server: drop LazyTxT newtype

This is a follow-up to #1959. Today, I spent a while in review figuring out that a harmless PR change didn't do anything, because it was moving from a `runLazy...` to something without the `Lazy`. So let's get that source of confusion removed. This should be a bit easier to review commit by commit, since some of the functions had confusing names. (E.g. there was a misnamed `Migrate.Internal.runTx` before.) The change should be a no-op. https://github.com/hasura/graphql-engine-mono/pull/2335 GitOrigin-RevId: 0f284c4c0f814482d7827e7732a6d49e7735b302
2024-12-15 09:22:43 +03:00 · 2021-09-15 22:45:49 +02:00 · 2021-09-15 22:45:49 +02:00 · fe035125f4
commit fe035125f4
parent 9b7234b861
25 changed files with 103 additions and 154 deletions
--- a/server/src-lib/Hasura/App.hs
+++ b/server/src-lib/Hasura/App.hs
@ -745,7 +745,7 @@ runHGEServer setupHook env ServeOptions{..} ServeCtx{..} initTime postPollHook s
      -- event triggers should be tied to the life cycle of a source
      forM_ pgSources $ \pgSource -> do
        logger $ mkGenericStrLog LevelInfo "event_triggers" "unlocking events that are locked by the HGE"
-        let unlockEvents' l = MetadataStorageT $ runLazyTx (_pscExecCtx pgSource) Q.ReadWrite $ liftTx $ unlockEvents l
+        let unlockEvents' l = MetadataStorageT $ runTx (_pscExecCtx pgSource) Q.ReadWrite $ liftTx $ unlockEvents l
        unlockEventsForShutdown hasuraLogger "event_triggers" "" unlockEvents' leEvents

    shutdownAsyncActions
--- a/server/src-lib/Hasura/Backends/Postgres/Connection.hs
+++ b/server/src-lib/Hasura/Backends/Postgres/Connection.hs
@ -5,11 +5,10 @@

 module Hasura.Backends.Postgres.Connection
  ( MonadTx(..)
-  , LazyTxT(..)

-  , runLazyTx
+  , runTx
+  , runTxWithCtx
  , runQueryTx
-  , runQueryTxWithCtx
  , withUserInfo
  , withTraceContext
  , setHeadersTx
@ -98,56 +97,51 @@ instance (MonadTx m) => MonadTx (Tracing.TraceT m) where
 instance (MonadIO m) => MonadTx (Q.TxET QErr m) where
  liftTx = hoist liftIO

-- | This type *used to be* like 'Q.TxE', but deferred acquiring a Postgres
-- connection until the first execution of 'liftTx'.  If no call to 'liftTx' is
-- ever reached (i.e. a successful result is returned or an error is raised
-- before ever executing a query), no connection was ever acquired.
--
-- This was useful for certain code paths that only conditionally need database
-- access. For example, although most queries will eventually hit Postgres,
-- introspection queries or queries that exclusively use remote schemas never
-- will; using 'LazyTxT e m' keeps those branches from unnecessarily allocating
-- a connection.
--
-- However introspection queries and remote queries now never end up producing a
-- 'LazyTxT' action, and hence the laziness adds no benefit, so that we could
-- simplify this type, its name being a mere reminder of a past design of
-- graphql-engine.
--
-- It may be worthwhile in the future to simply replace this type with Q.TxET
-- entirely.
-newtype LazyTxT e m a = LazyTxT {unLazyTxT :: Q.TxET e m a}
-  deriving (Functor, Applicative, Monad, MonadError e, MonadIO, MonadTrans)
-
-runLazyTx
+-- | Executes the given query in a transaction of the specified
+-- mode, within the provided PGExecCtx.
+runTx
  :: ( MonadIO m
     , MonadBaseControl IO m
     )
  => PGExecCtx
  -> Q.TxAccess
-  -> LazyTxT QErr m a -> ExceptT QErr m a
-runLazyTx pgExecCtx = \case
-  Q.ReadOnly  -> _pecRunReadOnly pgExecCtx . unLazyTxT
-  Q.ReadWrite -> _pecRunReadWrite pgExecCtx . unLazyTxT
+  -> Q.TxET QErr m a
+  -> ExceptT QErr m a
+runTx pgExecCtx = \case
+  Q.ReadOnly  -> _pecRunReadOnly pgExecCtx
+  Q.ReadWrite -> _pecRunReadWrite pgExecCtx
+
+runTxWithCtx
+  :: ( MonadIO m
+     , MonadBaseControl IO m
+     , MonadError QErr m
+     , Tracing.MonadTrace m
+     , UserInfoM m
+     )
+  => PGExecCtx
+  -> Q.TxAccess
+  -> Q.TxET QErr m a
+  -> m a
+runTxWithCtx pgExecCtx txAccess tx = do
+  traceCtx <- Tracing.currentContext
+  userInfo <- askUserInfo
+  liftEitherM
+    $ runExceptT
+    $ runTx pgExecCtx txAccess
+    $ withTraceContext traceCtx
+    $ withUserInfo userInfo tx

 -- | This runs the given set of statements (Tx) without wrapping them in BEGIN
 -- and COMMIT. This should only be used for running a single statement query!
 runQueryTx
-  :: (MonadIO m, MonadError QErr m) => PGExecCtx -> LazyTxT QErr IO a -> m a
-runQueryTx pgExecCtx ltx =
-  liftEither =<< liftIO (runExceptT $ _pecRunReadNoTx pgExecCtx (unLazyTxT ltx))
-
-- NOTE: Same warning as 'runQueryTx' applies here.
-- This variant of 'runQueryTx' allows passing the `userInfo` context and `tracecontext`.
-runQueryTxWithCtx
-  :: (MonadIO m, MonadError QErr m)
-  => UserInfo
-  -> Tracing.TraceContext
-  -> PGExecCtx
-  -> LazyTxT QErr IO a
+  :: ( MonadIO m
+     , MonadError QErr m
+     )
+  => PGExecCtx
+  -> Q.TxET QErr IO a
  -> m a
-runQueryTxWithCtx userInfo traceCtx pgExecCtx =
-  runQueryTx pgExecCtx . withUserInfo userInfo . withTraceContext traceCtx
+runQueryTx pgExecCtx tx =
+  liftEither =<< liftIO (runExceptT $ _pecRunReadNoTx pgExecCtx tx)

 setHeadersTx :: (MonadIO m) => SessionVariables -> Q.TxET QErr m ()
 setHeadersTx session = do
@ -159,8 +153,8 @@ setHeadersTx session = do
 sessionInfoJsonExp :: SessionVariables -> S.SQLExp
 sessionInfoJsonExp = S.SELit . encodeToStrictText

-withUserInfo :: (MonadIO m) => UserInfo -> LazyTxT QErr m a -> LazyTxT QErr m a
-withUserInfo uInfo ltx = LazyTxT (setHeadersTx $ _uiSession uInfo) >> ltx
+withUserInfo :: (MonadIO m) => UserInfo -> Q.TxET QErr m a -> Q.TxET QErr m a
+withUserInfo uInfo tx = setHeadersTx (_uiSession uInfo) >> tx

 setTraceContextInTx :: (MonadIO m) => Tracing.TraceContext -> Q.TxET QErr m ()
 setTraceContextInTx traceCtx = Q.unitQE defaultTxErrorHandler sql () False
@ -173,20 +167,13 @@ setTraceContextInTx traceCtx = Q.unitQE defaultTxErrorHandler sql () False
 withTraceContext
  :: (MonadIO m)
  => Tracing.TraceContext
-  -> LazyTxT QErr m a
-  -> LazyTxT QErr m a
-withTraceContext ctx ltx = LazyTxT (setTraceContextInTx ctx) >> ltx
+  -> Q.TxET QErr m a
+  -> Q.TxET QErr m a
+withTraceContext ctx tx = setTraceContextInTx ctx >> tx

 deriving instance Tracing.MonadTrace m => Tracing.MonadTrace (Q.TxET e m)
-deriving instance Tracing.MonadTrace m => Tracing.MonadTrace (LazyTxT e m)

-deriving instance (MonadIO m) => MonadTx (LazyTxT QErr m)
-
-deriving instance (MonadBase IO m) => MonadBase IO (LazyTxT e m)
-
-deriving instance (MonadBaseControl IO m) => MonadBaseControl IO (LazyTxT e m)
-
-instance (MonadIO m) => MonadUnique (LazyTxT e m) where
+instance (MonadIO m) => MonadUnique (Q.TxET e m) where
  newUnique = liftIO newUnique

 doesSchemaExist :: MonadTx m => SchemaName -> m Bool
--- a/server/src-lib/Hasura/Backends/Postgres/DDL/RunSQL.hs
+++ b/server/src-lib/Hasura/Backends/Postgres/DDL/RunSQL.hs
@ -31,7 +31,6 @@ import           Hasura.RQL.DDL.Schema.Common
 import           Hasura.RQL.DDL.Schema.Diff
 import           Hasura.RQL.Types                          hiding (ConstraintName, fmFunction,
                                                            tmComputedFields, tmTable)
-import           Hasura.RQL.Types.Run
 import           Hasura.Server.Utils                       (quoteRegex)
 import           Hasura.Session

@ -161,7 +160,7 @@ runRunSQL q@RunSQL{..} = do
        $ withUserInfo userInfo
        $ execRawSQL rSql
    else do
-      runQueryLazyTx pgExecCtx rTxAccessMode $ execRawSQL rSql
+      runTxWithCtx pgExecCtx rTxAccessMode $ execRawSQL rSql
  where
    execRawSQL :: (MonadTx n) => Text -> n EncJSON
    execRawSQL =
@ -185,12 +184,12 @@ withMetadataCheck
     , MonadError QErr m
     , MonadIO m
     )
-  => SourceName -> Bool -> Q.TxAccess -> LazyTxT QErr m a -> m a
+  => SourceName -> Bool -> Q.TxAccess -> Q.TxET QErr m a -> m a
 withMetadataCheck source cascade txAccess action = do
  SourceInfo _ preActionTables preActionFunctions sourceConfig <- askSourceInfo @('Postgres pgKind) source

  (actionResult, metadataUpdater) <-
-    liftEitherM $ runExceptT $ runLazyTx (_pscExecCtx sourceConfig) txAccess $ do
+    liftEitherM $ runExceptT $ runTx (_pscExecCtx sourceConfig) txAccess $ do
      -- Drop event triggers so no interference is caused to the sql query
      forM_ (M.elems preActionTables) $ \tableInfo -> do
        let eventTriggers = _tiEventTriggerInfoMap tableInfo
--- a/server/src-lib/Hasura/Backends/Postgres/DDL/Source.hs
+++ b/server/src-lib/Hasura/Backends/Postgres/DDL/Source.hs
@ -64,7 +64,7 @@ resolveDatabaseMetadata
   . (Backend ('Postgres pgKind), ToMetadataFetchQuery pgKind, MonadIO m, MonadBaseControl IO m)
  => SourceConfig ('Postgres pgKind) -> m (Either QErr (ResolvedSource ('Postgres pgKind)))
 resolveDatabaseMetadata sourceConfig = runExceptT do
-  (tablesMeta, functionsMeta, pgScalars) <- runLazyTx (_pscExecCtx sourceConfig) Q.ReadOnly $ do
+  (tablesMeta, functionsMeta, pgScalars) <- runTx (_pscExecCtx sourceConfig) Q.ReadOnly $ do
    tablesMeta    <- fetchTableMetadata
    functionsMeta <- fetchFunctionMetadata
    pgScalars     <- fetchPgScalars
@ -126,7 +126,7 @@ initCatalogForSource maintenanceMode migrationTime = do
      case NE.nonEmpty neededMigrations of
        Just nonEmptyNeededMigrations -> do
          -- Migrations aren't empty. We need to update the catalog version after migrations
-          traverse_ snd nonEmptyNeededMigrations
+          liftTx $ traverse_ snd nonEmptyNeededMigrations
          setCatalogVersion "43" migrationTime
        Nothing ->
          -- No migrations exists, implies the database is migrated to latest metadata catalog version
@ -161,18 +161,18 @@ migrateSourceCatalogFrom prevVersion
        <> latestSourceCatalogVersionText
        <> ", but the current version is " <> prevVersion
  | otherwise = do
-      traverse_ snd neededMigrations
+      liftTx $ traverse_ snd neededMigrations
      setSourceCatalogVersion
  where
    neededMigrations =
      dropWhile ((/= prevVersion) . fst) sourceMigrations

-sourceMigrations :: (MonadTx m) => [(Text, m ())]
+sourceMigrations :: [(Text, Q.TxE QErr ())]
 sourceMigrations =
  $(let migrationFromFile from =
          let to = from + 1
              path = "src-rsr/pg_source_migrations/" <> show from <> "_to_" <> show to <> ".sql"
-          in [| runTx $(makeRelativeToProject path >>= Q.sqlFromFile) |]
+          in [| Q.multiQE defaultTxErrorHandler $(makeRelativeToProject path >>= Q.sqlFromFile) |]

        migrationsFromFile = map $ \(from :: Integer) ->
          [| ($(TH.lift $ tshow from), $(migrationFromFile from)) |]
@ -181,11 +181,11 @@ sourceMigrations =
   )

 -- Upgrade the hdb_catalog schema to v43 (Metadata catalog)
-upMigrationsUntil43 :: MonadTx m => [(Text, m ())]
+upMigrationsUntil43 :: [(Text, Q.TxE QErr ())]
 upMigrationsUntil43 =
    $(let migrationFromFile from to =
            let path = "src-rsr/migrations/" <> from <> "_to_" <> to <> ".sql"
-             in [| runTx $(makeRelativeToProject path >>= Q.sqlFromFile) |]
+             in [| Q.multiQE defaultTxErrorHandler $(makeRelativeToProject path >>= Q.sqlFromFile) |]

          migrationsFromFile = map $ \(to :: Integer) ->
            let from = to - 1
--- a/server/src-lib/Hasura/Backends/Postgres/Instances/Execute.hs
+++ b/server/src-lib/Hasura/Backends/Postgres/Instances/Execute.hs
@ -55,7 +55,7 @@ instance

  type PreparedQuery    ('Postgres pgKind) = PreparedSql
  type MultiplexedQuery ('Postgres pgKind) = PGL.MultiplexedQuery
-  type ExecutionMonad   ('Postgres pgKind) = Tracing.TraceT (LazyTxT QErr IO)
+  type ExecutionMonad   ('Postgres pgKind) = Tracing.TraceT (Q.TxET QErr IO)

  mkDBQueryPlan = pgDBQueryPlan
  mkDBMutationPlan = pgDBMutationPlan
@ -125,7 +125,7 @@ pgDBLiveQueryExplain plan = do
      -- query, maybe resulting in privilege escalation:
      explainQuery = Q.fromText $ "EXPLAIN (FORMAT TEXT) " <> queryText
  cohortId <- newCohortId
-  explanationLines <- liftEitherM $ runExceptT $ runLazyTx pgExecCtx Q.ReadOnly $
+  explanationLines <- liftEitherM $ runExceptT $ runTx pgExecCtx Q.ReadOnly $
                      map runIdentity <$> PGL.executeQuery explainQuery [(cohortId, _lqpVariables plan)]
  pure $ LiveQueryPlanExplanation queryText explanationLines $ _lqpVariables plan

@ -142,7 +142,7 @@ convertDelete
  -> IR.AnnDelG ('Postgres pgKind) (Const Void) (UnpreparedValue ('Postgres pgKind))
  -> Bool
  -> QueryTagsComment
-  -> m (Tracing.TraceT (LazyTxT QErr IO) EncJSON)
+  -> m (Tracing.TraceT (Q.TxET QErr IO) EncJSON)
 convertDelete userInfo deleteOperation stringifyNum queryTags = do
  preparedDelete <- traverse (prepareWithoutPlan userInfo) deleteOperation
  pure $ flip runReaderT queryTags $ PGE.execDeleteQuery stringifyNum userInfo (preparedDelete, Seq.empty)
@ -157,7 +157,7 @@ convertUpdate
  -> IR.AnnUpdG ('Postgres pgKind) (Const Void) (UnpreparedValue ('Postgres pgKind))
  -> Bool
  -> QueryTagsComment
-  -> m (Tracing.TraceT (LazyTxT QErr IO) EncJSON)
+  -> m (Tracing.TraceT (Q.TxET QErr IO) EncJSON)
 convertUpdate userInfo updateOperation stringifyNum queryTags = do
  preparedUpdate <- traverse (prepareWithoutPlan userInfo) updateOperation
  if null $ IR.uqp1OpExps updateOperation
@ -178,7 +178,7 @@ convertInsert
  -> IR.AnnInsert ('Postgres pgKind) (Const Void) (UnpreparedValue ('Postgres pgKind))
  -> Bool
  -> QueryTagsComment
-  -> m (Tracing.TraceT (LazyTxT QErr IO) EncJSON)
+  -> m (Tracing.TraceT (Q.TxET QErr IO) EncJSON)
 convertInsert userInfo insertOperation stringifyNum queryTags = do
  preparedInsert <- traverse (prepareWithoutPlan userInfo) insertOperation
  pure $ flip runReaderT queryTags $ convertToSQLTransaction preparedInsert userInfo Seq.empty stringifyNum
@ -197,7 +197,7 @@ convertFunction
  -- ^ VOLATILE function as 'SelectExp'
  -> QueryTagsComment
  -- ^ Query Tags
-  -> m (Tracing.TraceT (LazyTxT QErr IO) EncJSON)
+  -> m (Tracing.TraceT (Q.TxET QErr IO) EncJSON)
 convertFunction userInfo jsonAggSelect unpreparedQuery queryTags = do
  -- Transform the RQL AST into a prepared SQL query
  (preparedQuery, PlanningSt _ _ planVals )
@ -277,7 +277,7 @@ pgDBSubscriptionPlan userInfo _sourceName sourceConfig unpreparedAST queryTags =
 mkCurPlanTx
  :: UserInfo
  -> PreparedSql
-  -> (Tracing.TraceT (LazyTxT QErr IO) EncJSON, Maybe PreparedSql)
+  -> (Tracing.TraceT (Q.TxET QErr IO) EncJSON, Maybe PreparedSql)
 mkCurPlanTx userInfo ps@(PreparedSql q prepMap) =
  -- generate the SQL and prepared vars or the bytestring
  let args = withUserVars (_uiSession userInfo) prepMap
--- a/server/src-lib/Hasura/Backends/Postgres/Instances/Transport.hs
+++ b/server/src-lib/Hasura/Backends/Postgres/Instances/Transport.hs
@ -58,7 +58,7 @@ runPGQuery
  -> UserInfo
  -> L.Logger L.Hasura
  -> SourceConfig ('Postgres pgKind)
-  -> Tracing.TraceT (LazyTxT QErr IO) EncJSON
+  -> Tracing.TraceT (Q.TxET QErr IO) EncJSON
  -> Maybe EQ.PreparedSql
  -> m (DiffTime, EncJSON)
  -- ^ Also return the time spent in the PG query; for telemetry.
@ -80,7 +80,7 @@ runPGMutation
  -> UserInfo
  -> L.Logger L.Hasura
  -> SourceConfig ('Postgres pgKind)
-  -> Tracing.TraceT (LazyTxT QErr IO) EncJSON
+  -> Tracing.TraceT (Q.TxET QErr IO) EncJSON
  -> Maybe EQ.PreparedSql
  -> m (DiffTime, EncJSON)
  -- ^ Also return 'Mutation' when the operation was a mutation, and the time
@ -92,7 +92,7 @@ runPGMutation reqId query fieldName userInfo logger sourceConfig tx _genSql =  d
  withElapsedTime $ trace ("Postgres Mutation for root field " <>> fieldName) $
    Tracing.interpTraceT (
      liftEitherM . liftIO . runExceptT
-      . runLazyTx (_pscExecCtx sourceConfig) Q.ReadWrite
+      . runTx (_pscExecCtx sourceConfig) Q.ReadWrite
      . withTraceContext ctx
      . withUserInfo userInfo
      ) tx
@ -159,7 +159,7 @@ runPGMutationTransaction reqId query userInfo logger sourceConfig mutations = do
  withElapsedTime $ do
    Tracing.interpTraceT (
      liftEitherM . liftIO . runExceptT
-      . runLazyTx (_pscExecCtx sourceConfig) Q.ReadWrite
+      . runTx (_pscExecCtx sourceConfig) Q.ReadWrite
      . withTraceContext ctx
      . withUserInfo userInfo
      ) $ flip OMap.traverseWithKey mutations \fieldName dbsi ->
--- a/server/src-lib/Hasura/GraphQL/Execute/Action.hs
+++ b/server/src-lib/Hasura/GraphQL/Execute/Action.hs
@ -102,7 +102,7 @@ runActionExecution userInfo aep =
          let selectAST = f actionLogResponse
          selectResolved <- traverse (prepareWithoutPlan userInfo) selectAST
          let querySQL = Q.fromBuilder $ toSQL $ RS.mkSQLSelect jsonAggSelect selectResolved
-          liftEitherM $ runExceptT $ runLazyTx (_pscExecCtx srcConfig) Q.ReadOnly $ liftTx $ asSingleRowJsonResp querySQL []
+          liftEitherM $ runExceptT $ runTx (_pscExecCtx srcConfig) Q.ReadOnly $ liftTx $ asSingleRowJsonResp querySQL []
    AEPAsyncMutation actionId -> pure $ (,Nothing) $ encJFromJValue $ actionIdToText actionId

 -- | Synchronously execute webhook handler and resolve response to action "output"
@ -140,7 +140,7 @@ resolveActionExecution env logger userInfo annAction execContext =
                      => SourceConfig ('Postgres 'Vanilla) -> RS.AnnSimpleSelect ('Postgres 'Vanilla) -> [Q.PrepArg] -> m EncJSON
    executeActionInDb sourceConfig astResolved prepArgs = do
      let jsonAggType = mkJsonAggSelect outputType
-      liftEitherM $ runExceptT $ runLazyTx (_pscExecCtx sourceConfig) Q.ReadOnly $
+      liftEitherM $ runExceptT $ runTx (_pscExecCtx sourceConfig) Q.ReadOnly $
        liftTx $ asSingleRowJsonResp (Q.fromBuilder $ toSQL $ RS.mkSQLSelect jsonAggType astResolved) prepArgs

    runWebhook :: (HasVersion, MonadIO m, MonadError QErr m, Tracing.MonadTrace m)
--- a/server/src-lib/Hasura/GraphQL/Execute/Backend.hs
+++ b/server/src-lib/Hasura/GraphQL/Execute/Backend.hs
@ -37,7 +37,7 @@ import           Hasura.Session
 import           Hasura.Metadata.Class
 import           Hasura.Tracing                          (TraceT)

-import           Hasura.Backends.Postgres.Connection     (LazyTxT)
+import qualified Database.PG.Query                       as Q
 import           Hasura.RQL.DDL.Schema.Cache             (CacheRWT)
 import           Hasura.RQL.Types.Run                    (RunT (..))
 import           Hasura.RQL.Types.SchemaCache.Build      (MetadataT (..))
@ -181,8 +181,8 @@ instance (MonadQueryTags m) => MonadQueryTags (TraceT m) where
 instance (MonadQueryTags m) => MonadQueryTags (MetadataStorageT m) where
  createQueryTags qtSourceConfig attr = retag (createQueryTags @m qtSourceConfig attr) :: Tagged (MetadataStorageT m) Text

-instance (MonadQueryTags m) => MonadQueryTags (LazyTxT QErr m) where
-  createQueryTags qtSourceConfig attr = retag (createQueryTags @m qtSourceConfig attr) :: Tagged (LazyTxT QErr m) Text
+instance (MonadQueryTags m) => MonadQueryTags (Q.TxET QErr m) where
+  createQueryTags qtSourceConfig attr = retag (createQueryTags @m qtSourceConfig attr) :: Tagged (Q.TxET QErr m) Text

 instance (MonadQueryTags m) => MonadQueryTags (MetadataT m) where
  createQueryTags qtSourceConfig attr = retag (createQueryTags @m qtSourceConfig attr) :: Tagged (MetadataT m) Text
--- a/server/src-lib/Hasura/Metadata/Class.hs
+++ b/server/src-lib/Hasura/Metadata/Class.hs
@ -20,6 +20,7 @@ import           Network.HTTP.Client.Extended

 import qualified Hasura.Tracing                         as Tracing

+import qualified Database.PG.Query                      as Q
 import           Hasura.Base.Error
 import           Hasura.Eventing.HTTP
 import           Hasura.Eventing.ScheduledTrigger.Types
@ -301,7 +302,7 @@ instance (MonadMetadataStorage m) => MonadMetadataStorage (MetadataT m) where
  clearActionData                      = lift . clearActionData
  setProcessingActionLogsToPending     = lift . setProcessingActionLogsToPending

-instance (MonadMetadataStorage m) => MonadMetadataStorage (LazyTxT QErr m) where
+instance (MonadMetadataStorage m) => MonadMetadataStorage (Q.TxET QErr m) where
  fetchMetadataResourceVersion         = lift fetchMetadataResourceVersion
  fetchMetadata                        = lift fetchMetadata
  fetchMetadataNotifications a b       = lift $ fetchMetadataNotifications a b
@ -491,4 +492,4 @@ instance (MonadMetadataStorageQueryAPI m) => MonadMetadataStorageQueryAPI (Reade
 instance (MonadMetadataStorageQueryAPI m) => MonadMetadataStorageQueryAPI (StateT s m)
 instance (MonadMetadataStorageQueryAPI m) => MonadMetadataStorageQueryAPI (Tracing.TraceT m)
 instance (MonadMetadataStorageQueryAPI m) => MonadMetadataStorageQueryAPI (MetadataT m)
-instance (MonadMetadataStorageQueryAPI m) => MonadMetadataStorageQueryAPI (LazyTxT QErr m)
+instance (MonadMetadataStorageQueryAPI m) => MonadMetadataStorageQueryAPI (Q.TxET QErr m)
--- a/server/src-lib/Hasura/RQL/DDL/Schema/Cache.hs
+++ b/server/src-lib/Hasura/RQL/DDL/Schema/Cache.hs
@ -368,7 +368,7 @@ buildSchemaCacheRule env = proc (metadata, invalidationKeys) -> do
              maintenanceMode <- _sccMaintenanceMode <$> askServerConfigCtx
              let
                  initCatalogAction =
-                    runExceptT $ runLazyTx (_pscExecCtx sc) Q.ReadWrite (initCatalogForSource maintenanceMode migrationTime)
+                    runExceptT $ runTx (_pscExecCtx sc) Q.ReadWrite (initCatalogForSource maintenanceMode migrationTime)
              -- The `initCatalogForSource` action is retried here because
              -- in cloud there will be multiple workers (graphql-engine instances)
              -- trying to migrate the source catalog, when needed. This introduces
--- a/server/src-lib/Hasura/RQL/DML/Count.hs
+++ b/server/src-lib/Hasura/RQL/DML/Count.hs
@ -26,7 +26,6 @@ import           Hasura.RQL.DML.Internal
 import           Hasura.RQL.DML.Types
 import           Hasura.RQL.IR.BoolExp
 import           Hasura.RQL.Types
-import           Hasura.RQL.Types.Run
 import           Hasura.SQL.Types
 import           Hasura.Session

@ -137,4 +136,4 @@ runCount
  => CountQuery -> m EncJSON
 runCount q = do
  sourceConfig <- askSourceConfig @('Postgres 'Vanilla) (cqSource q)
-  validateCountQ q >>= runQueryLazyTx (_pscExecCtx sourceConfig) Q.ReadOnly . countQToTx
+  validateCountQ q >>= runTxWithCtx (_pscExecCtx sourceConfig) Q.ReadOnly . countQToTx
--- a/server/src-lib/Hasura/RQL/DML/Delete.hs
+++ b/server/src-lib/Hasura/RQL/DML/Delete.hs
@ -33,7 +33,6 @@ import           Hasura.RQL.DML.Internal
 import           Hasura.RQL.DML.Types
 import           Hasura.RQL.IR.Delete
 import           Hasura.RQL.Types
-import           Hasura.RQL.Types.Run
 import           Hasura.Session

 import           Hasura.GraphQL.Execute.Backend
@ -111,5 +110,5 @@ runDelete q = do
  userInfo <- askUserInfo
  let queryTags = QueryTagsComment $ Tagged.untag $ createQueryTags @m Nothing (encodeOptionalQueryTags Nothing)
  validateDeleteQ q
-    >>= runQueryLazyTx (_pscExecCtx sourceConfig) Q.ReadWrite
+    >>= runTxWithCtx (_pscExecCtx sourceConfig) Q.ReadWrite
        . flip runReaderT queryTags . execDeleteQuery strfyNum userInfo
--- a/server/src-lib/Hasura/RQL/DML/Insert.hs
+++ b/server/src-lib/Hasura/RQL/DML/Insert.hs
@ -29,7 +29,6 @@ import           Hasura.RQL.DML.Internal
 import           Hasura.RQL.DML.Types
 import           Hasura.RQL.IR.Insert
 import           Hasura.RQL.Types
-import           Hasura.RQL.Types.Run
 import           Hasura.Session

 import           Hasura.GraphQL.Execute.Backend
@ -222,7 +221,7 @@ runInsert q = do
  res <- convInsQ q
  strfyNum <- stringifyNum . _sccSQLGenCtx <$> askServerConfigCtx
  let queryTags = QueryTagsComment $ Tagged.untag $ createQueryTags @m Nothing (encodeOptionalQueryTags Nothing)
-  runQueryLazyTx (_pscExecCtx sourceConfig) Q.ReadWrite $
+  runTxWithCtx (_pscExecCtx sourceConfig) Q.ReadWrite $
    runReaderT (execInsertQuery strfyNum userInfo res) queryTags

 decodeInsObjs :: (UserInfoM m, QErrM m) => Value -> m [InsObj ('Postgres 'Vanilla)]
--- a/server/src-lib/Hasura/RQL/DML/Select.hs
+++ b/server/src-lib/Hasura/RQL/DML/Select.hs
@ -25,7 +25,6 @@ import           Hasura.RQL.DML.Types
 import           Hasura.RQL.IR.OrderBy
 import           Hasura.RQL.IR.Select
 import           Hasura.RQL.Types
-import           Hasura.RQL.Types.Run
 import           Hasura.SQL.Types
 import           Hasura.Session

@ -328,4 +327,4 @@ runSelect
  => SelectQuery -> m EncJSON
 runSelect q = do
  sourceConfig <- askSourceConfig @('Postgres 'Vanilla) (getSourceDMLQuery q)
-  phaseOne q >>= runQueryLazyTx (_pscExecCtx sourceConfig) Q.ReadOnly . phaseTwo
+  phaseOne q >>= runTxWithCtx (_pscExecCtx sourceConfig) Q.ReadOnly . phaseTwo
--- a/server/src-lib/Hasura/RQL/DML/Update.hs
+++ b/server/src-lib/Hasura/RQL/DML/Update.hs
@ -32,7 +32,6 @@ import           Hasura.RQL.DML.Types
 import           Hasura.RQL.IR.BoolExp
 import           Hasura.RQL.IR.Update
 import           Hasura.RQL.Types
-import           Hasura.RQL.Types.Run
 import           Hasura.SQL.Types
 import           Hasura.Session

@ -206,5 +205,5 @@ runUpdate q = do
  strfyNum <- stringifyNum . _sccSQLGenCtx <$> askServerConfigCtx
  let queryTags = QueryTagsComment $ Tagged.untag $ createQueryTags @m Nothing (encodeOptionalQueryTags Nothing)
  validateUpdateQuery q
-    >>= runQueryLazyTx (_pscExecCtx sourceConfig) Q.ReadWrite
+    >>= runTxWithCtx (_pscExecCtx sourceConfig) Q.ReadWrite
        . flip runReaderT queryTags . execUpdateQuery strfyNum userInfo
--- a/server/src-lib/Hasura/RQL/Types.hs
+++ b/server/src-lib/Hasura/RQL/Types.hs
@ -180,9 +180,6 @@ instance (HasServerConfigCtx m)
 instance (HasServerConfigCtx m)
         => HasServerConfigCtx (MetadataT m) where
  askServerConfigCtx = lift askServerConfigCtx
-instance (HasServerConfigCtx m)
-         => HasServerConfigCtx (LazyTxT QErr m) where
-  askServerConfigCtx = lift askServerConfigCtx
 instance (HasServerConfigCtx m) => HasServerConfigCtx (Q.TxET QErr m) where
  askServerConfigCtx = lift askServerConfigCtx
 instance (HasServerConfigCtx m) => HasServerConfigCtx (TableCacheRT b m) where
--- a/server/src-lib/Hasura/RQL/Types/Run.hs
+++ b/server/src-lib/Hasura/RQL/Types/Run.hs
@ -3,13 +3,11 @@
 module Hasura.RQL.Types.Run
  ( RunT(..)
  , RunCtx(..)
-  , runQueryLazyTx
  , peelRun
  ) where

 import           Hasura.Prelude

-import qualified Database.PG.Query            as Q
 import qualified Network.HTTP.Client.Extended as HTTP

 import           Control.Monad.Trans.Control  (MonadBaseControl)
@ -60,26 +58,6 @@ instance (Monad m) => HasServerConfigCtx (RunT m) where
 instance (MonadResolveSource m) => MonadResolveSource (RunT m) where
  getSourceResolver = RunT . lift . lift $ getSourceResolver

-runQueryLazyTx
-  :: ( MonadIO m
-     , MonadBaseControl IO m
-     , MonadError QErr m
-     , Tracing.MonadTrace m
-     , UserInfoM m
-     )
-  => PGExecCtx
-  -> Q.TxAccess
-  -> LazyTxT QErr m a
-  -> m a
-runQueryLazyTx pgExecCtx txAccess tx = do
-  traceCtx <- Tracing.currentContext
-  userInfo <- askUserInfo
-  liftEitherM
-    $ runExceptT
-    $ runLazyTx pgExecCtx txAccess
-    $ withTraceContext traceCtx
-    $ withUserInfo userInfo tx
-
 peelRun
  :: RunCtx
  -> RunT m a
--- a/server/src-lib/Hasura/RQL/Types/SchemaCache.hs
+++ b/server/src-lib/Hasura/RQL/Types/SchemaCache.hs
@ -139,6 +139,7 @@ import           Data.Int                                    (Int64)
 import           Data.Text.Extended
 import           System.Cron.Types

+import qualified Database.PG.Query                           as Q
 import qualified Hasura.Backends.Postgres.Connection         as PG
 import qualified Hasura.GraphQL.Parser                       as P
 import qualified Hasura.SQL.AnyBackend                       as AB
@ -464,7 +465,7 @@ instance (Monoid w, CacheRM m) => CacheRM (WriterT w m) where
  askSchemaCache = lift askSchemaCache
 instance (CacheRM m) => CacheRM (TraceT m) where
  askSchemaCache = lift askSchemaCache
-instance (CacheRM m) => CacheRM (PG.LazyTxT QErr m) where
+instance (CacheRM m) => CacheRM (Q.TxET QErr m) where
  askSchemaCache = lift askSchemaCache

 getDependentObjs :: SchemaCache -> SchemaObjId -> [SchemaObjId]
--- a/server/src-lib/Hasura/RQL/Types/SchemaCache/Build.hs
+++ b/server/src-lib/Hasura/RQL/Types/SchemaCache/Build.hs
@ -43,6 +43,7 @@ import           Network.HTTP.Client.Extended

 import qualified Hasura.Tracing                      as Tracing

+import qualified Database.PG.Query                   as Q
 import           Hasura.Backends.Postgres.Connection
 import           Hasura.Base.Error
 import           Hasura.RQL.Types.Common
@ -161,7 +162,7 @@ instance (CacheRWM m) => CacheRWM (StateT s m) where
 instance (CacheRWM m) => CacheRWM (TraceT m) where
  buildSchemaCacheWithOptions a b c = lift $ buildSchemaCacheWithOptions a b c
  setMetadataResourceVersionInSchemaCache = lift . setMetadataResourceVersionInSchemaCache
-instance (CacheRWM m) => CacheRWM (LazyTxT QErr m) where
+instance (CacheRWM m) => CacheRWM (Q.TxET QErr m) where
  buildSchemaCacheWithOptions a b c = lift $ buildSchemaCacheWithOptions a b c
  setMetadataResourceVersionInSchemaCache = lift . setMetadataResourceVersionInSchemaCache

--- a/server/src-lib/Hasura/RQL/Types/Source.hs
+++ b/server/src-lib/Hasura/RQL/Types/Source.hs
@ -12,6 +12,7 @@ import           Data.Aeson.Extended
 import qualified Hasura.SQL.AnyBackend               as AB
 import qualified Hasura.Tracing                      as Tracing

+import qualified Database.PG.Query                   as Q
 import           Hasura.Backends.Postgres.Connection
 import           Hasura.Base.Error
 import           Hasura.RQL.IR.BoolExp
@ -97,5 +98,5 @@ instance (MonadResolveSource m) => MonadResolveSource (ReaderT r m) where
 instance (MonadResolveSource m) => MonadResolveSource (Tracing.TraceT m) where
  getSourceResolver = lift getSourceResolver

-instance (MonadResolveSource m) => MonadResolveSource (LazyTxT QErr m) where
+instance (MonadResolveSource m) => MonadResolveSource (Q.TxET QErr m) where
  getSourceResolver = lift getSourceResolver
--- a/server/src-lib/Hasura/Server/App.hs
+++ b/server/src-lib/Hasura/Server/App.hs
@ -632,18 +632,8 @@ gqlExplainHandler
  -> m (HttpResponse EncJSON)
 gqlExplainHandler query = do
  onlyAdmin
-  scRef     <- asks (scCacheRef . hcServerCtx)
-  sc        <- getSCFromRef scRef
--  sqlGenCtx <- asks (scSQLGenCtx . hcServerCtx)
--  env       <- asks (scEnvironment . hcServerCtx)
--  logger    <- asks (scLogger . hcServerCtx)
-
-
-  -- let runTx :: ReaderT HandlerCtx (Tracing.TraceT (Tracing.NoReporter (LazyTx QErr))) a
-  --           -> ExceptT QErr (ReaderT HandlerCtx (Tracing.TraceT m)) a
-  -- let runTx rttx = ExceptT . ReaderT $ \ctx -> do
-  --       runExceptT (Tracing.interpTraceT (runLazyTx pgExecCtx Q.ReadOnly) (runReaderT rttx ctx))
-
+  scRef <- asks (scCacheRef . hcServerCtx)
+  sc <- getSCFromRef scRef
  res <- GE.explainGQLQuery sc query
  return $ HttpResponse res []

--- a/server/src-lib/Hasura/Server/Migrate.hs
+++ b/server/src-lib/Hasura/Server/Migrate.hs
@ -132,7 +132,7 @@ migrateCatalog maybeDefaultSourceConfig maintenanceMode migrationTime = do
      liftTx $ Q.catchE defaultTxErrorHandler $
        when createSchema $ Q.unitQ "CREATE SCHEMA hdb_catalog" () False
      enablePgcryptoExtension
-      runTx $(makeRelativeToProject "src-rsr/initialise.sql" >>= Q.sqlFromFile)
+      multiQ $(makeRelativeToProject "src-rsr/initialise.sql" >>= Q.sqlFromFile)
      updateCatalogVersion

      let emptyMetadata' = case maybeDefaultSourceConfig of
@ -263,7 +263,7 @@ migrations maybeDefaultSourceConfig dryRun maintenanceMode =
    runTxOrPrint
      | dryRun =
          liftIO . TIO.putStrLn . Q.getQueryText
-      | otherwise = runTx
+      | otherwise = multiQ

    from42To43 = do
      when (maintenanceMode == MaintenanceModeEnabled) $
@ -272,7 +272,7 @@ migrations maybeDefaultSourceConfig dryRun maintenanceMode =
      if dryRun then (liftIO . TIO.putStrLn . Q.getQueryText) query
        else do
        metadataV2 <- fetchMetadataFromHdbTables
-        runTx query
+        multiQ query
        defaultSourceConfig <- onNothing maybeDefaultSourceConfig $ throw400 NotSupported $
          "cannot migrate to catalog version 43 without --database-url or env var " <> tshow (fst databaseUrlEnv)
        let metadataV3 =
@ -289,7 +289,7 @@ migrations maybeDefaultSourceConfig dryRun maintenanceMode =
      if dryRun then (liftIO . TIO.putStrLn . Q.getQueryText) query
        else do
        Metadata{..} <- liftTx fetchMetadataFromCatalog
-        runTx query
+        multiQ query
        let emptyMetadataNoSources =
              MetadataNoSources mempty mempty mempty mempty mempty emptyCustomTypes mempty mempty
        metadataV2 <- case OMap.toList _metaSources of
@ -310,3 +310,6 @@ migrations maybeDefaultSourceConfig dryRun maintenanceMode =
          -- cron triggers are added in the `hdb_catalog.hdb_cron_triggers`
          addCronTriggerForeignKeyConstraint
        recreateSystemMetadata
+
+multiQ :: (MonadTx m) => Q.Query -> m ()
+multiQ = liftTx . Q.multiQE defaultTxErrorHandler
--- a/server/src-lib/Hasura/Server/Migrate/Internal.hs
+++ b/server/src-lib/Hasura/Server/Migrate/Internal.hs
@ -1,6 +1,5 @@
 module Hasura.Server.Migrate.Internal
-  ( runTx
-  , getCatalogVersion
+  ( getCatalogVersion
  , from3To4
  , setCatalogVersion
  ) where
@ -20,9 +19,6 @@ import           Hasura.RQL.Types.EventTrigger
 import           Hasura.SQL.Backend


-runTx :: (MonadTx m) => Q.Query -> m ()
-runTx = liftTx . Q.multiQE defaultTxErrorHandler
-
 -- | The old 0.8 catalog version is non-integral, so we store it in the database as a
 -- string.
 getCatalogVersion :: Q.TxE QErr Text
--- a/server/src-test/Hasura/Server/MigrateSpec.hs
+++ b/server/src-test/Hasura/Server/MigrateSpec.hs
@ -90,12 +90,12 @@ spec
  => PostgresConnConfiguration -> PGExecCtx -> Q.ConnInfo -> SpecWithCache m
 spec srcConfig pgExecCtx pgConnInfo = do
  let migrateCatalogAndBuildCache env time = do
-        (migrationResult, metadata) <- runTx pgExecCtx $ migrateCatalog (Just srcConfig) MaintenanceModeDisabled time
+        (migrationResult, metadata) <- runTx' pgExecCtx $ migrateCatalog (Just srcConfig) MaintenanceModeDisabled time
        (,migrationResult) <$> runCacheBuildM (buildRebuildableSchemaCache env metadata)

      dropAndInit env time = lift $ CacheRefT $ flip modifyMVar \_ ->
-        (runTx pgExecCtx dropHdbCatalogSchema) *> (migrateCatalogAndBuildCache env time)
-      downgradeTo v = runTx pgExecCtx . downgradeCatalog (Just srcConfig) DowngradeOptions{ dgoDryRun = False, dgoTargetVersion = v }
+        (runTx' pgExecCtx dropHdbCatalogSchema) *> (migrateCatalogAndBuildCache env time)
+      downgradeTo v = runTx' pgExecCtx . downgradeCatalog (Just srcConfig) DowngradeOptions{ dgoDryRun = False, dgoTargetVersion = v }

  describe "migrateCatalog" $ do
    it "initializes the catalog" $ singleTransaction do
@ -155,7 +155,7 @@ spec srcConfig pgExecCtx pgConnInfo = do
        MRMigrated{} -> True
        _            -> False
      firstDump <- transact dumpMetadata
-      transact (runTx pgExecCtx recreateSystemMetadata)
+      transact (runTx' pgExecCtx recreateSystemMetadata)
      secondDump <- transact dumpMetadata
      secondDump `shouldBe` firstDump

@ -168,7 +168,7 @@ spec srcConfig pgExecCtx pgConnInfo = do
      secondDump <- transact dumpMetadata
      secondDump `shouldBe` firstDump

-runTx
+runTx'
  :: (MonadError QErr m, MonadIO m, MonadBaseControl IO m)
-  => PGExecCtx -> LazyTxT QErr m a -> m a
-runTx pgExecCtx = liftEitherM . runExceptT . runLazyTx pgExecCtx Q.ReadWrite
+  => PGExecCtx -> Q.TxET QErr m a -> m a
+runTx' pgExecCtx = liftEitherM . runExceptT . runTx pgExecCtx Q.ReadWrite
--- a/server/src-test/Main.hs
+++ b/server/src-test/Main.hs
@ -156,7 +156,7 @@ buildPostgresSpecs maybeUrlTemplate = do
              >=> flip onLeft printErrJExit

        (metadata, schemaCache) <- run do
-          metadata <- snd <$> (liftEitherM . runExceptT . runLazyTx pgContext Q.ReadWrite)
+          metadata <- snd <$> (liftEitherM . runExceptT . runTx pgContext Q.ReadWrite)
                      (migrateCatalog (Just sourceConfig) maintenanceMode =<< liftIO getCurrentTime)
          schemaCache <- lift $ lift $ buildRebuildableSchemaCache envMap metadata
          pure (metadata, schemaCache)