Explicitly invalidate enum values when metadata is reloaded

This fixes #3759. Also, while we’re at it, also improve the way
invalidations are synced across instances so enums and remote schemas
are appropriately reloaded by the schema syncing process.

server/src-exec/Main.hs

@@ -46,7 +46,7 @@ runApp (HGEOptionsG rci hgeCmd) =
         execQuery queryBs
           & runHasSystemDefinedT (SystemDefined False)
           & runCacheRWT schemaCache
-          & fmap fst
+          & fmap (\(res, _, _) -> res)
       either printErrJExit (liftIO . BLC.putStrLn) res
 
     HCVersion -> liftIO $ putStrLn $ "Hasura GraphQL Engine: " ++ convertText currentVersion

server/src-lib/Hasura/RQL/DDL/Metadata.hs

@@ -380,7 +380,7 @@ runExportMetadata _ =
 
 runReloadMetadata :: (QErrM m, CacheRWM m) => ReloadMetadata -> m EncJSON
 runReloadMetadata ReloadMetadata = do
-  buildSchemaCache
+  buildSchemaCacheWithOptions CatalogUpdate mempty { ciMetadata = True }
   return successMsg
 
 runDumpInternalState

server/src-lib/Hasura/RQL/DDL/RemoteSchema.hs

@@ -13,6 +13,7 @@ import           Hasura.Prelude
 
 import qualified Data.Aeson                  as J
 import qualified Data.HashMap.Strict         as Map
+import qualified Data.HashSet                as S
 import qualified Database.PG.Query           as Q
 
 import           Hasura.GraphQL.RemoteServer
@@ -87,8 +88,8 @@ runReloadRemoteSchema (RemoteSchemaNameQuery name) = do
   void $ onNothing (Map.lookup name rmSchemas) $
     throw400 NotExists $ "remote schema with name " <> name <<> " does not exist"
 
-  invalidateCachedRemoteSchema name
-  withNewInconsistentObjsCheck buildSchemaCache
+  let invalidations = mempty { ciRemoteSchemas = S.singleton name }
+  withNewInconsistentObjsCheck $ buildSchemaCacheWithOptions CatalogUpdate invalidations
   pure successMsg
 
 addRemoteSchemaToCatalog

server/src-lib/Hasura/RQL/DDL/Schema/Cache.hs

@@ -66,39 +66,45 @@ buildRebuildableSchemaCache = do
   pure $ RebuildableSchemaCache (Inc.result result) initialInvalidationKeys (Inc.rebuildRule result)
 
 newtype CacheRWT m a
-  = CacheRWT { unCacheRWT :: StateT (RebuildableSchemaCache m) m a }
+  -- The CacheInvalidations component of the state could actually be collected using WriterT, but
+  -- WriterT implementations prior to transformers-0.5.6.0 (which added
+  -- Control.Monad.Trans.Writer.CPS) are leaky, and we don’t have that yet.
+  = CacheRWT (StateT (RebuildableSchemaCache m, CacheInvalidations) m a)
   deriving
-    ( Functor, Applicative, Monad, MonadIO, MonadReader r, MonadError e, MonadWriter w, MonadTx
+    ( Functor, Applicative, Monad, MonadIO, MonadReader r, MonadError e, MonadTx
     , UserInfoM, HasHttpManager, HasSQLGenCtx, HasSystemDefined )
 
-runCacheRWT :: RebuildableSchemaCache m -> CacheRWT m a -> m (a, RebuildableSchemaCache m)
-runCacheRWT cache = flip runStateT cache . unCacheRWT
+runCacheRWT
+  :: Functor m
+  => RebuildableSchemaCache m -> CacheRWT m a -> m (a, RebuildableSchemaCache m, CacheInvalidations)
+runCacheRWT cache (CacheRWT m) =
+  runStateT m (cache, mempty) <&> \(v, (newCache, invalidations)) -> (v, newCache, invalidations)
 
 instance MonadTrans CacheRWT where
   lift = CacheRWT . lift
 
 instance (Monad m) => TableCoreInfoRM (CacheRWT m)
 instance (Monad m) => CacheRM (CacheRWT m) where
-  askSchemaCache = CacheRWT $ gets lastBuiltSchemaCache
+  askSchemaCache = CacheRWT $ gets (lastBuiltSchemaCache . fst)
 
 instance (MonadIO m, MonadTx m) => CacheRWM (CacheRWT m) where
-  buildSchemaCacheWithOptions buildReason = CacheRWT do
-    RebuildableSchemaCache _ invalidationKeys rule <- get
+  buildSchemaCacheWithOptions buildReason invalidations = CacheRWT do
+    (RebuildableSchemaCache _ invalidationKeys rule, oldInvalidations) <- get
+    let newInvalidationKeys = invalidateKeys invalidations invalidationKeys
     catalogMetadata <- liftTx fetchCatalogData
-    result <- lift $ flip runReaderT buildReason $ Inc.build rule (catalogMetadata, invalidationKeys)
+    result <- lift $ flip runReaderT buildReason $
+      Inc.build rule (catalogMetadata, newInvalidationKeys)
     let schemaCache = Inc.result result
-        prunedInvalidationKeys = pruneInvalidationKeys schemaCache invalidationKeys
-    put $! RebuildableSchemaCache schemaCache prunedInvalidationKeys (Inc.rebuildRule result)
+        prunedInvalidationKeys = pruneInvalidationKeys schemaCache newInvalidationKeys
+        !newCache = RebuildableSchemaCache schemaCache prunedInvalidationKeys (Inc.rebuildRule result)
+        !newInvalidations = oldInvalidations <> invalidations
+    put (newCache, newInvalidations)
     where
       -- Prunes invalidation keys that no longer exist in the schema to avoid leaking memory by
       -- hanging onto unnecessary keys.
       pruneInvalidationKeys schemaCache = over ikRemoteSchemas $ M.filterWithKey \name _ ->
         M.member name (scRemoteSchemas schemaCache)
 
-  invalidateCachedRemoteSchema name =
-    CacheRWT $ modifying (rscInvalidationMap . ikRemoteSchemas . at name) $
-      Just . maybe Inc.initialInvalidationKey Inc.invalidate
-
 buildSchemaCacheRule
   -- Note: by supplying BuildReason via MonadReader, it does not participate in caching, which is
   -- what we want!
@@ -145,7 +151,7 @@ buildSchemaCacheRule = proc (catalogMetadata, invalidationKeys) -> do
             computedFields = catalogMetadata
 
       -- tables
-      tableRawInfos <- buildTableCache -< tables
+      tableRawInfos <- buildTableCache -< (tables, Inc.selectD #_ikMetadata invalidationKeys)
 
       -- relationships and computed fields
       let relationshipsByTable = M.groupOn _crTable relationships

server/src-lib/Hasura/RQL/DDL/Schema/Cache/Common.hs

@@ -1,4 +1,5 @@
 {-# LANGUAGE Arrows          #-}
+{-# LANGUAGE RecordWildCards #-}
 
 -- | Types/functions shared between modules that implement "Hasura.RQL.DDL.Schema.Cache". Other
 -- modules should not import this module directly.
@@ -6,6 +7,7 @@ module Hasura.RQL.DDL.Schema.Cache.Common where
 
 import           Hasura.Prelude
 
+import qualified Data.HashMap.Strict              as M
 import qualified Data.HashSet                     as HS
 import qualified Data.Sequence                    as Seq
 
@@ -20,11 +22,10 @@ import           Hasura.RQL.Types.QueryCollection
 import           Hasura.RQL.Types.Run
 import           Hasura.SQL.Types
 
+-- | 'InvalidationKeys' used to apply requested 'CacheInvalidations'.
 data InvalidationKeys = InvalidationKeys
   { _ikMetadata      :: !Inc.InvalidationKey
-  -- ^ Invalidated by the @reload_metadata@ API.
   , _ikRemoteSchemas :: !(HashMap RemoteSchemaName Inc.InvalidationKey)
-  -- ^ Invalidated by the @reload_remote_schema@ API.
   } deriving (Eq, Generic)
 instance Inc.Cacheable InvalidationKeys
 instance Inc.Select InvalidationKeys
@@ -33,6 +34,13 @@ $(makeLenses ''InvalidationKeys)
 initialInvalidationKeys :: InvalidationKeys
 initialInvalidationKeys = InvalidationKeys Inc.initialInvalidationKey mempty
 
+invalidateKeys :: CacheInvalidations -> InvalidationKeys -> InvalidationKeys
+invalidateKeys CacheInvalidations{..} InvalidationKeys{..} = InvalidationKeys
+  { _ikMetadata = if ciMetadata then Inc.invalidate _ikMetadata else _ikMetadata
+  , _ikRemoteSchemas = foldl' (flip invalidateRemoteSchema) _ikRemoteSchemas ciRemoteSchemas }
+  where
+    invalidateRemoteSchema = M.alter $ Just . maybe Inc.initialInvalidationKey Inc.invalidate
+
 data BuildInputs
   = BuildInputs
   { _biReason          :: !BuildReason

server/src-lib/Hasura/RQL/DDL/Schema/Table.hs

@@ -292,10 +292,14 @@ buildTableCache
   :: forall arr m
    . ( ArrowChoice arr, Inc.ArrowDistribute arr, ArrowWriter (Seq CollectedInfo) arr
      , Inc.ArrowCache m arr, MonadTx m )
-  => [CatalogTable] `arr` M.HashMap QualifiedTable TableRawInfo
-buildTableCache = Inc.cache proc catalogTables -> do
+  => ( [CatalogTable]
+     , Inc.Dependency Inc.InvalidationKey
+     ) `arr` M.HashMap QualifiedTable TableRawInfo
+buildTableCache = Inc.cache proc (catalogTables, reloadMetadataInvalidationKey) -> do
   rawTableInfos <-
-    (| Inc.keyed (| withTable (\tables -> buildRawTableInfo <<< noDuplicateTables -< tables) |)
+    (| Inc.keyed (| withTable (\tables
+         -> (tables, reloadMetadataInvalidationKey)
+         >- first noDuplicateTables >>> buildRawTableInfo) |)
     |) (M.groupOnNE _ctName catalogTables)
   let rawTableCache = M.catMaybes rawTableInfos
       enumTables = flip M.mapMaybe rawTableCache \rawTableInfo ->
@@ -314,8 +318,13 @@ buildTableCache = Inc.cache proc catalogTables -> do
       _           -> throwA -< err400 AlreadyExists "duplication definition for table"
 
     -- Step 1: Build the raw table cache from metadata information.
-    buildRawTableInfo :: ErrorA QErr arr CatalogTable (TableCoreInfoG PGRawColumnInfo PGCol)
-    buildRawTableInfo = Inc.cache proc (CatalogTable name systemDefined isEnum config maybeInfo) -> do
+    buildRawTableInfo
+      :: ErrorA QErr arr
+       ( CatalogTable
+       , Inc.Dependency Inc.InvalidationKey
+       ) (TableCoreInfoG PGRawColumnInfo PGCol)
+    buildRawTableInfo = Inc.cache proc (catalogTable, reloadMetadataInvalidationKey) -> do
+      let CatalogTable name systemDefined isEnum config maybeInfo = catalogTable
       catalogInfo <-
         (| onNothingA (throwA -<
              err400 NotExists $ "no such table/view exists in postgres: " <>> name)
@@ -326,7 +335,11 @@ buildTableCache = Inc.cache proc catalogTables -> do
           primaryKey = _ctiPrimaryKey catalogInfo
       rawPrimaryKey <- liftEitherA -< traverse (resolvePrimaryKeyColumns columnMap) primaryKey
       enumValues <- if isEnum
-        then bindErrorA -< Just <$> fetchAndValidateEnumValues name rawPrimaryKey columns
+        then do
+          -- We want to make sure we reload enum values whenever someone explicitly calls
+          -- `reload_metadata`.
+          Inc.dependOn -< reloadMetadataInvalidationKey
+          bindErrorA -< Just <$> fetchAndValidateEnumValues name rawPrimaryKey columns
         else returnA -< Nothing
 
       returnA -< TableCoreInfo

server/src-lib/Hasura/RQL/Types/SchemaCache/Build.hs

@@ -13,6 +13,7 @@ module Hasura.RQL.Types.SchemaCache.Build
 
   , CacheRWM(..)
   , BuildReason(..)
+  , CacheInvalidations(..)
   , buildSchemaCache
   , buildSchemaCacheFor
   , buildSchemaCacheStrict
@@ -28,6 +29,8 @@ import qualified Data.Text                     as T
 import           Control.Arrow.Extended
 import           Control.Lens
 import           Data.Aeson                    (toJSON)
+import           Data.Aeson.Casing
+import           Data.Aeson.TH
 import           Data.List                     (nub)
 
 import           Hasura.RQL.Types.Error
@@ -96,8 +99,7 @@ withRecordInconsistency f = proc (e, (metadataObject, s)) -> do
 -- operations for triggering a schema cache rebuild
 
 class (CacheRM m) => CacheRWM m where
-  buildSchemaCacheWithOptions :: BuildReason -> m ()
-  invalidateCachedRemoteSchema :: RemoteSchemaName -> m ()
+  buildSchemaCacheWithOptions :: BuildReason -> CacheInvalidations -> m ()
 
 data BuildReason
   -- | The build was triggered by an update this instance made to the catalog (in the
@@ -110,12 +112,26 @@ data BuildReason
   | CatalogSync
   deriving (Show, Eq)
 
+data CacheInvalidations = CacheInvalidations
+  { ciMetadata      :: !Bool
+  -- ^ Force reloading of all database information, including information not technically stored in
+  -- metadata (currently just enum values). Set by the @reload_metadata@ API.
+  , ciRemoteSchemas :: !(HashSet RemoteSchemaName)
+  -- ^ Force refetching of the given remote schemas, even if their definition has not changed. Set
+  -- by the @reload_remote_schema@ API.
+  }
+$(deriveJSON (aesonDrop 2 snakeCase) ''CacheInvalidations)
+
+instance Semigroup CacheInvalidations where
+  CacheInvalidations a1 b1 <> CacheInvalidations a2 b2 = CacheInvalidations (a1 || a2) (b1 <> b2)
+instance Monoid CacheInvalidations where
+  mempty = CacheInvalidations False mempty
+
 instance (CacheRWM m) => CacheRWM (ReaderT r m) where
-  buildSchemaCacheWithOptions = lift . buildSchemaCacheWithOptions
-  invalidateCachedRemoteSchema = lift . invalidateCachedRemoteSchema
+  buildSchemaCacheWithOptions a b = lift $ buildSchemaCacheWithOptions a b
 
 buildSchemaCache :: (CacheRWM m) => m ()
-buildSchemaCache = buildSchemaCacheWithOptions CatalogUpdate
+buildSchemaCache = buildSchemaCacheWithOptions CatalogUpdate mempty
 
 -- | Rebuilds the schema cache. If an object with the given object id became newly inconsistent,
 -- raises an error about it specifically. Otherwise, raises a generic metadata inconsistency error.

server/src-lib/Hasura/Server/App.hs

@@ -5,6 +5,7 @@ module Hasura.Server.App where
 
 import           Control.Concurrent.MVar
 import           Control.Exception                      (IOException, try)
+import           Control.Lens                           (view, _2)
 import           Control.Monad.Stateless
 import           Data.Aeson                             hiding (json)
 import           Data.Either                            (isRight)
@@ -461,9 +462,9 @@ mkWaiApp isoLevel logger sqlGenCtx enableAL pool ci httpManager mode corsCfg ena
     (cacheRef, cacheBuiltTime) <- do
       pgResp <- runExceptT $ peelRun runCtx pgExecCtxSer Q.ReadWrite $
         (,) <$> buildRebuildableSchemaCache <*> liftTx fetchLastUpdate
-      (schemaCache, time) <- liftIO $ either initErrExit return pgResp
+      (schemaCache, event) <- liftIO $ either initErrExit return pgResp
       scRef <- liftIO $ newIORef (schemaCache, initSchemaCacheVer)
-      return (scRef, snd <$> time)
+      return (scRef, view _2 <$> event)
 
     cacheLock <- liftIO $ newMVar ()
     planCache <- liftIO $ E.initPlanCache planCacheOptions

server/src-lib/Hasura/Server/Migrate.hs

@@ -16,9 +16,6 @@ module Hasura.Server.Migrate
   , dropCatalog
   ) where
 
-import           Control.Monad.Unique
-import           Data.Time.Clock               (UTCTime)
-
 import           Hasura.Prelude
 
 import qualified Data.Aeson                    as A
@@ -29,6 +26,10 @@ import qualified Database.PG.Query.Connection  as Q
 import qualified Language.Haskell.TH.Lib       as TH
 import qualified Language.Haskell.TH.Syntax    as TH
 
+import           Control.Lens                  (view, _2)
+import           Control.Monad.Unique
+import           Data.Time.Clock               (UTCTime)
+
 import           Hasura.Logging                (Hasura, LogLevel (..), ToEngineLog (..))
 import           Hasura.RQL.DDL.Relationship
 import           Hasura.RQL.DDL.Schema
@@ -163,7 +164,7 @@ migrateCatalog migrationTime = do
     buildCacheAndRecreateSystemMetadata :: m (RebuildableSchemaCache m)
     buildCacheAndRecreateSystemMetadata = do
       schemaCache <- buildRebuildableSchemaCache
-      snd <$> runCacheRWT schemaCache recreateSystemMetadata
+      view _2 <$> runCacheRWT schemaCache recreateSystemMetadata
 
     -- the old 0.8 catalog version is non-integral, so we store it in the database as a string
     getCatalogVersion = liftTx $ runIdentity . Q.getRow <$> Q.withQE defaultTxErrorHandler

server/src-lib/Hasura/Server/Migrate/Version.hs

@@ -12,7 +12,7 @@ import           Hasura.Prelude
 import qualified Data.Text      as T
 
 latestCatalogVersion :: Integer
-latestCatalogVersion = 30
+latestCatalogVersion = 31
 
 latestCatalogVersionString :: T.Text
 latestCatalogVersionString = T.pack $ show latestCatalogVersion

server/src-lib/Hasura/Server/Query.hs

@@ -150,23 +150,21 @@ $(deriveJSON
   ''RQLQueryV2
  )
 
-fetchLastUpdate :: Q.TxE QErr (Maybe (InstanceId, UTCTime))
-fetchLastUpdate = do
-  Q.withQE defaultTxErrorHandler
-    [Q.sql|
-       SELECT instance_id::text, occurred_at
+fetchLastUpdate :: Q.TxE QErr (Maybe (InstanceId, UTCTime, CacheInvalidations))
+fetchLastUpdate = over (_Just._3) Q.getAltJ <$> Q.withQE defaultTxErrorHandler [Q.sql|
+  SELECT instance_id::text, occurred_at, invalidations
   FROM hdb_catalog.hdb_schema_update_event
   ORDER BY occurred_at DESC LIMIT 1
   |] () True
 
-recordSchemaUpdate :: InstanceId -> Q.TxE QErr ()
-recordSchemaUpdate instanceId =
+recordSchemaUpdate :: InstanceId -> CacheInvalidations -> Q.TxE QErr ()
+recordSchemaUpdate instanceId invalidations =
   liftTx $ Q.unitQE defaultTxErrorHandler [Q.sql|
              INSERT INTO hdb_catalog.hdb_schema_update_event
-               (instance_id, occurred_at) VALUES ($1::uuid, DEFAULT)
+               (instance_id, occurred_at, invalidations) VALUES ($1::uuid, DEFAULT, $2::json)
              ON CONFLICT ((occurred_at IS NOT NULL))
-             DO UPDATE SET instance_id = $1::uuid, occurred_at = DEFAULT
-            |] (Identity instanceId) True
+             DO UPDATE SET instance_id = $1::uuid, occurred_at = DEFAULT, invalidations = $2::json
+            |] (instanceId, Q.AltJ invalidations) True
 
 runQuery
   :: (HasVersion, MonadIO m, MonadError QErr m)
@@ -184,12 +182,12 @@ runQuery pgExecCtx instanceId userInfo sc hMgr sqlGenCtx systemDefined query = d
   either throwError withReload resE
   where
     runCtx = RunCtx userInfo hMgr sqlGenCtx
-    withReload r = do
+    withReload (result, updatedCache, invalidations) = do
       when (queryModifiesSchemaCache query) $ do
-        e <- liftIO $ runExceptT $ runLazyTx pgExecCtx Q.ReadWrite
-             $ liftTx $ recordSchemaUpdate instanceId
+        e <- liftIO $ runExceptT $ runLazyTx pgExecCtx Q.ReadWrite $ liftTx $
+          recordSchemaUpdate instanceId invalidations
         liftEither e
-      return r
+      return (result, updatedCache)
 
 -- | A predicate that determines whether the given query might modify/rebuild the schema cache. If
 -- so, it needs to acquire the global lock on the schema cache so that other queries do not modify

server/src-lib/Hasura/Server/SchemaUpdate.hs

@@ -60,7 +60,8 @@ data EventPayload
   = EventPayload
   { _epInstanceId    :: !InstanceId
   , _epOccurredAt    :: !UTC.UTCTime
-  } deriving (Show, Eq)
+  , _epInvalidations :: !CacheInvalidations
+  }
 $(deriveJSON (aesonDrop 3 snakeCase) ''EventPayload)
 
 data ThreadError
@@ -136,9 +137,9 @@ listener sqlGenCtx pool logger httpMgr updateEventRef
         Just time -> (dbInstId /= instanceId) && accrdAt > time
 
     refreshCache Nothing = return ()
-    refreshCache (Just (dbInstId, accrdAt)) =
+    refreshCache (Just (dbInstId, accrdAt, invalidations)) =
       when (shouldRefresh dbInstId accrdAt) $
-        refreshSchemaCache sqlGenCtx pool logger httpMgr cacheRef
+        refreshSchemaCache sqlGenCtx pool logger httpMgr cacheRef invalidations
           threadType "schema cache reloaded after postgres listen init"
 
     notifyHandler = \case
@@ -179,7 +180,7 @@ processor sqlGenCtx pool logger httpMgr updateEventRef
     event <- STM.atomically getLatestEvent
     logInfo logger threadType $ object ["processed_event" .= event]
     when (shouldReload event) $
-      refreshSchemaCache sqlGenCtx pool logger httpMgr cacheRef
+      refreshSchemaCache sqlGenCtx pool logger httpMgr cacheRef (_epInvalidations event)
         threadType "schema cache reloaded"
   where
     -- checks if there is an event
@@ -202,15 +203,17 @@ refreshSchemaCache
   -> Logger Hasura
   -> HTTP.Manager
   -> SchemaCacheRef
+  -> CacheInvalidations
   -> ThreadType
   -> T.Text -> IO ()
-refreshSchemaCache sqlGenCtx pool logger httpManager cacheRef threadType msg = do
+refreshSchemaCache sqlGenCtx pool logger httpManager cacheRef invalidations threadType msg = do
   -- Reload schema cache from catalog
   resE <- liftIO $ runExceptT $ withSCUpdate cacheRef logger do
     rebuildableCache <- fst <$> liftIO (readIORef $ _scrCache cacheRef)
-    buildSchemaCacheWithOptions CatalogSync
+    ((), cache, _) <- buildSchemaCacheWithOptions CatalogSync invalidations
       & runCacheRWT rebuildableCache
       & peelRun runCtx pgCtx PG.ReadWrite
+    pure ((), cache)
   case resE of
     Left e   -> logError logger threadType $ TEQueryError e
     Right () -> logInfo logger threadType $ object ["message" .= msg]

server/src-rsr/initialise.sql

@@ -411,7 +411,8 @@ CREATE TABLE hdb_catalog.remote_schemas (
 
 CREATE TABLE hdb_catalog.hdb_schema_update_event (
   instance_id uuid NOT NULL,
-  occurred_at timestamptz NOT NULL DEFAULT NOW()
+  occurred_at timestamptz NOT NULL DEFAULT NOW(),
+  invalidations json NOT NULL
 );
 
 CREATE UNIQUE INDEX hdb_schema_update_event_one_row
@@ -422,13 +423,16 @@ $function$
   DECLARE
     instance_id uuid;
     occurred_at timestamptz;
+    invalidations json;
     curr_rec record;
   BEGIN
     instance_id = NEW.instance_id;
     occurred_at = NEW.occurred_at;
+    invalidations = NEW.invalidations;
     PERFORM pg_notify('hasura_schema_update', json_build_object(
       'instance_id', instance_id,
-      'occurred_at', occurred_at
+      'occurred_at', occurred_at,
+      'invalidations', invalidations
       )::text);
     RETURN curr_rec;
   END;

server/src-rsr/migrations/30_to_31.sql

@@ -0,0 +1,22 @@
+TRUNCATE hdb_catalog.hdb_schema_update_event;
+ALTER TABLE hdb_catalog.hdb_schema_update_event ADD COLUMN invalidations json NOT NULL;
+CREATE OR REPLACE FUNCTION hdb_catalog.hdb_schema_update_event_notifier() RETURNS trigger AS
+$function$
+  DECLARE
+    instance_id uuid;
+    occurred_at timestamptz;
+    invalidations json;
+    curr_rec record;
+  BEGIN
+    instance_id = NEW.instance_id;
+    occurred_at = NEW.occurred_at;
+    invalidations = NEW.invalidations;
+    PERFORM pg_notify('hasura_schema_update', json_build_object(
+      'instance_id', instance_id,
+      'occurred_at', occurred_at,
+      'invalidations', invalidations
+      )::text);
+    RETURN curr_rec;
+  END;
+$function$
+LANGUAGE plpgsql;

server/src-rsr/migrations/31_to_30.sql

@@ -0,0 +1,19 @@
+TRUNCATE hdb_catalog.hdb_schema_update_event;
+CREATE OR REPLACE FUNCTION hdb_catalog.hdb_schema_update_event_notifier() RETURNS trigger AS
+$function$
+  DECLARE
+    instance_id uuid;
+    occurred_at timestamptz;
+    curr_rec record;
+  BEGIN
+    instance_id = NEW.instance_id;
+    occurred_at = NEW.occurred_at;
+    PERFORM pg_notify('hasura_schema_update', json_build_object(
+      'instance_id', instance_id,
+      'occurred_at', occurred_at
+      )::text);
+    RETURN curr_rec;
+  END;
+$function$
+LANGUAGE plpgsql;
+ALTER TABLE hdb_catalog.hdb_schema_update_event DROP COLUMN invalidations;

server/src-test/Hasura/Server/MigrateSpec.hs

@@ -36,11 +36,10 @@ instance (MonadBase IO m) => TableCoreInfoRM (CacheRefT m)
 instance (MonadBase IO m) => CacheRM (CacheRefT m) where
   askSchemaCache = CacheRefT (fmap lastBuiltSchemaCache . readMVar)
 
-instance (MonadIO m, MonadBaseControl IO m, MonadTx m, MonadUnique m) => CacheRWM (CacheRefT m) where
-  buildSchemaCacheWithOptions options = CacheRefT $ flip modifyMVar \schemaCache ->
-    swap <$> runCacheRWT schemaCache (buildSchemaCacheWithOptions options)
-  invalidateCachedRemoteSchema name = CacheRefT $ flip modifyMVar \schemaCache ->
-    swap <$> runCacheRWT schemaCache (invalidateCachedRemoteSchema name)
+instance (MonadIO m, MonadBaseControl IO m, MonadTx m) => CacheRWM (CacheRefT m) where
+  buildSchemaCacheWithOptions reason invalidations = CacheRefT $ flip modifyMVar \schemaCache -> do
+    ((), cache, _) <- runCacheRWT schemaCache (buildSchemaCacheWithOptions reason invalidations)
+    pure (cache, ())
 
 instance Example (CacheRefT m ()) where
   type Arg (CacheRefT m ()) = CacheRefT m :~> IO

server/tests-py/queries/v1/set_table_is_enum/relationship_with_inconsistent_enum_table.yaml

@@ -0,0 +1,55 @@
+# This is a regression test for #3791.
+- description: Setup enum table, create relationship, and insert invalid enum value
+  url: /v1/query
+  status: 200
+  query:
+    type: bulk
+    args:
+    - type: set_table_is_enum
+      args:
+        table: weekdays
+        is_enum: true
+    - type: create_object_relationship
+      args:
+        table: employees
+        name: favorite_color_object
+        using:
+          foreign_key_constraint_on: favorite_color
+    - type: run_sql
+      args:
+        sql: INSERT INTO colors (value, comment) VALUES ('illegal+graphql+identifier', '')
+    - type: reload_metadata
+      args: {}
+
+- description: Query inconsistent objects
+  url: /v1/query
+  status: 200
+  response:
+    is_consistent: false
+    inconsistent_objects:
+    - definition:
+        schema: public
+        name: colors
+      reason: the table "colors" cannot be used as an enum because the value
+        "illegal+graphql+identifier" is not a valid GraphQL enum value name
+      type: table
+    - definition:
+        using:
+          foreign_key_constraint_on: favorite_color
+        name: favorite_color_object
+        comment:
+        table:
+          schema: public
+          name: employees
+      reason: table "colors" is not tracked
+      type: object_relation
+  query:
+    type: get_inconsistent_metadata
+    args: {}
+
+- description: Drop inconsistent objects
+  url: /v1/query
+  status: 200
+  query:
+    type: drop_inconsistent_metadata
+    args: {}

server/tests-py/test_v1_queries.py

@@ -679,6 +679,9 @@ class TestSetTableIsEnum(DefaultTestQueries):
     def test_add_test_schema_enum_table(self, hge_ctx):
         check_query_f(hge_ctx, self.dir() + '/add_test_schema_enum_table.yaml')
 
+    def test_relationship_with_inconsistent_enum_table(self, hge_ctx):
+        check_query_f(hge_ctx, self.dir() + '/relationship_with_inconsistent_enum_table.yaml')
+
 class TestSetTableCustomFields(DefaultTestQueries):
     @classmethod
     def dir(cls):
@@ -735,5 +738,3 @@ class TestBulkQuery(DefaultTestQueries):
 
     def test_run_bulk_with_select_and_reads(self, hge_ctx):
         check_query_f(hge_ctx, self.dir() + '/select_with_reads.yaml')
-
-