output,
+                [r'- - - \[.+\] "GET / HTTP/1.1" 500 \d+ "" "python-requests/.+"'],
             )
             assert len(output) == 1
         elif level == "warn":
-            assert re.match(
-                r'- - - \[.+\] "GET / HTTP/1.1" 500 \d+ "" "python-requests/.+"',
-                output[0],
-            )
-            assert re.match(
-                r'- - postgrest_test_anonymous \[.+\] "GET /unknown HTTP/1.1" 404 \d+ "" "python-requests/.+"',
-                output[1],
+            match_log(
+                output,
+                [
+                    r'- - - \[.+\] "GET / HTTP/1.1" 500 \d+ "" "python-requests/.+"',
+                    r'- - postgrest_test_anonymous \[.+\] "GET /unknown HTTP/1.1" 404 \d+ "" "python-requests/.+"',
+                ],
             )
             assert len(output) == 2
         elif level == "info":
-            assert re.match(
-                r'- - - \[.+\] "GET / HTTP/1.1" 500 \d+ "" "python-requests/.+"',
-                output[0],
-            )
-            assert re.match(
-                r'- - postgrest_test_anonymous \[.+\] "GET / HTTP/1.1" 200 \d+ "" "python-requests/.+"',
-                output[1],
-            )
-            assert re.match(
-                r'- - postgrest_test_anonymous \[.+\] "GET /unknown HTTP/1.1" 404 \d+ "" "python-requests/.+"',
-                output[2],
+            match_log(
+                output,
+                [
+                    r'- - - \[.+\] "GET / HTTP/1.1" 500 \d+ "" "python-requests/.+"',
+                    r'- - postgrest_test_anonymous \[.+\] "GET /unknown HTTP/1.1" 404 \d+ "" "python-requests/.+"',
+                    r'- - postgrest_test_anonymous \[.+\] "GET / HTTP/1.1" 200 \d+ "" "python-requests/.+"',
+                ],
             )
             assert len(output) == 3
         elif level == "debug":
-            assert re.match(
-                r'- - - \[.+\] "GET / HTTP/1.1" 500 \d+ "" "python-requests/.+"',
-                output[0],
+            match_log(
+                output,
+                [
+                    r'- - - \[.+\] "GET / HTTP/1.1" 500 \d+ "" "python-requests/.+"',
+                    r'- - postgrest_test_anonymous \[.+\] "GET /unknown HTTP/1.1" 404 \d+ "" "python-requests/.+"',
+                    r'- - postgrest_test_anonymous \[.+\] "GET / HTTP/1.1" 200 \d+ "" "python-requests/.+"',
+                ],
             )
-            assert re.match(
-                r'- - postgrest_test_anonymous \[.+\] "GET / HTTP/1.1" 200 \d+ "" "python-requests/.+"',
-                output[1],
-            )
-            assert re.match(
-                r'- - postgrest_test_anonymous \[.+\] "GET /unknown HTTP/1.1" 404 \d+ "" "python-requests/.+"',
-                output[2],
-            )
-
-            assert len(output) == 7
+            assert len(output) == 9
             assert any("Connection" and "is available" in line for line in output)
             assert any("Connection" and "is used" in line for line in output)
 
@@ -1364,16 +1367,21 @@ def test_db_error_logging_to_stderr(level, defaultenv, metapostgrest):
         assert response.status_code == 500
 
         # ensure the message appears on the logs
-        output = sorted(postgrest.read_stdout(nlines=6))
+        output = postgrest.read_stdout(nlines=8)
 
         if level == "crit":
             assert len(output) == 0
         elif level == "debug":
-            assert " 500 " in output[0]
-            assert "canceling statement due to statement timeout" in output[5]
+            match_log(
+                output,
+                [
+                    r".*canceling statement due to statement timeout.*",
+                    r".*500.*",
+                ],
+            )
         else:
-            assert " 500 " in output[0]
-            assert "canceling statement due to statement timeout" in output[1]
+            assert " 500 " in output[1]
+            assert "canceling statement due to statement timeout" in output[0]
 
     reset_statement_timeout(metapostgrest, role)
 
@@ -1567,18 +1575,17 @@ def test_log_pool_req_observation(level, defaultenv):
 
     headers = jwtauthheader({"role": "postgrest_test_author"}, SECRET)
 
-    pool_req = "Trying to borrow a connection from pool"
-    pool_req_fullfill = "Borrowed a connection from the pool"
+    pool_req = r".*Trying to borrow a connection from pool.*"
+    pool_req_fullfill = r".*Borrowed a connection from the pool.*"
 
     with run(env=env) as postgrest:
 
         postgrest.session.get("/authors_only", headers=headers)
 
         if level == "debug":
-            output = postgrest.read_stdout(nlines=5)
-            assert pool_req in output[1]
-            assert pool_req_fullfill in output[4]
-            assert len(output) == 5
+            output = postgrest.read_stdout(nlines=7)
+            assert len(output) == 7
+            match_log(output, [pool_req, pool_req_fullfill])
         elif level == "info":
             output = postgrest.read_stdout(nlines=4)
             assert len(output) == 1
@@ -1658,6 +1665,25 @@ def test_log_listener_connection_errors(defaultenv):
         )
 
 
+def test_log_listener_connection_start(defaultenv):
+    "The logs should show the listener connection start message in a single line"
+
+    env = {
+        **defaultenv,
+        "PGRST_DB_CHANNEL_ENABLED": "true",
+    }
+
+    with run(env=env, no_startup_stdout=False, wait_for_readiness=True) as postgrest:
+        output = postgrest.read_stdout(nlines=10)
+        # Check for the listener start message containing host and port
+        # Do not check if pg version is displayed properly as it is tricky to test it
+        assert any(
+            f'"{defaultenv["PGHOST"]}:5432" and listening for database notifications on the "pgrst" channel'
+            in line
+            for line in output
+        )
+
+
 def test_db_pre_config_with_pg_reserved_words(defaultenv):
     "The db-pre-config should not fail unexpectedly when function name is a postgres reserved word"
 

test/observability/Main.hs

@@ -17,10 +17,11 @@ import           PostgREST.SchemaCache     (querySchemaCache)
 import qualified Observation.JwtCache
 import qualified Observation.MetricsSpec
 
-import ObsHelper
-import PostgREST.Observation (Observation (HasqlPoolObs))
-import Protolude             hiding (toList, toS)
-import Test.Hspec
+import qualified Observation.SchemaCacheSpec
+import           ObsHelper
+import           PostgREST.Observation       (Observation (HasqlPoolObs))
+import           Protolude                   hiding (toList, toS)
+import           Test.Hspec
 
 main :: IO ()
 main = do
@@ -64,6 +65,8 @@ main = do
       describe "Observation.JwtCacheObs" Observation.JwtCache.spec
     before (initApp baseSchemaCache testCfg) $
       describe "Feature.MetricsSpec" Observation.MetricsSpec.spec
+    before (initApp baseSchemaCache testCfg) $
+      describe "Feature.SchemaCacheSpec" Observation.SchemaCacheSpec.spec
 
   where
     loadSCache pool conf =

test/observability/ObsHelper.hs

@@ -206,5 +206,5 @@ waitForObs (ObsChan orig copy) t msg f =
 obsDiagMessage :: Observation -> Text
 obsDiagMessage = \case
   (HasqlPoolObs o) -> show o
-  o@(DBListenStart channel) -> constrName o <> show channel
+  o@(DBListenStart host port name channel) -> constrName o <> show (host, port, name, channel)
   o -> constrName o

test/observability/Observation/SchemaCacheSpec.hs

@@ -0,0 +1,49 @@
+{-# LANGUAGE DataKinds           #-}
+{-# LANGUAGE MonadComprehensions #-}
+{-# LANGUAGE NamedFieldPuns      #-}
+module Observation.SchemaCacheSpec where
+
+import           Network.Wai           (Application)
+import           ObsHelper
+import qualified PostgREST.AppState    as AppState
+import           PostgREST.Config      (configDbSchemas)
+import           PostgREST.Observation
+import           Protolude
+import           Test.Hspec            (SpecWith, describe, it)
+import           Test.Hspec.Wai        (getState)
+
+spec :: SpecWith (SpecState, Application)
+spec = describe "Server started with metrics enabled" $ do
+
+  it "Should emit PoolFlushed, SchemaCacheQueriedObs and SchemaCacheLoadedObs when schema cache is reloaded" $ do
+    SpecState{specAppState = appState, specObsChan} <- getState
+    let waitFor = waitForObs specObsChan
+
+    liftIO $ do
+      AppState.schemaCacheLoader appState
+
+      waitFor (1 * sec) "PoolFlushed" $ \x -> [ o | o@PoolFlushed <- pure x ]
+      waitFor (1 * sec) "SchemaCacheQueriedObs" $ \x -> [ o | o@SchemaCacheQueriedObs{} <- pure x ]
+      waitFor (1 * sec) "SchemaCacheLoadedObs" $ \x -> [ o | o@SchemaCacheLoadedObs{} <- pure x ]
+
+
+  it "Should flush pool once when schema reloading retries" $ do
+    SpecState{specAppState = appState, specObsChan} <- getState
+    let waitFor = waitForObs specObsChan
+
+    liftIO $ do
+        AppState.getConfig appState >>= \cfg -> do
+          AppState.putConfig appState $ cfg { configDbSchemas = pure "bad_schema" }
+          AppState.schemaCacheLoader appState
+
+          waitFor (1 * sec) "SchemaCacheErrorObs" $ \x -> [ o | o@SchemaCacheErrorObs{} <- pure x ]
+
+          -- Restore configuration
+          AppState.putConfig appState cfg
+
+        -- Wait for 2 seconds so that retry can happen
+        waitFor (2 * sec) "PoolFlushed" $ \x -> [ o | o@PoolFlushed <- pure x ]
+        waitFor (1 * sec) "SchemaCacheQueriedObs" $ \x -> [ o | o@SchemaCacheQueriedObs{} <- pure x ]
+        waitFor (1 * sec) "SchemaCacheLoadedObs" $ \x -> [ o | o@SchemaCacheLoadedObs{} <- pure x ]
+  where
+    sec = 1000000