bump version to 12.2.2

Fixes https://github.com/PostgREST/postgrest/issues/3523.

Now if there's a failure when obtaining the pg version OR schema cache,
we do the same retrying process. This way we don't add two retries.

Refactors and renames the "connectionWorker" to "schemaCacheLoader".
This makes more sense since what we really want is the schema cache,
the version is the pre-requisite for ensuring our
schema cache queries work.

Additionally, we no longer log ` Attempting to connect to the database...`
at startup unnecessarily. This is only logged whenever there's a retry attempt.

.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@65462800fd760344b1a7b4382951275a0abb4808 # v4.3.3
+      uses: actions/upload-artifact@0b2256b8c012f0828dc542b3febcab082c67f72b # v4.3.4
       with:
         name: ${{ inputs.upload }}
         path: ${{ steps.download.outputs.artifacts }}

.github/workflows/build.yaml

@@ -42,7 +42,7 @@ jobs:
       - name: Build static executable
         run: nix-build -A postgrestStatic
       - name: Save built executable as artifact
-        uses: actions/upload-artifact@65462800fd760344b1a7b4382951275a0abb4808 # v4.3.3
+        uses: actions/upload-artifact@0b2256b8c012f0828dc542b3febcab082c67f72b # v4.3.4
         with:
           name: postgrest-linux-static-x64
           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@65462800fd760344b1a7b4382951275a0abb4808 # v4.3.3
+        uses: actions/upload-artifact@0b2256b8c012f0828dc542b3febcab082c67f72b # v4.3.4
         with:
           name: postgrest-docker-x64
           path: postgrest-docker.tar.gz
@@ -119,7 +119,7 @@ jobs:
     runs-on: ${{ matrix.runs-on }}
     steps:
       - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
-      - uses: haskell-actions/setup@33585e1a16afa5875e124b0ebc89dd0c2f872c21 # v2.7.3
+      - uses: haskell-actions/setup@ec49483bfc012387b227434aba94f59a6ecd0900 # v2.7.5
         with:
           # This must match the version in stack.yaml's resolver
           ghc-version: 9.6.5
@@ -148,7 +148,7 @@ jobs:
         run: strip result/postgrest*
       - name: Save built executable as artifact
         if: matrix.artifact
-        uses: actions/upload-artifact@65462800fd760344b1a7b4382951275a0abb4808 # v4.3.3
+        uses: actions/upload-artifact@0b2256b8c012f0828dc542b3febcab082c67f72b # v4.3.4
         with:
           name: ${{ matrix.artifact }}
           path: |
@@ -179,7 +179,7 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
-      - uses: haskell-actions/setup@33585e1a16afa5875e124b0ebc89dd0c2f872c21 # v2.7.3
+      - uses: haskell-actions/setup@ec49483bfc012387b227434aba94f59a6ecd0900 # v2.7.5
         with:
           ghc-version: ${{ matrix.ghc }}
       - name: Cache .cabal

.github/workflows/ci.yaml

@@ -99,7 +99,7 @@ jobs:
       - name: Extract downloaded binaries
         run: tar -xvf result.tar.xz && rm result.tar.xz
       - name: Save aarch64 executable as artifact
-        uses: actions/upload-artifact@65462800fd760344b1a7b4382951275a0abb4808 # v4.3.3
+        uses: actions/upload-artifact@0b2256b8c012f0828dc542b3febcab082c67f72b # v4.3.4
         with:
           name: postgrest-ubuntu-aarch64
           path: result/postgrest
@@ -183,7 +183,7 @@ jobs:
           echo "Relevant extract from CHANGELOG.md:"
           cat CHANGES.md
       - name: Save CHANGES.md as artifact
-        uses: actions/upload-artifact@65462800fd760344b1a7b4382951275a0abb4808 # v4.3.3
+        uses: actions/upload-artifact@0b2256b8c012f0828dc542b3febcab082c67f72b # v4.3.4
         with:
           name: release-changes
           path: CHANGES.md
@@ -201,7 +201,7 @@ jobs:
     steps:
       - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
       - name: Download all artifacts
-        uses: actions/download-artifact@65a9edc5881444af0b9093a5e628f2fe47ea3b2e # v4.1.7
+        uses: actions/download-artifact@fa0a91b85d4f404e444e00e005971372dc801d16 # v4.1.8
         with:
           path: artifacts
       - name: Create release bundle with archives for all builds
@@ -226,7 +226,7 @@ jobs:
             artifacts/postgrest-windows-x64/postgrest.exe
 
       - name: Save release bundle
-        uses: actions/upload-artifact@65462800fd760344b1a7b4382951275a0abb4808 # v4.3.3
+        uses: actions/upload-artifact@0b2256b8c012f0828dc542b3febcab082c67f72b # v4.3.4
         with:
           name: release-bundle
           path: release-bundle
@@ -275,7 +275,7 @@ jobs:
     steps:
       - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
       - name: Download Docker image
-        uses: actions/download-artifact@65a9edc5881444af0b9093a5e628f2fe47ea3b2e # v4.1.7
+        uses: actions/download-artifact@fa0a91b85d4f404e444e00e005971372dc801d16 # v4.1.8
         with:
           name: postgrest-docker-x64
       - name: Publish images on Docker Hub

.github/workflows/report.yaml

@@ -21,7 +21,7 @@ jobs:
     if: github.event.workflow_run.conclusion == 'success' || github.event.workflow_run.conclusion == 'failure'
     steps:
       - name: Download from Artifacts
-        uses: actions/download-artifact@65a9edc5881444af0b9093a5e628f2fe47ea3b2e # v4.1.7
+        uses: actions/download-artifact@fa0a91b85d4f404e444e00e005971372dc801d16 # v4.1.8
         with:
           github-token: ${{ github.token }}
           run-id: ${{ github.event.workflow_run.id }}

.github/workflows/test.yaml

@@ -131,7 +131,7 @@ jobs:
           postgrest-loadtest-against main ${{ steps.get-latest-tag.outputs.tag }}
           postgrest-loadtest-report > loadtest/loadtest.md
       - name: Upload report
-        uses: actions/upload-artifact@65462800fd760344b1a7b4382951275a0abb4808 # v4.3.3
+        uses: actions/upload-artifact@0b2256b8c012f0828dc542b3febcab082c67f72b # v4.3.4
         with:
           name: loadtest.md
           path: loadtest/loadtest.md

CHANGELOG.md

@@ -5,6 +5,16 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ## Unreleased
 
+## [12.2.2] - 2024-07-10
+
+### Fixed
+
+ - #3093, Nested empty embeds no longer show empty values and are correctly omitted - @laurenceisla
+ - #3644, Make --dump-schema work with in-database pgrst.db_schemas setting - @wolfgangwalther
+ - #3644, Show number of timezones in schema cache load report - @wolfgangwalther
+ - #3644, List correct enum options in OpenApi output when multiple types with same name are present - @wolfgangwalther
+ - #3523, Fix schema cache loading retry without backoff - @steve-chavez
+
 ## [12.2.1] - 2024-06-27
 
 ### Fixed

README.md

@@ -1,7 +1,6 @@
 ![Logo](static/postgrest.png "Logo")
 
 [![Donate](https://img.shields.io/badge/Donate-Patreon-orange.svg?colorB=F96854)](https://www.patreon.com/postgrest)
-[![Donate](https://img.shields.io/badge/Donate-PayPal-green.svg)](https://www.paypal.me/postgrest)
 [![Join the chat at https://gitter.im/begriffs/postgrest](https://img.shields.io/badge/gitter-join%20chat%20%E2%86%92-brightgreen.svg)](https://gitter.im/begriffs/postgrest)
 [![Docs](https://img.shields.io/badge/docs-latest-brightgreen.svg?style=flat)](http://postgrest.org)
 [![Docker Stars](https://img.shields.io/docker/pulls/postgrest/postgrest.svg)](https://hub.docker.com/r/postgrest/postgrest/)
@@ -145,11 +144,7 @@ and the [API guide](http://postgrest.org/en/stable/api.html).
 
 ## Supporting development
 
-You can help PostgREST ongoing maintenance and development by:
+You can help PostgREST ongoing maintenance and development by making a regular donation through Patreon https://www.patreon.com/postgrest
-
-- Making a regular donation through Patreon https://www.patreon.com/postgrest
-
-- Alternatively, you can make a one-time donation via Paypal https://www.paypal.me/postgrest
 
 Every donation will be spent on making PostgREST better for the whole community.
 

docker-hub-readme.md

@@ -2,7 +2,6 @@
 
 [![Join the chat at https://gitter.im/begriffs/postgrest](https://img.shields.io/badge/gitter-join%20chat%20%E2%86%92-brightgreen.svg)](https://gitter.im/begriffs/postgrest)
 [![Donate](https://img.shields.io/badge/Donate-Patreon-orange.svg?colorB=F96854)](https://www.patreon.com/postgrest)
-[![Donate](https://img.shields.io/badge/Donate-PayPal-green.svg)](https://www.paypal.me/postgrest)
 [![Docs](https://img.shields.io/badge/docs-latest-brightgreen.svg?style=flat)](http://postgrest.org)
 [![Build Status](https://github.com/postgrest/postgrest/actions/workflows/ci.yaml/badge.svg?branch=main)](https://github.com/PostgREST/postgrest/actions?query=branch%3Amain)
 

docs/index.rst

@@ -22,9 +22,6 @@ PostgREST Documentation
 .. image:: https://img.shields.io/badge/Donate-Patreon-orange.svg?colorB=F96854
   :target: https://www.patreon.com/postgrest
 
-.. image:: https://img.shields.io/badge/Donate-PayPal-green.svg
-  :target: https://www.paypal.com/paypalme/postgrest
-
 |
 
 PostgREST is a standalone web server that turns your PostgreSQL database directly into a RESTful API. The structural constraints and permissions in the database determine the API endpoints and operations.

docs/references/api/tables_views.rst

@@ -82,7 +82,7 @@ cs            :code:`@>`                contains e.g. :code:`?tags=cs.{example,
 cd            :code:`<@`                contained in e.g. :code:`?values=cd.{1,2,3}`
 ov            :code:`&&`                overlap (have points in common), e.g. :code:`?period=ov.[2017-01-01,2017-06-30]` –
                                         also supports array types, use curly braces instead of square brackets e.g.
-                                        :code: `?arr=ov.{1,3}`
+                                        :code:`?arr=ov.{1,3}`
 sl            :code:`<<`                strictly left of, e.g. :code:`?range=sl.(1,10)`
 sr            :code:`>>`                strictly right of
 nxr           :code:`&<`                does not extend to the right of, e.g. :code:`?range=nxr.(1,10)`

postgrest.cabal

@@ -1,5 +1,5 @@
 name:               postgrest
-version:            12.2.1
+version:            12.2.2
 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

src/PostgREST/App.hs

@@ -68,14 +68,14 @@ run appState = do
 
   observer $ AppStartObs prettyVersion
 
-  AppState.connectionWorker appState
+  AppState.schemaCacheLoader appState -- Loads the initial SchemaCache
-  Unix.installSignalHandlers (AppState.getMainThreadId appState) (AppState.connectionWorker appState) (AppState.reReadConfig False appState)
+  Unix.installSignalHandlers (AppState.getMainThreadId appState) (AppState.schemaCacheLoader appState) (AppState.readInDbConfig False appState)
 
   Listener.runListener appState
 
   Admin.runAdmin appState (serverSettings conf)
 
-  let app = postgrest configLogLevel appState (AppState.connectionWorker appState)
+  let app = postgrest configLogLevel appState (AppState.schemaCacheLoader appState)
 
   case configServerUnixSocket of
     Just path -> do

src/PostgREST/AppState.hs

@@ -24,8 +24,8 @@ module PostgREST.AppState
   , putPgVersion
   , putIsListenerOn
   , usePool
-  , reReadConfig
+  , readInDbConfig
-  , connectionWorker
+  , schemaCacheLoader
   , getObserver
   , isLoaded
   , isPending
@@ -85,39 +85,37 @@ data AuthResult = AuthResult
 
 data AppState = AppState
   -- | Database connection pool
-  { statePool                 :: SQL.Pool
+  { statePool              :: SQL.Pool
-  -- | Database server version, will be updated by the connectionWorker
+  -- | Database server version
-  , statePgVersion            :: IORef PgVersion
+  , statePgVersion         :: IORef PgVersion
-  -- | No schema cache at the start. Will be filled in by the connectionWorker
+  -- | Schema cache
-  , stateSchemaCache          :: IORef (Maybe SchemaCache)
+  , stateSchemaCache       :: IORef (Maybe SchemaCache)
   -- | The schema cache status
-  , stateSCacheStatus         :: IORef SchemaCacheStatus
+  , stateSCacheStatus      :: IORef SchemaCacheStatus
-  -- | The connection status
-  , stateConnStatus           :: IORef ConnectionStatus
   -- | State of the LISTEN channel
-  , stateIsListenerOn         :: IORef Bool
+  , stateIsListenerOn      :: IORef Bool
   -- | starts the connection worker with a debounce
-  , debouncedConnectionWorker :: IO ()
+  , debouncedSCacheLoader  :: IO ()
   -- | Config that can change at runtime
-  , stateConf                 :: IORef AppConfig
+  , stateConf              :: IORef AppConfig
   -- | Time used for verifying JWT expiration
-  , stateGetTime              :: IO UTCTime
+  , stateGetTime           :: IO UTCTime
   -- | Used for killing the main thread in case a subthread fails
-  , stateMainThreadId         :: ThreadId
+  , stateMainThreadId      :: ThreadId
   -- | Keeps track of the next delay for db connection retry
-  , stateNextDelay            :: IORef Int
+  , stateNextDelay         :: IORef Int
   -- | Keeps track of the next delay for the listener
-  , stateNextListenerDelay    :: IORef Int
+  , stateNextListenerDelay :: IORef Int
   -- | JWT Cache
-  , jwtCache                  :: C.Cache ByteString AuthResult
+  , jwtCache               :: C.Cache ByteString AuthResult
   -- | Network socket for REST API
-  , stateSocketREST           :: NS.Socket
+  , stateSocketREST        :: NS.Socket
   -- | Network socket for the admin UI
-  , stateSocketAdmin          :: Maybe NS.Socket
+  , stateSocketAdmin       :: Maybe NS.Socket
   -- | Observation handler
-  , stateObserver             :: ObservationHandler
+  , stateObserver          :: ObservationHandler
-  , stateLogger               :: Logger.LoggerState
+  , stateLogger            :: Logger.LoggerState
-  , stateMetrics              :: Metrics.MetricsState
+  , stateMetrics           :: Metrics.MetricsState
   }
 
 -- | Schema cache status
@@ -126,15 +124,8 @@ data SchemaCacheStatus
   | SCPending
   deriving Eq
 
--- | Current database connection status
-data ConnectionStatus
-  = ConnEstablished
-  | ConnPending
-  deriving Eq
-
 type AppSockets = (NS.Socket, Maybe NS.Socket)
 
-
 init :: AppConfig -> IO AppState
 init conf@AppConfig{configLogLevel, configDbPoolSize} = do
   loggerState  <- Logger.init
@@ -153,7 +144,6 @@ initWithPool (sock, adminSock) pool conf loggerState metricsState observer = do
     <$> newIORef minimumPgVersion -- assume we're in a supported version when starting, this will be corrected on a later step
     <*> newIORef Nothing
     <*> newIORef SCPending
-    <*> newIORef ConnPending
     <*> newIORef False
     <*> pure (pure ())
     <*> newIORef conf
@@ -168,15 +158,15 @@ initWithPool (sock, adminSock) pool conf loggerState metricsState observer = do
     <*> pure loggerState
     <*> pure metricsState
 
-  debWorker <-
+  deb <-
     let decisecond = 100000 in
     mkDebounce defaultDebounceSettings
-       { debounceAction = internalConnectionWorker appState
+       { debounceAction = internalSchemaCacheLoad appState
        , debounceFreq = decisecond
        , debounceEdge = leadingEdge -- runs the worker at the start and the end
        }
 
-  return appState { debouncedConnectionWorker = debWorker}
+  return appState { debouncedSCacheLoader = deb}
 
 destroy :: AppState -> IO ()
 destroy = destroyPool
@@ -302,15 +292,12 @@ getSchemaCache = readIORef . stateSchemaCache
 putSchemaCache :: AppState -> Maybe SchemaCache -> IO ()
 putSchemaCache appState = atomicWriteIORef (stateSchemaCache appState)
 
-connectionWorker :: AppState -> IO ()
+schemaCacheLoader :: AppState -> IO ()
-connectionWorker = debouncedConnectionWorker
+schemaCacheLoader = debouncedSCacheLoader
 
 getNextDelay :: AppState -> IO Int
 getNextDelay = readIORef . stateNextDelay
 
-putNextDelay :: AppState -> Int -> IO ()
-putNextDelay = atomicWriteIORef . stateNextDelay
-
 getNextListenerDelay :: AppState -> IO Int
 getNextListenerDelay = readIORef . stateNextListenerDelay
 
@@ -338,167 +325,120 @@ getSocketAdmin = stateSocketAdmin
 getMainThreadId :: AppState -> ThreadId
 getMainThreadId = stateMainThreadId
 
-getIsListenerOn :: AppState -> IO Bool
+isConnEstablished :: AppState -> IO Bool
-getIsListenerOn appState = do
+isConnEstablished appState = do
   AppConfig{..} <- getConfig appState
-  if configDbChannelEnabled then
+  if configDbChannelEnabled then -- if the listener is enabled, we can be sure the connection is up
     readIORef $ stateIsListenerOn appState
-  else
+  else -- otherwise the only way to check the connection is to make a query
-    pure True
+    isRight <$> usePool appState (SQL.sql "SELECT 1")
 
 putIsListenerOn :: AppState -> Bool -> IO ()
 putIsListenerOn = atomicWriteIORef . stateIsListenerOn
 
-isConnEstablished :: AppState -> IO Bool
-isConnEstablished x = do
-  conf <- getConfig x
-  if configDbChannelEnabled conf
-    then do -- if the listener is enabled, we can be sure the connection status is always up to date
-      st <- readIORef $ stateConnStatus x
-      return $ st == ConnEstablished
-    else    -- otherwise the only way to check the connection is to make a query
-      isRight <$> usePool x (SQL.sql "SELECT 1")
-
 isLoaded :: AppState -> IO Bool
 isLoaded x = do
   scacheStatus <- readIORef $ stateSCacheStatus x
   connEstablished <- isConnEstablished x
-  listenerOn <- getIsListenerOn x
+  return $ scacheStatus == SCLoaded && connEstablished
-  return $ scacheStatus == SCLoaded && connEstablished && listenerOn
 
 isPending :: AppState -> IO Bool
 isPending x = do
   scacheStatus <- readIORef $ stateSCacheStatus x
-  connStatus <- readIORef $ stateConnStatus x
+  connEstablished <- isConnEstablished x
-  listenerOn <- getIsListenerOn x
+  return $ scacheStatus == SCPending || not connEstablished
-  return $ scacheStatus == SCPending || connStatus == ConnPending || not listenerOn
 
 putSCacheStatus :: AppState -> SchemaCacheStatus -> IO ()
 putSCacheStatus = atomicWriteIORef . stateSCacheStatus
 
-putConnStatus :: AppState -> ConnectionStatus -> IO ()
-putConnStatus = atomicWriteIORef . stateConnStatus
-
 getObserver :: AppState -> ObservationHandler
 getObserver = stateObserver
 
--- | Load the SchemaCache by using a connection from the pool.
+internalSchemaCacheLoad :: AppState -> IO ()
-loadSchemaCache :: AppState -> IO SchemaCacheStatus
+internalSchemaCacheLoad appState = do
-loadSchemaCache appState@AppState{stateObserver=observer} = do
+  AppConfig{..} <- getConfig appState
-  conf@AppConfig{..} <- getConfig appState
+  void $ retryingSchemaCacheLoad appState
-  (resultTime, result) <-
+  -- We cannot retry reading the in-db config after it fails immediately, because it could have user errors. We just report the error and continue.
-    let transaction = if configDbPreparedStatements then SQL.transaction else SQL.unpreparedTransaction in
+  when configDbConfig $ readInDbConfig False appState
-    timeItT $ usePool appState (transaction SQL.ReadCommitted SQL.Read $ querySchemaCache conf)
-  case result of
-    Left e -> do
-      putSCacheStatus appState SCPending
-      putSchemaCache appState Nothing
-      observer $ SchemaCacheErrorObs e
-      return SCPending
 
-    Right sCache -> do
+-- | Try to load the schema cache and retry if it fails.
-      -- IMPORTANT: While the pending schema cache state starts from running the above querySchemaCache, only at this stage we block API requests due to the usage of an
-      -- 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
-      observer $ SchemaCacheQueriedObs resultTime
-      (t, _) <- timeItT $ observer $ SchemaCacheSummaryObs $ showSummary sCache
-      observer $ SchemaCacheLoadedObs t
-      putSCacheStatus appState SCLoaded
-      return SCLoaded
-
--- | The purpose of this worker is to obtain a healthy connection to pg and an
--- up-to-date schema cache(SchemaCache).  This method is meant to be called
--- multiple times by the same thread, but does nothing if the previous
--- invocation has not terminated. In all cases this method does not halt the
--- calling thread, the work is performed in a separate thread.
 --
--- Background thread that does the following :
+-- This is done by repeatedly: 1) flushing the pool, 2) querying the version and validating that the postgres version is supported by us, and 3) loading the schema cache.
---  1. Tries to connect to pg server and will keep trying until success.
+-- It's necessary to flush the pool:
---  2. Checks if the pg version is supported and if it's not it kills the main
+--
---     program.
+-- + Because connections cache the pg catalog(see #2620)
---  3. Obtains the sCache. If this fails, it goes back to 1.
+-- + For rapid recovery. Otherwise, the pool idle or lifetime timeout would have to be reached for new healthy connections to be acquired.
-internalConnectionWorker :: AppState -> IO ()
+retryingSchemaCacheLoad :: AppState -> IO (Maybe PgVersion, Maybe SchemaCache)
-internalConnectionWorker appState@AppState{stateObserver=observer, stateMainThreadId=mainThreadId} = work
+retryingSchemaCacheLoad appState@AppState{stateObserver=observer, stateMainThreadId=mainThreadId} =
+  retrying retryPolicy shouldRetry (\RetryStatus{rsIterNumber, rsPreviousDelay} -> do
+    when (rsIterNumber > 0) $ do
+      let delay = fromMaybe 0 rsPreviousDelay `div` oneSecondInUs
+      observer $ ConnectionRetryObs delay
+      putNextListenerDelay appState delay
+
+    flushPool appState
+    (,) <$> qPgVersion <*> qSchemaCache
+  )
   where
-    work = do
+    qPgVersion :: IO (Maybe PgVersion)
+    qPgVersion = do
       AppConfig{..} <- getConfig appState
-      observer DBConnectAttemptObs
-      connStatus <- establishConnection appState
-      case connStatus of
-        ConnPending ->
-          unless configDbPoolAutomaticRecovery $ do
-            observer ExitDBNoRecoveryObs
-            killThread mainThreadId
-        ConnEstablished -> do
-          actualPgVersion <- getPgVersion appState
-          when (actualPgVersion < minimumPgVersion) $ do
-            observer $ ExitUnsupportedPgVersion actualPgVersion minimumPgVersion
-            killThread mainThreadId
-          observer (DBConnectedObs $ pgvFullName actualPgVersion)
-          -- this could be fail because the connection drops, but the loadSchemaCache will pick the error and retry again
-          -- We cannot retry after it fails immediately, because db-pre-config could have user errors. We just log the error and continue.
-          when configDbConfig $ reReadConfig False appState
-          scStatus <- loadSchemaCache appState
-          case scStatus of
-            SCLoaded ->
-              -- do nothing and proceed if the load was successful
-              return ()
-            SCPending ->
-              -- retry reloading the schema cache
-              work
-
--- | Repeatedly flush the pool, and check if a connection from the
--- pool allows access to the PostgreSQL database.
---
--- Releasing the pool is key for rapid recovery. Otherwise, the pool
--- timeout would have to be reached for new healthy connections to be acquired.
--- Which might not happen if the server is busy with requests. No idle
--- connection, no pool timeout.
---
--- It's also necessary to release the pool connections because they cache the pg catalog(see #2620)
---
--- The connection tries are capped, but if the connection times out no error is
--- thrown, just 'False' is returned.
-establishConnection :: AppState -> IO ConnectionStatus
-establishConnection appState@AppState{stateObserver=observer} =
-  retrying retryPolicy shouldRetry $
-    const $ flushPool appState >> getConnectionStatus
-  where
-    getConnectionStatus :: IO ConnectionStatus
-    getConnectionStatus = do
       pgVersion <- usePool appState (queryPgVersion False) -- No need to prepare the query here, as the connection might not be established
       case pgVersion of
         Left e -> do
-          observer $ ConnectionPgVersionErrorObs e
+          observer $ QueryPgVersionError e
-          putConnStatus appState ConnPending
+          unless configDbPoolAutomaticRecovery $ do
-          return ConnPending
+            observer ExitDBNoRecoveryObs
-        Right version -> do
+            killThread mainThreadId
-          putConnStatus appState ConnEstablished
+          return Nothing
-          putPgVersion appState version
+        Right actualPgVersion -> do
-          return ConnEstablished
+          when (actualPgVersion < minimumPgVersion) $ do
+            observer $ ExitUnsupportedPgVersion actualPgVersion minimumPgVersion
+            killThread mainThreadId
+          observer $ DBConnectedObs $ pgvFullName actualPgVersion
+          putPgVersion appState actualPgVersion
+          return $ Just actualPgVersion
 
-    shouldRetry :: RetryStatus -> ConnectionStatus -> IO Bool
+    qSchemaCache :: IO (Maybe SchemaCache)
-    shouldRetry rs isConnSucc = do
+    qSchemaCache = do
+      conf@AppConfig{..} <- getConfig appState
+      (resultTime, result) <-
+        let transaction = if configDbPreparedStatements then SQL.transaction else SQL.unpreparedTransaction in
+        timeItT $ usePool appState (transaction SQL.ReadCommitted SQL.Read $ querySchemaCache conf)
+      case result of
+        Left e -> do
+          putSCacheStatus appState SCPending
+          putSchemaCache appState Nothing
+          observer $ SchemaCacheErrorObs e
+          return Nothing
+
+        Right sCache -> do
+          -- IMPORTANT: While the pending schema cache state starts from running the above querySchemaCache, only at this stage we block API requests due to the usage of an
+          -- 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
+          observer $ SchemaCacheQueriedObs resultTime
+          (t, _) <- timeItT $ observer $ SchemaCacheSummaryObs $ showSummary sCache
+          observer $ SchemaCacheLoadedObs t
+          putSCacheStatus appState SCLoaded
+          return $ Just sCache
+
+    shouldRetry :: RetryStatus -> (Maybe PgVersion, Maybe SchemaCache) -> IO Bool
+    shouldRetry _ (pgVer, sCache) = do
       AppConfig{..} <- getConfig appState
-      let
+      let itShould = configDbPoolAutomaticRecovery && (isNothing pgVer || isNothing sCache)
-        delay = fromMaybe 0 (rsPreviousDelay rs) `div` oneSecondInUs
-        itShould = ConnPending == isConnSucc && configDbPoolAutomaticRecovery
-      when itShould $ observer $ ConnectionRetryObs delay
-      when itShould $ putNextDelay appState delay
       return itShould
 
     retryPolicy :: RetryPolicy
     retryPolicy =
-      let
+      let delayMicroseconds = 32*oneSecondInUs {-32 seconds-} in
-        delayMicroseconds = 32000000 -- 32 seconds
-      in
       capDelay delayMicroseconds $ exponentialBackoff oneSecondInUs
-    oneSecondInUs = 1000000 -- | One second in microseconds
 
--- | Re-reads the config plus config options from the db
+    oneSecondInUs = 1000000 -- one second in microseconds
-reReadConfig :: Bool -> AppState -> IO ()
+
-reReadConfig startingUp appState@AppState{stateObserver=observer} = do
+-- | Reads the in-db config and reads the config file again
+readInDbConfig :: Bool -> AppState -> IO ()
+readInDbConfig startingUp appState@AppState{stateObserver=observer} = do
   AppConfig{..} <- getConfig appState
   pgVer <- getPgVersion appState
   dbSettings <-

src/PostgREST/CLI.hs

@@ -42,9 +42,11 @@ main CLI{cliCommand, cliPath} = do
     AppState.destroy
     (\appState -> case cliCommand of
       CmdDumpConfig -> do
-        when configDbConfig $ AppState.reReadConfig True appState
+        when configDbConfig $ AppState.readInDbConfig True appState
         putStr . Config.toText =<< AppState.getConfig appState
-      CmdDumpSchema -> putStrLn =<< dumpSchema appState
+      CmdDumpSchema -> do
+        when configDbConfig $ AppState.readInDbConfig True appState
+        putStrLn =<< dumpSchema appState
       CmdRun -> App.run appState)
 
 -- | Dump SchemaCache schema to JSON

src/PostgREST/Listener.hs

@@ -54,8 +54,8 @@ retryingListen appState = do
 
         delay <- AppState.getNextListenerDelay appState
         when (delay > 1) $ do -- if we did a retry
-          -- assume we lost notifications, call the connection worker which will also reload the schema cache
+          -- assume we lost notifications, refresh the schema cache
-          AppState.connectionWorker appState
+          AppState.schemaCacheLoader appState
           -- reset the delay
           AppState.putNextListenerDelay appState 1
 
@@ -74,8 +74,8 @@ retryingListen appState = do
     handleNotification channel msg =
       if | BS.null msg            -> observer (DBListenerGotSCacheMsg channel) >> cacheReloader
          | msg == "reload schema" -> observer (DBListenerGotSCacheMsg channel) >> cacheReloader
-         | msg == "reload config" -> observer (DBListenerGotConfigMsg channel) >> AppState.reReadConfig False appState
+         | msg == "reload config" -> observer (DBListenerGotConfigMsg channel) >> AppState.readInDbConfig False appState
          | otherwise              -> pure () -- Do nothing if anything else than an empty message is sent
 
     cacheReloader =
-      AppState.connectionWorker appState
+      AppState.schemaCacheLoader appState

src/PostgREST/Observation.hs

@@ -29,7 +29,6 @@ data Observation
   | AppStartObs ByteString
   | AppServerPortObs NS.PortNumber
   | AppServerUnixObs FilePath
-  | DBConnectAttemptObs
   | ExitUnsupportedPgVersion PgVersion PgVersion
   | ExitDBNoRecoveryObs
   | ExitDBFatalError ObsFatalError SQL.UsageError
@@ -39,7 +38,6 @@ data Observation
   | SchemaCacheSummaryObs Text
   | SchemaCacheLoadedObs Double
   | ConnectionRetryObs Int
-  | ConnectionPgVersionErrorObs SQL.UsageError
   | DBListenStart Text
   | DBListenFail Text (Either SQL.ConnectionError (Either SomeException ()))
   | DBListenRetry Int
@@ -50,6 +48,7 @@ data Observation
   | ConfigSucceededObs
   | QueryRoleSettingsErrorObs SQL.UsageError
   | QueryErrorCodeHighObs SQL.UsageError
+  | QueryPgVersionError SQL.UsageError
   | PoolAcqTimeoutObs SQL.UsageError
   | HasqlPoolObs SQL.Observation
   | PoolRequest
@@ -69,8 +68,6 @@ observationMessage = \case
     "Listening on port " <> show port
   AppServerUnixObs sock ->
     "Listening on unix socket " <> show sock
-  DBConnectAttemptObs ->
-    "Attempting to connect to the database..."
   DBConnectedObs ver ->
     "Successfully connected to " <> ver
   ExitUnsupportedPgVersion pgVer minPgVer ->
@@ -78,7 +75,7 @@ observationMessage = \case
   ExitDBNoRecoveryObs ->
     "Automatic recovery disabled, exiting."
   ExitDBFatalError ServerAuthError usageErr ->
-    jsonMessage usageErr
+    "Failed to establish a connection. " <> jsonMessage usageErr
   ExitDBFatalError ServerPgrstBug usageErr ->
     "This is probably a bug in PostgREST, please report it at https://github.com/PostgREST/postgrest/issues. " <> jsonMessage usageErr
   ExitDBFatalError ServerError42P05 usageErr ->
@@ -95,8 +92,8 @@ observationMessage = \case
     "Schema cache loaded in " <> showMillis resultTime <> " milliseconds"
   ConnectionRetryObs delay ->
     "Attempting to reconnect to the database in " <> (show delay::Text) <> " seconds..."
-  ConnectionPgVersionErrorObs usageErr ->
+  QueryPgVersionError usageErr ->
-    jsonMessage usageErr
+    "Failed to query the PostgreSQL version. " <> jsonMessage usageErr
   DBListenStart channel -> do
     "Listening for notifications on the " <> show channel <> " channel"
   DBListenFail channel listenErr ->

src/PostgREST/Plan.hs

@@ -622,7 +622,11 @@ generateRelSelectField (Node ReadPlan{relToParent=Just rel, select, relName, rel
   where
     rsSelName = fromMaybe relName relAlias
     rsEmbedMode = if relIsToOne rel then JsonObject else JsonArray
-    rsEmptyEmbed = null select && null forest
+    rsEmptyEmbed = hasOnlyNullEmbed (null select) forest
+    hasOnlyNullEmbed = foldr checkIfNullEmbed
+    checkIfNullEmbed :: ReadPlanTree -> Bool -> Bool
+    checkIfNullEmbed (Node ReadPlan{select=s} f) isNullEmbed =
+      isNullEmbed && hasOnlyNullEmbed (null s) f
 generateRelSelectField _ = Nothing
 
 generateSpreadSelectFields :: ReadPlan -> [SpreadSelectField]

src/PostgREST/SchemaCache.hs

@@ -95,13 +95,14 @@ instance JSON.ToJSON SchemaCache where
     ]
 
 showSummary :: SchemaCache -> Text
-showSummary (SchemaCache tbls rels routs reps mediaHdlrs _) =
+showSummary (SchemaCache tbls rels routs reps mediaHdlrs tzs) =
   T.intercalate ", "
   [ show (HM.size tbls)       <> " Relations"
   , show (HM.size rels)       <> " Relationships"
   , show (HM.size routs)      <> " Functions"
   , show (HM.size reps)       <> " Domain Representations"
   , show (HM.size mediaHdlrs) <> " Media Type Handlers"
+  , show (S.size tzs)         <> " Timezones"
   ]
 
 -- | A view foreign key or primary key dependency detected on its source table
@@ -646,7 +647,7 @@ tablesSqlQuery pgVer =
               information_schema._pg_truetypid(a.*, t.*),
               information_schema._pg_truetypmod(a.*, t.*)
           )::integer AS character_maximum_length,
-          COALESCE(bt.typname, t.typname)::name AS udt_name,
+          COALESCE(bt.oid, t.oid) AS base_type,
           a.attnum::integer AS position
       FROM pg_attribute a
           LEFT JOIN pg_description AS d
@@ -690,14 +691,13 @@ tablesSqlQuery pgVer =
     FROM columns info
     LEFT OUTER JOIN (
         SELECT
-            n.nspname AS s,
+            e.enumtypid,
-            t.typname AS n,
             array_agg(e.enumlabel ORDER BY e.enumsortorder) AS vals
         FROM pg_type t
         JOIN pg_enum e ON t.oid = e.enumtypid
         JOIN pg_namespace n ON n.oid = t.typnamespace
-        GROUP BY s,n
+        GROUP BY enumtypid
-    ) AS enum_info ON info.udt_name = enum_info.n
+    ) AS enum_info ON info.base_type = enum_info.enumtypid
     WHERE info.table_schema NOT IN ('pg_catalog', 'information_schema')
     GROUP BY info.table_schema, info.table_name
   ),

test/io/test_io.py

@@ -778,7 +778,7 @@ def test_metrics_include_schema_cache_fails(defaultenv, metapostgrest):
                 r'pgrst_schema_cache_loads_total{status="FAIL"} (\d+)', response.text
             ).group(1)
         )
-        assert metrics > 3.0
+        assert metrics == 1.0
 
     reset_statement_timeout(metapostgrest, role)
 

test/spec/Feature/Query/QuerySpec.hs

@@ -1218,6 +1218,20 @@ spec actualPgVersion = do
         [json|[{"id":1,"name":"Angela Martin"}]|]
         { matchHeaders = [matchContentTypeJson] }
 
+    it "works on nested relationships" $ do
+      get "/users?select=*,users_tasks(tasks(projects()))" `shouldRespondWith`
+        [json| [{"id":1,"name":"Angela Martin"}, {"id":2,"name":"Michael Scott"}, {"id":3,"name":"Dwight Schrute"}]|]
+        { matchHeaders = [matchContentTypeJson] }
+      get "/users?select=*,users_tasks!inner(tasks!inner(projects()))&users_tasks.tasks.id=eq.3" `shouldRespondWith`
+        [json| [{"id":1,"name":"Angela Martin"}]|]
+        { matchHeaders = [matchContentTypeJson] }
+      get "/users?select=*,tasks(projects(clients()),users_tasks())" `shouldRespondWith`
+        [json| [{"id":1,"name":"Angela Martin"}, {"id":2,"name":"Michael Scott"}, {"id":3,"name":"Dwight Schrute"}]|]
+        { matchHeaders = [matchContentTypeJson] }
+      get "/users?select=*,tasks!inner(projects(clients()),users_tasks(),name)&tasks.id=eq.3" `shouldRespondWith`
+        [json| [{"id":1,"name":"Angela Martin","tasks":[{"name": "Design w10"}]}]|]
+        { matchHeaders = [matchContentTypeJson] }
+
   context "empty root select" $
     it "gives all columns" $ do
       get "/projects?select=" `shouldRespondWith`
@@ -1413,4 +1427,3 @@ spec actualPgVersion = do
       get "/infinite_recursion?select=*" `shouldRespondWith`
         [json|{"code":"42P17","message":"infinite recursion detected in rules for relation \"infinite_recursion\"","details":null,"hint":null}|]
         { matchStatus = 500 }
-