module Hasura.Backends.Postgres.Execute.Mutation ( MutationRemoteJoinCtx , MutateResp(..) -- , execDeleteQuery , execInsertQuery , execUpdateQuery -- , executeMutationOutputQuery , mutateAndFetchCols ) where import Hasura.Prelude import qualified Data.Sequence as DS import qualified Database.PG.Query as Q import qualified Network.HTTP.Client as HTTP import qualified Network.HTTP.Types as N import Data.Aeson import qualified Hasura.Backends.Postgres.SQL.DML as S import Hasura.Backends.Postgres.Connection import Hasura.Backends.Postgres.SQL.Types import Hasura.Backends.Postgres.SQL.Value import Hasura.Backends.Postgres.Translate.Delete import Hasura.Backends.Postgres.Translate.Insert import Hasura.Backends.Postgres.Translate.Mutation import Hasura.Backends.Postgres.Translate.Returning import Hasura.Backends.Postgres.Translate.Select import Hasura.Backends.Postgres.Translate.Update import Hasura.Base.Error import Hasura.Base.Instances () import Hasura.EncJSON import Hasura.RQL.DML.Internal import Hasura.RQL.IR.Delete import Hasura.RQL.IR.Insert import Hasura.RQL.IR.Returning import Hasura.RQL.IR.Select import Hasura.RQL.IR.Update import Hasura.RQL.Types import Hasura.SQL.Types import Hasura.Session data MutateResp (b :: BackendType) a = MutateResp { _mrAffectedRows :: !Int , _mrReturningColumns :: ![ColumnValues b a] } deriving (Generic) deriving instance (Backend b, Show a) => Show (MutateResp b a) deriving instance (Backend b, Eq a) => Eq (MutateResp b a) instance (Backend b, ToJSON a) => ToJSON (MutateResp b a) where toJSON = genericToJSON hasuraJSON instance (Backend b, FromJSON a) => FromJSON (MutateResp b a) where parseJSON = genericParseJSON hasuraJSON type MutationRemoteJoinCtx = (HTTP.Manager, [N.Header], UserInfo) data Mutation (b :: BackendType) = Mutation { _mTable :: !QualifiedTable , _mQuery :: !(MutationCTE, DS.Seq Q.PrepArg) , _mOutput :: !(MutationOutput b) , _mCols :: ![ColumnInfo b] , _mStrfyNum :: !Bool } mkMutation :: UserInfo -> QualifiedTable -> (MutationCTE, DS.Seq Q.PrepArg) -> MutationOutput ('Postgres pgKind) -> [ColumnInfo ('Postgres pgKind)] -> Bool -> Mutation ('Postgres pgKind) mkMutation _userInfo table query output allCols strfyNum = Mutation table query output allCols strfyNum runMutation :: ( MonadTx m , Backend ('Postgres pgKind) , PostgresAnnotatedFieldJSON pgKind ) => Mutation ('Postgres pgKind) -> m EncJSON runMutation mut = bool (mutateAndReturn mut) (mutateAndSel mut) $ hasNestedFld $ _mOutput mut mutateAndReturn :: ( MonadTx m , Backend ('Postgres pgKind) , PostgresAnnotatedFieldJSON pgKind ) => Mutation ('Postgres pgKind) -> m EncJSON mutateAndReturn (Mutation qt (cte, p) mutationOutput allCols strfyNum) = executeMutationOutputQuery qt allCols Nothing cte mutationOutput strfyNum (toList p) execUpdateQuery :: ( MonadTx m , Backend ('Postgres pgKind) , PostgresAnnotatedFieldJSON pgKind ) => Bool -> UserInfo -> (AnnUpd ('Postgres pgKind), DS.Seq Q.PrepArg) -> m EncJSON execUpdateQuery strfyNum userInfo (u, p) = runMutation $ mkMutation userInfo (uqp1Table u) (MCCheckConstraint updateCTE, p) (uqp1Output u) (uqp1AllCols u) strfyNum where updateCTE = mkUpdateCTE u execDeleteQuery :: ( MonadTx m , Backend ('Postgres pgKind) , PostgresAnnotatedFieldJSON pgKind ) => Bool -> UserInfo -> (AnnDel ('Postgres pgKind), DS.Seq Q.PrepArg) -> m EncJSON execDeleteQuery strfyNum remoteJoinCtx (u, p) = runMutation $ mkMutation remoteJoinCtx (dqp1Table u) (MCDelete delete, p) (dqp1Output u) (dqp1AllCols u) strfyNum where delete = mkDelete u execInsertQuery :: ( MonadTx m , Backend ('Postgres pgKind) , PostgresAnnotatedFieldJSON pgKind ) => Bool -> UserInfo -> (InsertQueryP1 ('Postgres pgKind), DS.Seq Q.PrepArg) -> m EncJSON execInsertQuery strfyNum userInfo (u, p) = runMutation $ mkMutation userInfo (iqp1Table u) (MCCheckConstraint insertCTE, p) (iqp1Output u) (iqp1AllCols u) strfyNum where insertCTE = mkInsertCTE u {- Note: [Prepared statements in Mutations] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The SQL statements we generate for mutations seem to include the actual values in the statements in some cases which pretty much makes them unfit for reuse (Handling relationships in the returning clause is the source of this complexity). Further, `PGConn` has an internal cache which maps a statement to a 'prepared statement id' on Postgres. As we prepare more and more single-use SQL statements we end up leaking memory both on graphql-engine and Postgres till the connection is closed. So a simpler but very crude fix is to not use prepared statements for mutations. The performance of insert mutations shouldn't be affected but updates and delete mutations with complex boolean conditions **might** see some degradation. -} mutateAndSel :: forall pgKind m . ( MonadTx m , Backend ('Postgres pgKind) , PostgresAnnotatedFieldJSON pgKind ) => Mutation ('Postgres pgKind) -> m EncJSON mutateAndSel (Mutation qt q mutationOutput allCols strfyNum) = do -- Perform mutation and fetch unique columns MutateResp _ columnVals <- liftTx $ mutateAndFetchCols qt allCols q strfyNum select <- mkSelectExpFromColumnValues qt allCols columnVals -- Perform select query and fetch returning fields executeMutationOutputQuery qt allCols Nothing (MCSelectValues select) mutationOutput strfyNum [] withCheckPermission :: (MonadError QErr m) => m (a, Bool) -> m a withCheckPermission sqlTx = do (rawResponse, checkConstraint) <- sqlTx unless checkConstraint $ throw400 PermissionError $ "check constraint of an insert/update permission has failed" pure rawResponse executeMutationOutputQuery :: forall pgKind m . ( MonadTx m , Backend ('Postgres pgKind) , PostgresAnnotatedFieldJSON pgKind ) => QualifiedTable -> [ColumnInfo ('Postgres pgKind)] -> Maybe Int -> MutationCTE -> MutationOutput ('Postgres pgKind) -> Bool -> [Q.PrepArg] -- ^ Prepared params -> m EncJSON executeMutationOutputQuery qt allCols preCalAffRows cte mutOutput strfyNum prepArgs = do let queryTx :: Q.FromRes a => m a queryTx = do let selectWith = mkMutationOutputExp qt allCols preCalAffRows cte mutOutput strfyNum query = Q.fromBuilder $ toSQL selectWith -- See Note [Prepared statements in Mutations] liftTx (Q.rawQE dmlTxErrorHandler query prepArgs False) if checkPermissionRequired cte then withCheckPermission $ Q.getRow <$> queryTx else (runIdentity . Q.getRow) <$> queryTx mutateAndFetchCols :: forall pgKind . (Backend ('Postgres pgKind), PostgresAnnotatedFieldJSON pgKind) => QualifiedTable -> [ColumnInfo ('Postgres pgKind)] -> (MutationCTE, DS.Seq Q.PrepArg) -> Bool -> Q.TxE QErr (MutateResp ('Postgres pgKind) TxtEncodedVal) mutateAndFetchCols qt cols (cte, p) strfyNum = do let mutationTx :: Q.FromRes a => Q.TxE QErr a mutationTx = -- See Note [Prepared statements in Mutations] Q.rawQE dmlTxErrorHandler sqlText (toList p) False if checkPermissionRequired cte then withCheckPermission $ (first Q.getAltJ . Q.getRow) <$> mutationTx else (Q.getAltJ . runIdentity . Q.getRow) <$> mutationTx where aliasIdentifier = Identifier $ qualifiedObjectToText qt <> "__mutation_result" tabFrom = FromIdentifier aliasIdentifier tabPerm = TablePerm annBoolExpTrue Nothing selFlds = flip map cols $ \ci -> (fromCol @('Postgres pgKind) $ pgiColumn ci, mkAnnColumnFieldAsText ci) sqlText = Q.fromBuilder $ toSQL selectWith selectWith = S.SelectWith [(S.Alias aliasIdentifier, getMutationCTE cte)] select select = S.mkSelect { S.selExtr = S.Extractor extrExp Nothing : bool [] [S.Extractor checkErrExp Nothing] (checkPermissionRequired cte) } checkErrExp = mkCheckErrorExp aliasIdentifier extrExp = S.applyJsonBuildObj [ S.SELit "affected_rows", affRowsSel , S.SELit "returning_columns", colSel ] affRowsSel = S.SESelect $ S.mkSelect { S.selExtr = [S.Extractor S.countStar Nothing] , S.selFrom = Just $ S.FromExp [S.FIIdentifier aliasIdentifier] } colSel = S.SESelect $ mkSQLSelect JASMultipleRows $ AnnSelectG selFlds tabFrom tabPerm noSelectArgs strfyNum