-- | Translate from the DML to the BigQuery dialect. module Hasura.Backends.BigQuery.FromIr ( mkSQLSelect, fromRootField, fromSelectAggregate, Error (..), runFromIr, FromIr, FromIrConfig (..), defaultFromIrConfig, bigQuerySourceConfigToFromIrConfig, Top (..), -- Re-export for FromIrConfig. ) where import Control.Monad.Validate import Data.HashMap.Strict qualified as HM import Data.Int qualified as Int import Data.List.Extended (appendToNonEmpty) import Data.List.NonEmpty qualified as NE import Data.Map.Strict (Map) import Data.Map.Strict qualified as M import Data.Text qualified as T import Hasura.Backends.BigQuery.Instances.Types () import Hasura.Backends.BigQuery.Source (BigQuerySourceConfig (..)) import Hasura.Backends.BigQuery.Types as BigQuery import Hasura.Prelude import Hasura.RQL.IR qualified as Ir import Hasura.RQL.Types.Column qualified as Rql import Hasura.RQL.Types.Common qualified as Rql import Hasura.RQL.Types.Function qualified as Rql import Hasura.RQL.Types.Relationships.Local qualified as Rql import Hasura.SQL.Backend -------------------------------------------------------------------------------- -- Types -- | Most of these errors should be checked for legitimacy. data Error = FromTypeUnsupported (Ir.SelectFromG 'BigQuery Expression) | NoOrderSpecifiedInOrderBy | MalformedAgg | FieldTypeUnsupportedForNow (Ir.AnnFieldG 'BigQuery Void Expression) | AggTypeUnsupportedForNow (Ir.TableAggregateFieldG 'BigQuery Void Expression) | NodesUnsupportedForNow (Ir.TableAggregateFieldG 'BigQuery Void Expression) | NoProjectionFields | NoAggregatesMustBeABug | UnsupportedArraySelect (Ir.ArraySelectG 'BigQuery Void Expression) | UnsupportedOpExpG (Ir.OpExpG 'BigQuery Expression) | UnsupportedSQLExp Expression | UnsupportedDistinctOn | UnexpectedEmptyList | InvalidIntegerishSql Expression | ConnectionsNotSupported | ActionsNotSupported | -- | https://github.com/hasura/graphql-engine/issues/8526 ComputedFieldsBooleanExpressionNotSupported | -- | https://github.com/hasura/graphql-engine/issues/8526 ComputedFieldsOrderByNotSupported | -- | https://github.com/hasura/graphql-engine/issues/8521 ScalarComputedFieldsNotSupported | NoParentEntityInternalError instance Show Error where show = \case FromTypeUnsupported {} -> "FromTypeUnsupported" NoOrderSpecifiedInOrderBy {} -> "NoOrderSpecifiedInOrderBy" MalformedAgg {} -> "MalformedAgg" FieldTypeUnsupportedForNow {} -> "FieldTypeUnsupportedForNow" AggTypeUnsupportedForNow {} -> "AggTypeUnsupportedForNow" NodesUnsupportedForNow {} -> "NodesUnsupportedForNow" NoProjectionFields {} -> "NoProjectionFields" NoAggregatesMustBeABug {} -> "NoAggregatesMustBeABug" UnsupportedArraySelect {} -> "UnsupportedArraySelect" UnsupportedOpExpG {} -> "UnsupportedOpExpG" UnsupportedSQLExp {} -> "UnsupportedSQLExp" UnsupportedDistinctOn {} -> "UnsupportedDistinctOn" UnexpectedEmptyList {} -> "UnexpectedEmptyList" InvalidIntegerishSql {} -> "InvalidIntegerishSql" ConnectionsNotSupported {} -> "ConnectionsNotSupported" ActionsNotSupported {} -> "ActionsNotSupported" ComputedFieldsBooleanExpressionNotSupported {} -> "ComputedFieldsBooleanExpressionNotSupported" ComputedFieldsOrderByNotSupported {} -> "ComputedFieldsOrderByNotSupported" ScalarComputedFieldsNotSupported {} -> "ScalarComputedFieldsNotSupported" NoParentEntityInternalError {} -> "NoParentEntityInternalError" -- | The base monad used throughout this module for all conversion -- functions. -- -- It's a Validate, so it'll continue going when it encounters errors -- to accumulate as many as possible. -- -- It also contains a mapping from entity prefixes to counters. So if -- my prefix is "table" then there'll be a counter that lets me -- generate table1, table2, etc. Same for any other prefix needed -- (e.g. names for joins). -- -- A ReaderT is used around this in most of the module too, for -- setting the current entity that a given field name refers to. See -- @fromColumn@. newtype FromIr a = FromIr { unFromIr :: ReaderT FromIrReader (StateT FromIrState (Validate (NonEmpty Error))) a } deriving (Functor, Applicative, Monad, MonadValidate (NonEmpty Error)) data FromIrState = FromIrState { indices :: Map Text Int } data FromIrReader = FromIrReader { config :: FromIrConfig } -- | Config values for the from-IR translator. data FromIrConfig = FromIrConfig { -- | Applies globally to all selects, and may be reduced to -- something even smaller by permission/user args. globalSelectLimit :: Top } -- | A default config. defaultFromIrConfig :: FromIrConfig defaultFromIrConfig = FromIrConfig {globalSelectLimit = NoTop} -- | Alias of parent SELECT FROM. -- Functions underlying computed fields requires column values from -- the table that is being used in FROM clause of parent SELECT. -- -- Example SQL: -- -- > SELECT -- > `t_author1`.`id` AS `id`, -- > `t_author1`.`name` AS `name`, -- > ARRAY( -- > SELECT -- > AS STRUCT `id`, -- > `title`, -- > `content` -- > FROM -- > UNNEST( -- > ARRAY( -- > SELECT -- > AS STRUCT * -- > FROM `hasura_test`.`fetch_articles`(`id` => `t_author1`.`id`) -- > ) -- > ) -- > LIMIT 1000 -- > ) AS `articles` -- > FROM -- > `hasura_test`.`author` AS `t_author1` -- -- Where `t_author1` is the @'ParentSelectFromIdentity' data ParentSelectFromEntity = -- | There's no parent entity NoParentEntity | -- | Alias of the parent SELECT FROM ParentEntityAlias EntityAlias -------------------------------------------------------------------------------- -- Runners runFromIr :: FromIrConfig -> FromIr a -> Validate (NonEmpty Error) a runFromIr config fromIr = evalStateT (runReaderT (unFromIr fromIr) (FromIrReader {config})) (FromIrState {indices = mempty}) bigQuerySourceConfigToFromIrConfig :: BigQuerySourceConfig -> FromIrConfig bigQuerySourceConfigToFromIrConfig BigQuerySourceConfig {_scGlobalSelectLimit} = FromIrConfig {globalSelectLimit = Top _scGlobalSelectLimit} -------------------------------------------------------------------------------- -- Similar rendition of old API -- | Here is where we apply a top-level annotation to the select to -- indicate to the data loader that this select ought to produce a -- single object or an array. mkSQLSelect :: Rql.JsonAggSelect -> Ir.AnnSelectG 'BigQuery (Ir.AnnFieldG 'BigQuery Void) Expression -> FromIr BigQuery.Select mkSQLSelect jsonAggSelect annSimpleSel = do select <- noExtraPartitionFields <$> fromSelectRows NoParentEntity annSimpleSel pure ( select { selectCardinality = case jsonAggSelect of Rql.JASMultipleRows -> Many Rql.JASSingleObject -> One } ) -- | Convert from the IR database query into a select. fromRootField :: Ir.QueryDB 'BigQuery Void Expression -> FromIr Select fromRootField = \case (Ir.QDBSingleRow s) -> mkSQLSelect Rql.JASSingleObject s (Ir.QDBMultipleRows s) -> mkSQLSelect Rql.JASMultipleRows s (Ir.QDBAggregation s) -> fromSelectAggregate Nothing s -------------------------------------------------------------------------------- -- Top-level exported functions fromUnnestedJSON :: Expression -> [(ColumnName, ScalarType)] -> [Rql.FieldName] -> FromIr From fromUnnestedJSON json columns _fields = do alias <- generateEntityAlias UnnestTemplate pure ( FromSelectJson ( Aliased { aliasedThing = SelectJson { selectJsonBody = json, selectJsonFields = columns }, aliasedAlias = entityAliasText alias } ) ) fromSelectRows :: ParentSelectFromEntity -> Ir.AnnSelectG 'BigQuery (Ir.AnnFieldG 'BigQuery Void) Expression -> FromIr BigQuery.PartitionableSelect fromSelectRows parentSelectFromEntity annSelectG = do let Ir.AnnSelectG { _asnFields = fields, _asnFrom = from, _asnPerm = perm, _asnArgs = args, _asnNamingConvention = _tCase } = annSelectG Ir.TablePerm {_tpLimit = mPermLimit, _tpFilter = permFilter} = perm permissionBasedTop = maybe NoTop (Top . fromIntegral) mPermLimit selectFrom <- case from of Ir.FromTable qualifiedObject -> fromQualifiedTable qualifiedObject Ir.FromFunction nm (Rql.FunctionArgsExp [BigQuery.AEInput json] _) (Just columns) | functionName nm == "unnest" -> fromUnnestedJSON json columns (map fst fields) Ir.FromFunction functionName (Rql.FunctionArgsExp positionalArgs namedArgs) Nothing -> fromFunction parentSelectFromEntity functionName positionalArgs namedArgs _ -> refute (pure (FromTypeUnsupported from)) Args { argsOrderBy, argsWhere, argsJoins, argsTop, argsDistinct, argsOffset, argsExistingJoins } <- runReaderT (fromSelectArgsG args) (fromAlias selectFrom) fieldSources <- runReaderT (traverse (fromAnnFieldsG argsExistingJoins) fields) (fromAlias selectFrom) filterExpression <- runReaderT (fromAnnBoolExp permFilter) (fromAlias selectFrom) selectProjections <- selectProjectionsFromFieldSources True fieldSources globalTop <- getGlobalTop let select = Select { selectCardinality = Many, selectAsStruct = NoAsStruct, selectFinalWantedFields = pure (fieldTextNames fields), selectGroupBy = mempty, selectOrderBy = argsOrderBy, -- We DO APPLY the global top here, because this pulls down all rows. selectTop = globalTop <> permissionBasedTop <> argsTop, selectProjections, selectFrom, selectJoins = argsJoins <> concat (mapMaybe fieldSourceJoins fieldSources), selectWhere = argsWhere <> Where [filterExpression], selectOffset = int64Expr <$> argsOffset } case argsDistinct of Nothing -> pure $ simpleSelect select Just distinct -> simulateDistinctOn select distinct argsOrderBy -- | Simulates DISTINCT ON for BigQuery using ROW_NUMBER() partitioned over distinct fields -- -- Example: -- -- For a GraphQL query: -- @ -- hasura_test_article(distinct_on: author_id, order_by: [{author_id: asc}, {created_at: asc}]) { -- id -- title -- } -- @ -- -- it should produce from a query without a `distinct_on` clause: -- -- SELECT `id`, `title` -- FROM `hasura_test`.`article` -- ORDER BY `author_id` ASC, `created_at` ASC -- -- a query of the following form: -- -- SELECT `id`, `title` -- FROM (SELECT *, -- ROW_NUMBER() OVER (PARTITION BY `author_id` ORDER BY `created_at` ASC) as `idx1` -- FROM `hasura_test`.`article`) as `t_article1` -- WHERE (`t_article1`.`idx1` = 1) -- ORDER BY `t_article1`.`author_id` ASC -- -- Note: this method returns PartitionableSelect as it could be joined using an array relation -- which requires extra fields added to the PARTITION BY clause to return proper results simulateDistinctOn :: Select -> NonEmpty ColumnName -> Maybe (NonEmpty OrderBy) -> FromIr PartitionableSelect simulateDistinctOn select distinctOnColumns orderByColumns = do rowNumAlias <- generateEntityAlias IndexTemplate pure PartitionableSelect { pselectFrom = selectFrom select, pselectFinalize = \mExtraPartitionField -> let -- we use the same alias both for outer and inner selects alias = entityAliasText (fromAlias (selectFrom select)) distinctFields = fmap (\(ColumnName name) -> FieldName name alias) distinctOnColumns finalDistinctFields = case mExtraPartitionField of Just extraFields | Just neExtraFields <- nonEmpty extraFields -> neExtraFields <> distinctFields _ -> distinctFields (distinctOnOrderBy, innerOrderBy) = case orderByColumns of Just orderBy -> let (distincts, others) = NE.partition (\OrderBy {..} -> orderByFieldName `elem` distinctFields) orderBy in (NE.nonEmpty distincts, NE.nonEmpty others) Nothing -> (Nothing, Nothing) innerFrom = FromSelect Aliased { aliasedAlias = alias, aliasedThing = select { selectProjections = StarProjection :| [ WindowProjection ( Aliased { aliasedAlias = unEntityAlias rowNumAlias, aliasedThing = RowNumberOverPartitionBy finalDistinctFields innerOrderBy -- Above: Having the order by -- in here ensures that we get the proper -- row as the first one we select -- in the outer select WHERE condition -- to simulate DISTINCT ON semantics } ) ], selectTop = mempty, selectJoins = mempty, selectOrderBy = mempty, selectOffset = Nothing, selectGroupBy = mempty, selectFinalWantedFields = mempty } } in select { selectFrom = innerFrom, selectWhere = Where [ EqualExpression (ColumnExpression FieldName {fieldNameEntity = alias, fieldName = unEntityAlias rowNumAlias}) (int64Expr 1) ], selectOrderBy = distinctOnOrderBy } } fromSelectAggregate :: Maybe (EntityAlias, HashMap ColumnName ColumnName) -> Ir.AnnSelectG 'BigQuery (Ir.TableAggregateFieldG 'BigQuery Void) Expression -> FromIr BigQuery.Select fromSelectAggregate minnerJoinFields annSelectG = do selectFrom <- case from of Ir.FromTable qualifiedObject -> fromQualifiedTable qualifiedObject _ -> refute (pure (FromTypeUnsupported from)) args'@Args {argsWhere, argsOrderBy, argsJoins, argsTop, argsOffset, argsDistinct} <- runReaderT (fromSelectArgsG args) (fromAlias selectFrom) filterExpression <- runReaderT (fromAnnBoolExp permFilter) (fromAlias selectFrom) mforeignKeyConditions <- for minnerJoinFields $ \(entityAlias, mapping) -> runReaderT (fromMappingFieldNames (fromAlias selectFrom) mapping) entityAlias fieldSources <- runReaderT ( traverse ( fromTableAggregateFieldG args' permissionBasedTop ) fields ) (fromAlias selectFrom) selectProjections <- selectProjectionsFromFieldSources True fieldSources indexAlias <- generateEntityAlias IndexTemplate let innerSelectAlias = entityAliasText (fromAlias selectFrom) mDistinctFields = fmap (fmap (\(ColumnName name) -> FieldName name innerSelectAlias)) argsDistinct mPartitionFields = (mforeignKeyConditions >>= NE.nonEmpty . map fst) <> mDistinctFields innerProjections = case mPartitionFields of Nothing -> pure StarProjection Just partitionFields -> StarProjection :| -- We setup an index over every row in -- the sub select. Then if you look at -- the outer Select, you can see we apply -- a WHERE that uses this index for -- LIMIT/OFFSET or DISTINCT ON. [ WindowProjection ( Aliased { aliasedAlias = unEntityAlias indexAlias, aliasedThing = RowNumberOverPartitionBy -- The row numbers start from 1. partitionFields argsOrderBy -- Above: Having the order by -- in here ensures that the -- row numbers are ordered by -- this ordering. Below, we -- order again for the -- general row order. Both -- are needed! } ) ] indexColumn = ColumnExpression $ FieldName { fieldNameEntity = innerSelectAlias, fieldName = unEntityAlias indexAlias } pure Select { selectCardinality = One, selectAsStruct = NoAsStruct, selectFinalWantedFields = Nothing, selectGroupBy = mempty, selectProjections, selectTop = NoTop, selectFrom = FromSelect ( Aliased { aliasedThing = Select { selectProjections = innerProjections, selectAsStruct = NoAsStruct, selectFrom, selectJoins = argsJoins, selectWhere = argsWhere <> (Where [filterExpression]), selectOrderBy = argsOrderBy, -- Above: This is important to have here, because -- offset/top apply AFTER ordering is applied, so -- you can't put an order by in afterwards in a -- parent query. Therefore be careful about -- putting this elsewhere. selectFinalWantedFields = Nothing, selectCardinality = Many, selectTop = maybe argsTop (const NoTop) mforeignKeyConditions, -- we apply offset only if we don't have partitions -- when we do OFFSET/LIMIT based on ROW_NUMBER() selectOffset = maybe (int64Expr <$> argsOffset) (const Nothing) mPartitionFields, selectGroupBy = mempty }, aliasedAlias = innerSelectAlias } ), selectJoins = concat (mapMaybe fieldSourceJoins fieldSources), selectWhere = case mPartitionFields of Nothing -> mempty Just {} -> let offset = case argsDistinct of Nothing -> case argsOffset of Nothing -> mempty Just offset' -> -- Apply an offset using the row_number from above. [ OpExpression MoreOp indexColumn (int64Expr offset') ] Just {} -> -- in case of distinct_on we need to select the row number offset+1 -- effectively skipping number of rows equal to offset [ EqualExpression indexColumn (int64Expr (fromMaybe 0 argsOffset + 1)) ] limit = case argsTop of NoTop -> mempty Top limit' -> -- Apply a limit using the row_number from above. [ OpExpression LessOp indexColumn ( int64Expr (limit' + 1) -- Because the row_number() indexing starts at 1. -- So idx limit), selectOrderBy = Nothing, selectOffset = Nothing } where Ir.AnnSelectG { _asnFields = fields, _asnFrom = from, _asnPerm = perm, _asnArgs = args, _asnNamingConvention = _tCase } = annSelectG Ir.TablePerm {_tpLimit = mPermLimit, _tpFilter = permFilter} = perm permissionBasedTop = maybe NoTop (Top . fromIntegral) mPermLimit -------------------------------------------------------------------------------- -- GraphQL Args data Args = Args { argsWhere :: Where, argsOrderBy :: Maybe (NonEmpty OrderBy), argsJoins :: [Join], argsTop :: Top, argsOffset :: Maybe Int.Int64, argsDistinct :: Maybe (NonEmpty ColumnName), argsExistingJoins :: Map TableName EntityAlias } deriving (Show) data UnfurledJoin = UnfurledJoin { unfurledJoin :: Join, -- | Recorded if we joined onto an object relation. unfurledObjectTableAlias :: Maybe (TableName, EntityAlias) } deriving (Show) fromSelectArgsG :: Ir.SelectArgsG 'BigQuery Expression -> ReaderT EntityAlias FromIr Args fromSelectArgsG selectArgsG = do argsWhere <- maybe (pure mempty) (fmap (Where . pure) . fromAnnBoolExp) mannBoolExp let argsTop = maybe mempty (Top . fromIntegral) mlimit (argsOrderBy, joins) <- runWriterT (traverse fromAnnotatedOrderByItemG (maybe [] toList orders)) -- Any object-relation joins that we generated, we record their -- generated names into a mapping. let argsExistingJoins = M.fromList (mapMaybe unfurledObjectTableAlias (toList joins)) pure Args { argsJoins = toList (fmap unfurledJoin joins), argsOrderBy = NE.nonEmpty argsOrderBy, argsDistinct = mdistinct, .. } where Ir.SelectArgs { _saWhere = mannBoolExp, _saLimit = mlimit, _saOffset = argsOffset, _saDistinct = mdistinct, _saOrderBy = orders } = selectArgsG -- | Produce a valid ORDER BY construct, telling about any joins -- needed on the side. fromAnnotatedOrderByItemG :: Ir.AnnotatedOrderByItemG 'BigQuery Expression -> WriterT (Seq UnfurledJoin) (ReaderT EntityAlias FromIr) OrderBy fromAnnotatedOrderByItemG Ir.OrderByItemG {obiType, obiColumn, obiNulls} = do orderByFieldName <- unfurlAnnotatedOrderByElement obiColumn let morderByOrder = obiType let orderByNullsOrder = fromMaybe NullsAnyOrder obiNulls case morderByOrder of Just orderByOrder -> pure OrderBy {..} Nothing -> refute (pure NoOrderSpecifiedInOrderBy) -- | Unfurl the nested set of object relations (tell'd in the writer) -- that are terminated by field name (Ir.AOCColumn and -- Ir.AOCArrayAggregation). unfurlAnnotatedOrderByElement :: Ir.AnnotatedOrderByElement 'BigQuery Expression -> WriterT (Seq UnfurledJoin) (ReaderT EntityAlias FromIr) FieldName unfurlAnnotatedOrderByElement = \case Ir.AOCColumn columnInfo -> lift (fromColumnInfo columnInfo) Ir.AOCObjectRelation Rql.RelInfo {riMapping = mapping, riRTable = tableName} annBoolExp annOrderByElementG -> do selectFrom <- lift (lift (fromQualifiedTable tableName)) joinAliasEntity <- lift (lift (generateEntityAlias (ForOrderAlias (tableNameText tableName)))) joinOn <- lift (fromMappingFieldNames joinAliasEntity mapping) whereExpression <- lift (local (const (fromAlias selectFrom)) (fromAnnBoolExp annBoolExp)) tell ( pure UnfurledJoin { unfurledJoin = Join { joinSource = JoinSelect Select { selectCardinality = One, selectAsStruct = NoAsStruct, selectFinalWantedFields = Nothing, selectGroupBy = mempty, selectTop = NoTop, selectProjections = StarProjection :| [], selectFrom, selectJoins = [], selectWhere = Where ([whereExpression]), selectOrderBy = Nothing, selectOffset = Nothing }, joinRightTable = fromAlias selectFrom, joinAlias = joinAliasEntity, joinOn, joinProvenance = OrderByJoinProvenance, joinFieldName = tableNameText tableName, -- TODO: not needed. joinExtractPath = Nothing }, unfurledObjectTableAlias = Just (tableName, joinAliasEntity) } ) local (const joinAliasEntity) (unfurlAnnotatedOrderByElement annOrderByElementG) Ir.AOCArrayAggregation Rql.RelInfo {riMapping = mapping, riRTable = tableName} annBoolExp annAggregateOrderBy -> do selectFrom <- lift (lift (fromQualifiedTable tableName)) let alias = aggFieldName joinAlias <- lift (lift (generateEntityAlias (ForOrderAlias (tableNameText tableName)))) joinOn <- lift (fromMappingFieldNames joinAlias mapping) innerJoinFields <- lift (fromMappingFieldNames (fromAlias selectFrom) mapping) whereExpression <- lift (local (const (fromAlias selectFrom)) (fromAnnBoolExp annBoolExp)) aggregate <- lift ( local (const (fromAlias selectFrom)) ( case annAggregateOrderBy of Ir.AAOCount -> pure (CountAggregate StarCountable) Ir.AAOOp text _resultType columnInfo -> do fieldName <- fromColumnInfo columnInfo pure (OpAggregate text (ColumnExpression fieldName)) ) ) tell ( pure ( UnfurledJoin { unfurledJoin = Join { joinSource = JoinSelect Select { selectCardinality = One, selectAsStruct = NoAsStruct, selectFinalWantedFields = Nothing, selectTop = NoTop, selectProjections = AggregateProjection Aliased { aliasedThing = aggregate, aliasedAlias = alias } :| -- These are group by'd below in selectGroupBy. map ( \(fieldName', _) -> FieldNameProjection Aliased { aliasedThing = fieldName', aliasedAlias = fieldName fieldName' } ) innerJoinFields, selectFrom, selectJoins = [], selectWhere = Where [whereExpression], selectOrderBy = Nothing, selectOffset = Nothing, -- This group by corresponds to the field name projections above. selectGroupBy = map fst innerJoinFields }, joinRightTable = fromAlias selectFrom, joinProvenance = OrderByJoinProvenance, joinAlias = joinAlias, joinOn, joinFieldName = tableNameText tableName, -- TODO: not needed. joinExtractPath = Nothing }, unfurledObjectTableAlias = Nothing } ) ) pure FieldName { fieldNameEntity = entityAliasText joinAlias, fieldName = alias } Ir.AOCComputedField {} -> refute $ pure ComputedFieldsOrderByNotSupported -------------------------------------------------------------------------------- -- Conversion functions tableNameText :: TableName -> Text tableNameText (TableName {tableName = qname}) = qname -- | This is really the start where you query the base table, -- everything else is joins attached to it. fromQualifiedTable :: TableName -> FromIr From fromQualifiedTable (TableName {tableNameSchema = schemaName, tableName = qname}) = do alias <- generateEntityAlias (TableTemplate qname) pure ( FromQualifiedTable ( Aliased { aliasedThing = TableName {tableName = qname, tableNameSchema = schemaName}, aliasedAlias = entityAliasText alias } ) ) -- | Build a @'From' expression out of a function that returns a set of rows. fromFunction :: -- | The parent's entity alias from which the column values for computed fields are referred ParentSelectFromEntity -> -- | The function FunctionName -> -- | List of positional Arguments [ArgumentExp Expression] -> -- | List of named arguments HM.HashMap Text (ArgumentExp Expression) -> FromIr From fromFunction parentEntityAlias functionName positionalArgs namedArgs = do alias <- generateEntityAlias (FunctionTemplate functionName) positionalArgExps <- mapM fromArgumentExp positionalArgs namedArgExps <- for (HM.toList namedArgs) $ \(argName, argValue) -> FunctionNamedArgument argName <$> fromArgumentExp argValue pure ( FromFunction ( Aliased { aliasedThing = SelectFromFunction functionName (positionalArgExps <> namedArgExps), aliasedAlias = entityAliasText alias } ) ) where fromArgumentExp :: ArgumentExp Expression -> FromIr Expression fromArgumentExp = \case AEInput e -> pure e AETableColumn (ColumnName columnName) -> do case parentEntityAlias of NoParentEntity -> refute $ pure NoParentEntityInternalError ParentEntityAlias entityAlias -> pure $ ColumnExpression $ FieldName columnName (entityAliasText entityAlias) fromAnnBoolExp :: Ir.GBoolExp 'BigQuery (Ir.AnnBoolExpFld 'BigQuery Expression) -> ReaderT EntityAlias FromIr Expression fromAnnBoolExp = traverse fromAnnBoolExpFld >=> fromGBoolExp fromAnnBoolExpFld :: Ir.AnnBoolExpFld 'BigQuery Expression -> ReaderT EntityAlias FromIr Expression fromAnnBoolExpFld = \case Ir.AVColumn columnInfo opExpGs -> do expression <- fmap ColumnExpression (fromColumnInfo columnInfo) expressions <- traverse (lift . fromOpExpG expression) opExpGs pure (AndExpression expressions) Ir.AVRelationship Rql.RelInfo {riMapping = mapping, riRTable = table} annBoolExp -> do selectFrom <- lift (fromQualifiedTable table) foreignKeyConditions <- fromMapping selectFrom mapping whereExpression <- local (const (fromAlias selectFrom)) (fromAnnBoolExp annBoolExp) pure ( ExistsExpression Select { selectCardinality = One, selectAsStruct = NoAsStruct, selectFinalWantedFields = Nothing, selectGroupBy = mempty, selectOrderBy = Nothing, selectProjections = ExpressionProjection ( Aliased { aliasedThing = trueExpression, aliasedAlias = existsFieldName } ) :| [], selectFrom, selectJoins = mempty, selectWhere = Where (foreignKeyConditions <> [whereExpression]), selectTop = NoTop, selectOffset = Nothing } ) Ir.AVComputedField {} -> refute $ pure ComputedFieldsBooleanExpressionNotSupported fromColumnInfo :: Rql.ColumnInfo 'BigQuery -> ReaderT EntityAlias FromIr FieldName fromColumnInfo Rql.ColumnInfo {ciColumn = ColumnName column} = do EntityAlias {entityAliasText} <- ask pure ( FieldName { fieldName = column, fieldNameEntity = entityAliasText } ) fromGExists :: Ir.GExists 'BigQuery Expression -> ReaderT EntityAlias FromIr Select fromGExists Ir.GExists {_geTable, _geWhere} = do selectFrom <- lift (fromQualifiedTable _geTable) whereExpression <- local (const (fromAlias selectFrom)) (fromGBoolExp _geWhere) pure Select { selectCardinality = One, selectAsStruct = NoAsStruct, selectFinalWantedFields = Nothing, selectGroupBy = mempty, selectOrderBy = Nothing, selectProjections = ExpressionProjection ( Aliased { aliasedThing = trueExpression, aliasedAlias = existsFieldName } ) :| [], selectFrom, selectJoins = mempty, selectWhere = Where [whereExpression], selectTop = NoTop, selectOffset = Nothing } -------------------------------------------------------------------------------- -- Sources of projected fields -- -- Because in the IR, a field projected can be a foreign object, we -- have to both generate a projection AND on the side generate a join. -- -- So a @FieldSource@ couples the idea of the projected thing and the -- source of it (via 'Aliased'). data FieldSource = ExpressionFieldSource (Aliased Expression) | JoinFieldSource (Aliased Join) | AggregateFieldSource Text (NonEmpty (Aliased Aggregate)) | ArrayAggFieldSource (Aliased ArrayAgg) (Maybe [FieldSource]) deriving (Eq, Show) -- Example: -- -- @ -- Track_aggregate { -- aggregate { -- count(columns: AlbumId) -- foo: count(columns: AlbumId) -- max { -- AlbumId -- TrackId -- } -- } -- } -- @ -- -- field = -- @ -- TAFAgg -- [ ( FieldName {getFieldNameTxt = "count"} -- , AFCount (NonNullFieldCountable [ColumnName {columnName = "AlbumId"}])) -- , ( FieldName {getFieldNameTxt = "foo"} -- , AFCount (NonNullFieldCountable [ColumnName {columnName = "AlbumId"}])) -- , ( FieldName {getFieldNameTxt = "max"} -- , AFOp -- (AggregateOp -- { _aoOp = "max" -- , _aoFields = -- [ ( FieldName {getFieldNameTxt = "AlbumId"} -- , CFCol (ColumnName {columnName = "AlbumId"} (ColumnScalar IntegerScalarType))) -- , ( FieldName {getFieldNameTxt = "TrackId"} -- , CFCol (ColumnName {columnName = "TrackId"} (ColumnScalar IntegerScalarType))) -- ] -- })) -- ] -- @ -- -- should produce: -- -- SELECT COUNT(`t_Track1`.`AlbumId`) AS `count`, -- COUNT(`t_Track1`.`AlbumId`) AS `foo`, -- struct(max(`t_Track1`.`AlbumId`) AS `AlbumId`, max(`t_Track1`.`TrackId`) as TrackId) as `max` -- FROM chinook.`Track` AS `t_Track1` -- fromTableAggregateFieldG :: Args -> Top -> (Rql.FieldName, Ir.TableAggregateFieldG 'BigQuery Void Expression) -> ReaderT EntityAlias FromIr FieldSource fromTableAggregateFieldG args permissionBasedTop (Rql.FieldName name, field) = case field of Ir.TAFAgg (aggregateFields :: [(Rql.FieldName, Ir.AggregateField 'BigQuery)]) -> case NE.nonEmpty aggregateFields of Nothing -> refute (pure NoAggregatesMustBeABug) Just fields -> do aggregates <- traverse ( \(fieldName, aggregateField) -> do fmap ( \aliasedThing -> Aliased {aliasedAlias = Rql.getFieldNameTxt fieldName, ..} ) (fromAggregateField aggregateField) ) fields pure (AggregateFieldSource name aggregates) Ir.TAFExp text -> pure ( ExpressionFieldSource Aliased { aliasedThing = BigQuery.ValueExpression (StringValue text), aliasedAlias = name } ) Ir.TAFNodes _ (fields :: [(Rql.FieldName, Ir.AnnFieldG 'BigQuery Void Expression)]) -> do fieldSources <- traverse (fromAnnFieldsG (argsExistingJoins args)) fields arrayAggProjections <- lift (selectProjectionsFromFieldSources False fieldSources) globalTop <- lift getGlobalTop let arrayAgg = Aliased { aliasedThing = ArrayAgg { arrayAggProjections, arrayAggOrderBy = argsOrderBy args, arrayAggTop = globalTop <> argsTop args <> permissionBasedTop }, aliasedAlias = name } pure (ArrayAggFieldSource arrayAgg (Just fieldSources)) fromAggregateField :: Ir.AggregateField 'BigQuery -> ReaderT EntityAlias FromIr Aggregate fromAggregateField aggregateField = case aggregateField of Ir.AFExp text -> pure (TextAggregate text) Ir.AFCount countType -> CountAggregate <$> case countType of StarCountable -> pure StarCountable NonNullFieldCountable names -> NonNullFieldCountable <$> traverse fromColumn names DistinctCountable names -> DistinctCountable <$> traverse fromColumn names Ir.AFOp Ir.AggregateOp {_aoOp = op, _aoFields = fields} -> do fs <- NE.nonEmpty fields `onNothing` refute (pure MalformedAgg) args <- traverse ( \(Rql.FieldName fieldName, columnField) -> do expression' <- case columnField of Ir.CFCol column _columnType -> fmap ColumnExpression (fromColumn column) Ir.CFExp text -> pure (ValueExpression (StringValue text)) pure (fieldName, expression') ) fs pure (OpAggregates op args) -- | The main sources of fields, either constants, fields or via joins. fromAnnFieldsG :: Map TableName EntityAlias -> (Rql.FieldName, Ir.AnnFieldG 'BigQuery Void Expression) -> ReaderT EntityAlias FromIr FieldSource fromAnnFieldsG existingJoins (Rql.FieldName name, field) = case field of Ir.AFColumn annColumnField -> do expression <- fromAnnColumnField annColumnField pure ( ExpressionFieldSource Aliased {aliasedThing = expression, aliasedAlias = name} ) Ir.AFExpression text -> pure ( ExpressionFieldSource Aliased { aliasedThing = BigQuery.ValueExpression (StringValue text), aliasedAlias = name } ) Ir.AFObjectRelation objectRelationSelectG -> fmap ( \aliasedThing -> JoinFieldSource (Aliased {aliasedThing, aliasedAlias = name}) ) (fromObjectRelationSelectG existingJoins objectRelationSelectG) Ir.AFArrayRelation arraySelectG -> fmap ( \aliasedThing -> JoinFieldSource (Aliased {aliasedThing, aliasedAlias = name}) ) (fromArraySelectG arraySelectG) Ir.AFComputedField _ _ computedFieldSelect -> do expression <- fromComputedFieldSelect computedFieldSelect pure ( ExpressionFieldSource Aliased {aliasedThing = expression, aliasedAlias = name} ) -- | Here is where we project a field as a column expression. If -- number stringification is on, then we wrap it in a -- 'ToStringExpression' so that it's casted when being projected. fromAnnColumnField :: Ir.AnnColumnField 'BigQuery Expression -> ReaderT EntityAlias FromIr Expression fromAnnColumnField annColumnField = do fieldName <- fromColumn column if asText || False -- TODO: (Rql.isScalarColumnWhere Psql.isBigNum typ && stringifyNumbers == Rql.StringifyNumbers) then pure (ToStringExpression (ColumnExpression fieldName)) else case caseBoolExpMaybe of Nothing -> pure (ColumnExpression fieldName) Just ex -> do ex' <- (traverse fromAnnBoolExpFld >=> fromGBoolExp) (coerce ex) pure (ConditionalProjection ex' fieldName) where Ir.AnnColumnField { _acfColumn = column, _acfAsText = asText :: Bool, _acfArguments = _ :: Maybe Void, _acfCaseBoolExpression = caseBoolExpMaybe :: Maybe (Ir.AnnColumnCaseBoolExp 'BigQuery Expression) } = annColumnField -- | This is where a field name "foo" is resolved to a fully qualified -- field name [table].[foo]. The table name comes from EntityAlias in -- the ReaderT. fromColumn :: ColumnName -> ReaderT EntityAlias FromIr FieldName fromColumn (ColumnName txt) = do EntityAlias {entityAliasText} <- ask pure (FieldName {fieldName = txt, fieldNameEntity = entityAliasText}) fieldSourceProjections :: Bool -> FieldSource -> FromIr (NonEmpty Projection) fieldSourceProjections keepJoinField = \case ExpressionFieldSource aliasedExpression -> pure (ExpressionProjection aliasedExpression :| []) JoinFieldSource aliasedJoin -> toNonEmpty -- Here we're producing all join fields needed later for -- Haskell-native joining. They will be removed by upstream -- code if keepJoinField is True ( [ FieldNameProjection ( Aliased { aliasedThing = right, aliasedAlias = fieldNameText right } ) | keepJoinField, (_left, right) <- joinOn join' ] <> -- Below: -- When we're doing an array-aggregate, e.g. -- -- query MyQuery { -- hasura_Artist { -- albums_aggregate { -- aggregate { -- count -- } -- } -- } -- } -- -- we're going to do a join on the albums table, and that -- join query will produce a single-row result. Therefore we -- can grab the whole entity as a STRUCT-typed object. See -- also the docs for 'fromArrayRelationSelectG' and for -- 'fromArrayAggregateSelectG'. case joinProvenance join' of ArrayJoinProvenance fields -> pure ( ArrayEntityProjection (joinAlias join') aliasedJoin { aliasedThing = fmap ( \name -> FieldName { fieldName = name, fieldNameEntity = entityAliasText (joinAlias join') } ) fields, aliasedAlias = aliasedAlias aliasedJoin } ) ObjectJoinProvenance fields -> pure ( EntityProjection aliasedJoin { aliasedThing = fmap ( \name -> ( FieldName { fieldName = name, fieldNameEntity = entityAliasText (joinAlias join') }, NoOrigin ) ) fields, aliasedAlias = aliasedAlias aliasedJoin } ) ArrayAggregateJoinProvenance fields -> pure ( EntityProjection aliasedJoin { aliasedThing = fmap ( \(name, fieldOrigin) -> ( FieldName { fieldName = name, fieldNameEntity = entityAliasText (joinAlias join') }, fieldOrigin ) ) fields, aliasedAlias = aliasedAlias aliasedJoin } ) _ -> [] ) where join' = aliasedThing aliasedJoin AggregateFieldSource name aggregates -> pure ( AggregateProjections (Aliased {aliasedThing = aggregates, aliasedAlias = name}) :| [] ) ArrayAggFieldSource arrayAgg _ -> pure (ArrayAggProjection arrayAgg :| []) where fieldNameText FieldName {fieldName} = fieldName fieldSourceJoins :: FieldSource -> Maybe [Join] fieldSourceJoins = \case JoinFieldSource aliasedJoin -> pure [aliasedThing aliasedJoin] ExpressionFieldSource {} -> Nothing AggregateFieldSource {} -> Nothing ArrayAggFieldSource _ sources -> fmap (concat . mapMaybe fieldSourceJoins) sources -------------------------------------------------------------------------------- -- Joins -- | Produce the join for an object relation. We produce a normal -- select, but then include join fields. Then downstream, the -- DataLoader will execute the lhs select and rhs join in separate -- server queries, then do a Haskell-native join on the join fields. -- -- See also 'fromArrayRelationSelectG' for similar example. fromObjectRelationSelectG :: Map TableName EntityAlias -> Ir.ObjectRelationSelectG 'BigQuery Void Expression -> ReaderT EntityAlias FromIr Join -- We're not using existingJoins at the moment, which was used to -- avoid re-joining on the same table twice. fromObjectRelationSelectG _existingJoins annRelationSelectG = do selectFrom <- lift (fromQualifiedTable tableFrom) let entityAlias :: EntityAlias = fromAlias selectFrom fieldSources <- local (const entityAlias) (traverse (fromAnnFieldsG mempty) fields) selectProjections <- lift (selectProjectionsFromFieldSources True fieldSources) joinFieldName <- lift (fromRelName _aarRelationshipName) joinAlias <- lift (generateEntityAlias (ObjectRelationTemplate joinFieldName)) filterExpression <- local (const entityAlias) (fromAnnBoolExp tableFilter) -- @mapping@ here describes the pairs of columns that form foreign key -- relationships between tables. For example, when querying an "article" -- table for article titles and joining on an "authors" table for author -- names, we could end up with something like the following: -- -- @ -- [ ( ColumnName { columnName = "author_id" } -- , ColumnName { columnName = "id" } -- ) -- ] -- @ -- -- Note that the "local" table is on the left, and the "remote" table is on -- the right. joinFields <- fromMappingFieldNames (fromAlias selectFrom) mapping joinOn <- fromMappingFieldNames joinAlias mapping joinFieldProjections <- toNonEmpty (map prepareJoinFieldProjection joinFields) let selectFinalWantedFields = pure (fieldTextNames fields) pure Join { joinAlias, joinSource = JoinSelect Select { selectCardinality = One, selectAsStruct = NoAsStruct, selectFinalWantedFields, selectGroupBy = mempty, selectOrderBy = Nothing, selectTop = NoTop, selectProjections = joinFieldProjections <> selectProjections, selectFrom, selectJoins = concat (mapMaybe fieldSourceJoins fieldSources), selectWhere = Where [filterExpression], selectOffset = Nothing }, joinOn, joinRightTable = fromAlias selectFrom, joinProvenance = ObjectJoinProvenance (fromMaybe [] selectFinalWantedFields), -- TODO: OK? -- Above: Needed by DataLoader to determine the type of -- Haskell-native join to perform. joinFieldName, joinExtractPath = Nothing } where Ir.AnnObjectSelectG { _aosFields = fields :: Ir.AnnFieldsG 'BigQuery Void Expression, _aosTableFrom = tableFrom :: TableName, _aosTableFilter = tableFilter :: Ir.AnnBoolExp 'BigQuery Expression } = annObjectSelectG Ir.AnnRelationSelectG { _aarRelationshipName, _aarColumnMapping = mapping :: HashMap ColumnName ColumnName, _aarAnnSelect = annObjectSelectG :: Ir.AnnObjectSelectG 'BigQuery Void Expression } = annRelationSelectG -- We're not using existingJoins at the moment, which was used to -- avoid re-joining on the same table twice. _lookupTableFrom :: Map TableName EntityAlias -> TableName -> FromIr (Either EntityAlias From) _lookupTableFrom existingJoins tableFrom = do case M.lookup tableFrom existingJoins of Just entityAlias -> pure (Left entityAlias) Nothing -> fmap Right (fromQualifiedTable tableFrom) fromArraySelectG :: Ir.ArraySelectG 'BigQuery Void Expression -> ReaderT EntityAlias FromIr Join fromArraySelectG = \case Ir.ASSimple arrayRelationSelectG -> fromArrayRelationSelectG arrayRelationSelectG Ir.ASAggregate arrayAggregateSelectG -> fromArrayAggregateSelectG arrayAggregateSelectG -- | Generate a select field @'Expression' for a computed field -- -- > ARRAY( -- > SELECT -- > AS STRUCT -- > `column_1`, -- > `column_2`, -- > `column_3` -- > FROM -- > UNNEST( -- > ARRAY( -- > SELECT AS STRUCT * -- > FROM `dataset`.`function_name`(`argument_name` => `parent_entity`.`column`) -- > ) -- > ) -- > LIMIT 1000 -- global limit -- > ) AS `field_name` -- -- Using 'LIMIT' right after 'FROM ' expression raises query exception. -- To avoid this problem, we are packing and unpacking the rows returned from the function -- using 'ARRAY' and 'UNNEST', then applying LIMIT. Somehow this is working with exact reason -- being unknown. See https://github.com/hasura/graphql-engine/issues/8562 for more details. fromComputedFieldSelect :: Ir.ComputedFieldSelect 'BigQuery Void Expression -> ReaderT EntityAlias FromIr Expression fromComputedFieldSelect = \case Ir.CFSScalar {} -> -- As of now, we don't have support for computed fields returning a scalar value. -- See https://github.com/hasura/graphql-engine/issues/8521 refute $ pure ScalarComputedFieldsNotSupported Ir.CFSTable jsonAggSelect annSimpleSelect -> do entityAlias <- ask select <- lift $ noExtraPartitionFields <$> fromSelectRows (ParentEntityAlias entityAlias) annSimpleSelect let selectWithCardinality = select { selectCardinality = case jsonAggSelect of Rql.JASMultipleRows -> Many Rql.JASSingleObject -> One, selectAsStruct = AsStruct, selectFrom = wrapUnnest (selectFrom select) } pure $ applyArrayOnSelect selectWithCardinality where applyArrayOnSelect :: Select -> Expression applyArrayOnSelect select = FunctionExpression (FunctionName "ARRAY" Nothing) [SelectExpression select] wrapUnnest :: From -> From wrapUnnest from = let starSelect = Select { selectTop = NoTop, selectAsStruct = AsStruct, selectProjections = pure StarProjection, selectFrom = from, selectJoins = [], selectWhere = Where [], selectOrderBy = Nothing, selectOffset = Nothing, selectGroupBy = [], selectFinalWantedFields = Nothing, selectCardinality = Many } arraySelect = applyArrayOnSelect starSelect in FromFunction Aliased { aliasedThing = SelectFromFunction (FunctionName "UNNEST" Nothing) [arraySelect], aliasedAlias = entityAliasText (fromAlias from) } -- | Produce the join for an array aggregate relation. We produce a -- normal select, but then include join fields. Then downstream, the -- DataLoader will execute the lhs select and rhs join in separate -- server queries, then do a Haskell-native join on the join fields. -- -- See also 'fromArrayRelationSelectG' for similar example. fromArrayAggregateSelectG :: Ir.AnnRelationSelectG 'BigQuery (Ir.AnnAggregateSelectG 'BigQuery Void Expression) -> ReaderT EntityAlias FromIr Join fromArrayAggregateSelectG annRelationSelectG = do joinFieldName <- lift (fromRelName _aarRelationshipName) select <- do lhsEntityAlias <- ask lift (fromSelectAggregate (pure (lhsEntityAlias, mapping)) annSelectG) alias <- lift (generateEntityAlias (ArrayAggregateTemplate joinFieldName)) joinOn <- fromMappingFieldNames alias mapping joinFields <- fromMappingFieldNames (fromAlias (selectFrom select)) mapping joinFieldProjections <- toNonEmpty (map prepareJoinFieldProjection joinFields) let projections = selectProjections select <> joinFieldProjections joinSelect = select { selectWhere = selectWhere select, selectGroupBy = map fst joinFields, selectProjections = projections } pure Join { joinAlias = alias, joinSource = JoinSelect joinSelect, joinRightTable = fromAlias (selectFrom select), joinOn, joinProvenance = ArrayAggregateJoinProvenance $ mapMaybe (\p -> (,aggregateProjectionsFieldOrigin p) <$> projectionAlias p) . toList . selectProjections $ select, -- Above: Needed by DataLoader to determine the type of -- Haskell-native join to perform. joinFieldName, joinExtractPath = Nothing } where Ir.AnnRelationSelectG { _aarRelationshipName, _aarColumnMapping = mapping :: HashMap ColumnName ColumnName, _aarAnnSelect = annSelectG } = annRelationSelectG -- | Produce a join for an array relation. -- -- Array relations in PG/MSSQL are expressed using LEFT OUTER JOIN -- LATERAL or OUTER APPLY, which are essentially producing for each -- row on the left an array of the result from the right. Which is -- absolutely what you want for the array relationship. -- -- BigQuery doesn't support that. Therefore we are instead performing -- one big array aggregation, for ALL rows in the table - there is no -- join occurring on the left-hand-side table, grouped by join -- fields. The data-loader will perform the LHS query and the RHS query -- separately. -- -- What we do have is a GROUP BY and make sure that the join fields -- are included in the output. Finally, in the -- DataLoader.Plan/DataLoader.Execute, we implement a Haskell-native -- join of the left-hand-side table and the right-hand-side table. -- -- Data looks like: -- -- join_field_a | join_field_b | aggFieldName (array type) -- 1 | 1 | [ { x: 1, y: 2 }, ... ] -- 1 | 2 | [ { x: 1, y: 2 }, ... ] -- -- etc. -- -- We want to produce a query that looks like: -- -- SELECT artist_other_id, -- For joining. -- -- array_agg(struct(album_self_id, title)) as aggFieldName -- -- -- ^ Aggregating the actual data. -- -- FROM (SELECT *, -- Get everything, plus the row number: -- -- ROW_NUMBER() OVER(PARTITION BY artist_other_id) artist_album_index -- -- FROM hasura.Album -- ORDER BY album_self_id ASC -- -- -- ^ Order by here is important for stable results. Any -- order by clauses for the album should appear here, NOT IN -- THE ARRAY_AGG. -- -- ) -- -- AS indexed_album -- -- WHERE artist_album_index > 1 -- -- ^ Here is where offsetting occurs. -- -- GROUP BY artist_other_id -- -- ^ Group by for joining. -- -- ORDER BY artist_other_id; -- ^ Ordering for the artist table should appear here. -- -- Note: if original select already uses a PARTITION BY internally (for distinct_on) -- join fields are added to partition expressions to give proper semantics of distinct_on -- combined with an array relation fromArrayRelationSelectG :: Ir.ArrayRelationSelectG 'BigQuery Void Expression -> ReaderT EntityAlias FromIr Join fromArrayRelationSelectG annRelationSelectG = do pselect <- (lift . flip fromSelectRows annSelectG . ParentEntityAlias) =<< ask -- Take the original select. joinFieldName <- lift (fromRelName _aarRelationshipName) alias <- lift (generateEntityAlias (ArrayRelationTemplate joinFieldName)) indexAlias <- lift (generateEntityAlias IndexTemplate) joinOn <- fromMappingFieldNames alias mapping joinFields <- fromMappingFieldNames (fromAlias (pselectFrom pselect)) mapping >>= toNonEmpty let select = withExtraPartitionFields pselect $ NE.toList (fmap fst joinFields) joinFieldProjections = fmap prepareJoinFieldProjection joinFields let joinSelect = Select { selectCardinality = One, selectAsStruct = NoAsStruct, selectFinalWantedFields = selectFinalWantedFields select, selectTop = NoTop, selectProjections = joinFieldProjections <> pure ( ArrayAggProjection Aliased { aliasedThing = ArrayAgg { arrayAggProjections = fmap (aliasToFieldProjection (fromAlias (selectFrom select))) (selectProjections select), arrayAggOrderBy = selectOrderBy select, arrayAggTop = selectTop select -- The sub-select takes care of caring about global top. -- -- This handles the LIMIT need. }, aliasedAlias = aggFieldName } ), selectFrom = FromSelect ( Aliased { aliasedAlias = coerce (fromAlias (selectFrom select)), aliasedThing = Select { selectProjections = selectProjections select <> joinFieldProjections `appendToNonEmpty` foldMap @Maybe ( map \OrderBy {orderByFieldName} -> FieldNameProjection Aliased { aliasedThing = orderByFieldName, aliasedAlias = fieldName orderByFieldName } ) (toList <$> selectOrderBy select) -- Above: Select "order by" fields as they're being used -- inside `ARRAY_AGG` function (as ORDER BY clause) <> pure ( WindowProjection ( Aliased { aliasedAlias = unEntityAlias indexAlias, aliasedThing = RowNumberOverPartitionBy -- The row numbers start from 1. ( fmap fst joinFields ) (selectOrderBy select) -- Above: Having the order by -- in here ensures that the -- row numbers are ordered by -- this ordering. Below, we -- order again for the -- general row order. Both -- are needed! } ) ), selectFrom = selectFrom select, selectJoins = selectJoins select, selectWhere = selectWhere select, selectOrderBy = selectOrderBy select, -- Above: This orders the rows themselves. In -- the RowNumberOverPartitionBy, we also set -- a row order for the calculation of the -- indices. Both are needed! selectOffset = Nothing, selectFinalWantedFields = selectFinalWantedFields select, selectCardinality = Many, selectAsStruct = NoAsStruct, selectTop = NoTop, selectGroupBy = mempty } } ), selectWhere = case selectOffset select of Nothing -> mempty Just offset -> Where [ OpExpression MoreOp (ColumnExpression FieldName {fieldNameEntity = coerce (fromAlias (selectFrom select)), fieldName = unEntityAlias indexAlias}) offset ], selectOrderBy = Nothing, -- Not needed. selectJoins = mempty, selectOffset = Nothing, -- This group by corresponds to the field name projections above. E.g. artist_other_id selectGroupBy = map fst (NE.toList joinFields) } pure Join { joinAlias = alias, joinSource = JoinSelect joinSelect, joinRightTable = fromAlias (selectFrom select), joinOn, joinProvenance = ArrayJoinProvenance ( if True then (fromMaybe [] (selectFinalWantedFields select)) else ( mapMaybe projectionAlias (toList (selectProjections select)) ) ), -- Above: Needed by DataLoader to determine the type of -- Haskell-native join to perform. joinFieldName, joinExtractPath = Just aggFieldName } where Ir.AnnRelationSelectG { _aarRelationshipName, _aarColumnMapping = mapping :: HashMap ColumnName ColumnName, _aarAnnSelect = annSelectG } = annRelationSelectG -- | For entity projections, convert any entity aliases to their field -- names. ArrayEntityProjection and ExpressionProjection get converted -- to aliases to fields with the same names as all the expressions -- have already aliases applied in select from ArrayAgg -- (created in Hasura.Backends.BigQuery.ToQuery.fromArrayAgg) aliasToFieldProjection :: EntityAlias -> Projection -> Projection aliasToFieldProjection (EntityAlias selectAlias) = \case EntityProjection Aliased {aliasedAlias = name, aliasedThing = fields} -> EntityProjection Aliased { aliasedAlias = name, aliasedThing = fmap (\(FieldName {..}, origin) -> (FieldName {fieldNameEntity = name, ..}, origin)) fields } ArrayEntityProjection _ aliased -> aliasColumn aliased ExpressionProjection aliased -> aliasColumn aliased p -> p where aliasColumn :: Aliased a -> Projection aliasColumn aliased = ExpressionProjection aliased { aliasedThing = ColumnExpression (FieldName {fieldName = aliasedAlias aliased, fieldNameEntity = selectAlias}) } fromRelName :: Rql.RelName -> FromIr Text fromRelName relName = pure (Rql.relNameToTxt relName) -- | The context given by the reader is of the previous/parent -- "remote" table. The WHERE that we're generating goes in the child, -- "local" query. The @From@ passed in as argument is the local table. -- -- We should hope to see e.g. "post.category = category.id" for a -- local table of post and a remote table of category. -- -- The left/right columns in @HashMap ColumnName ColumnName@ corresponds -- to the left/right of @select ... join ...@. Therefore left=remote, -- right=local in this context. fromMapping :: From -> HashMap ColumnName ColumnName -> ReaderT EntityAlias FromIr [Expression] fromMapping localFrom = traverse ( \(remoteColumn, localColumn) -> do localFieldName <- local (const (fromAlias localFrom)) (fromColumn localColumn) remoteFieldName <- fromColumn remoteColumn pure ( EqualExpression (ColumnExpression localFieldName) (ColumnExpression remoteFieldName) ) ) . HM.toList -- | Given an alias for the remote table, and a map of local-to-remote column -- name pairings, produce 'FieldName' pairings (column names paired with their -- associated table names). -- -- For example, we might convert the following: -- -- @ -- [ ( ColumnName { columnName = "author_id" } -- , ColumnName { columnName = "id" } -- ) -- ] -- @ -- -- ... into something like this: -- -- @ -- ( FieldName -- { fieldName = "id" -- , fieldNameEntity = "t_author1" -- } -- , FieldName -- { fieldName = "author_id" -- , fieldNameEntity = "t_article1" -- } -- ) -- @ -- -- Note that the columns __flip around__ for the output. The input map is -- @(local, remote)@. fromMappingFieldNames :: EntityAlias -> HashMap ColumnName ColumnName -> ReaderT EntityAlias FromIr [(FieldName, FieldName)] fromMappingFieldNames remoteFrom = traverse go . HM.toList where go (localColumn, remoteColumn) = do remoteFieldName <- local (const remoteFrom) (fromColumn remoteColumn) localFieldName <- fromColumn localColumn pure (remoteFieldName, localFieldName) -------------------------------------------------------------------------------- -- Basic SQL expression types fromOpExpG :: Expression -> Ir.OpExpG 'BigQuery Expression -> FromIr Expression fromOpExpG expression op = case op of Ir.ANISNULL -> pure (IsNullExpression expression) Ir.ANISNOTNULL -> pure (IsNotNullExpression expression) Ir.AEQ False val -> pure (nullableBoolEquality expression val) Ir.AEQ True val -> pure (EqualExpression expression val) Ir.ANE False val -> pure (nullableBoolInequality expression val) Ir.ANE True val -> pure (NotEqualExpression expression val) Ir.AIN val -> pure (OpExpression InOp expression val) Ir.ANIN val -> pure (OpExpression NotInOp expression val) Ir.AGT val -> pure (OpExpression MoreOp expression val) Ir.ALT val -> pure (OpExpression LessOp expression val) Ir.AGTE val -> pure (OpExpression MoreOrEqualOp expression val) Ir.ALTE val -> pure (OpExpression LessOrEqualOp expression val) Ir.ACast _casts -> refute (pure (UnsupportedOpExpG op)) Ir.ALIKE val -> pure (OpExpression LikeOp expression val) Ir.ANLIKE val -> pure (OpExpression NotLikeOp expression val) Ir.ABackendSpecific op' -> pure (fromBackendSpecificOpExpG expression op') Ir.CEQ _rhsCol -> refute (pure (UnsupportedOpExpG op)) Ir.CNE _rhsCol -> refute (pure (UnsupportedOpExpG op)) Ir.CGT _rhsCol -> refute (pure (UnsupportedOpExpG op)) Ir.CLT _rhsCol -> refute (pure (UnsupportedOpExpG op)) Ir.CGTE _rhsCol -> refute (pure (UnsupportedOpExpG op)) Ir.CLTE _rhsCol -> refute (pure (UnsupportedOpExpG op)) fromBackendSpecificOpExpG :: Expression -> BigQuery.BooleanOperators Expression -> Expression fromBackendSpecificOpExpG expression op = let func name val = FunctionExpression (FunctionName name Nothing) [expression, val] in case op of BigQuery.ASTContains v -> func "ST_CONTAINS" v BigQuery.ASTEquals v -> func "ST_EQUALS" v BigQuery.ASTTouches v -> func "ST_TOUCHES" v BigQuery.ASTWithin v -> func "ST_WITHIN" v BigQuery.ASTIntersects v -> func "ST_INTERSECTS" v BigQuery.ASTDWithin (Ir.DWithinGeogOp r v sph) -> FunctionExpression (FunctionName "ST_DWITHIN" Nothing) [expression, v, r, sph] nullableBoolEquality :: Expression -> Expression -> Expression nullableBoolEquality x y = OrExpression [ EqualExpression x y, AndExpression [IsNullExpression x, IsNullExpression y] ] nullableBoolInequality :: Expression -> Expression -> Expression nullableBoolInequality x y = OrExpression [ NotEqualExpression x y, AndExpression [IsNotNullExpression x, IsNullExpression y] ] fromGBoolExp :: Ir.GBoolExp 'BigQuery Expression -> ReaderT EntityAlias FromIr Expression fromGBoolExp = \case Ir.BoolAnd expressions -> fmap AndExpression (traverse fromGBoolExp expressions) Ir.BoolOr expressions -> fmap OrExpression (traverse fromGBoolExp expressions) Ir.BoolNot expression -> fmap NotExpression (fromGBoolExp expression) Ir.BoolExists gExists -> fmap ExistsExpression (fromGExists gExists) Ir.BoolField expression -> pure expression -------------------------------------------------------------------------------- -- Misc combinators -- | Attempt to refine a list into a 'NonEmpty'. If the given list is empty, -- this will 'refute' the computation with an 'UnexpectedEmptyList' error. toNonEmpty :: MonadValidate (NonEmpty Error) m => [x] -> m (NonEmpty x) toNonEmpty = \case [] -> refute (UnexpectedEmptyList :| []) x : xs -> pure (x :| xs) -- | Get the remote field from a pair (see 'fromMappingFieldNames' for more -- information) and produce a 'Projection'. prepareJoinFieldProjection :: (FieldName, FieldName) -> Projection prepareJoinFieldProjection (fieldName', _) = FieldNameProjection Aliased { aliasedThing = fieldName', aliasedAlias = fieldName fieldName' } selectProjectionsFromFieldSources :: Bool -> [FieldSource] -> FromIr (NonEmpty Projection) selectProjectionsFromFieldSources keepJoinField fieldSources = do projections <- tolerate do projections' <- traverse (fieldSourceProjections keepJoinField) fieldSources toNonEmpty projections' case projections of Just (x :| xs) -> pure (foldl' (<>) x xs) Nothing -> refute (pure NoProjectionFields) trueExpression :: Expression trueExpression = ValueExpression (BoolValue True) -------------------------------------------------------------------------------- -- Constants aggFieldName :: Text aggFieldName = "agg" existsFieldName :: Text existsFieldName = "exists_placeholder" -------------------------------------------------------------------------------- -- Name generation data NameTemplate = ArrayRelationTemplate Text | ArrayAggregateTemplate Text | ObjectRelationTemplate Text | TableTemplate Text | ForOrderAlias Text | IndexTemplate | UnnestTemplate | FunctionTemplate FunctionName generateEntityAlias :: NameTemplate -> FromIr EntityAlias generateEntityAlias template = do FromIr ( modify' ( \FromIrState {..} -> FromIrState {indices = M.insertWith (+) prefix start indices, ..} ) ) i <- FromIr (gets indices) pure (EntityAlias (prefix <> tshow (fromMaybe start (M.lookup prefix i)))) where start = 1 prefix = T.take 20 rendered rendered = case template of ArrayRelationTemplate sample -> "ar_" <> sample ArrayAggregateTemplate sample -> "aa_" <> sample ObjectRelationTemplate sample -> "or_" <> sample TableTemplate sample -> "t_" <> sample ForOrderAlias sample -> "order_" <> sample IndexTemplate -> "idx" UnnestTemplate -> "unnest" FunctionTemplate FunctionName {..} -> functionName fromAlias :: From -> EntityAlias fromAlias (FromQualifiedTable Aliased {aliasedAlias}) = EntityAlias aliasedAlias fromAlias (FromSelect Aliased {aliasedAlias}) = EntityAlias aliasedAlias fromAlias (FromSelectJson Aliased {aliasedAlias}) = EntityAlias aliasedAlias fromAlias (FromFunction Aliased {aliasedAlias}) = EntityAlias aliasedAlias fieldTextNames :: Ir.AnnFieldsG 'BigQuery Void Expression -> [Text] fieldTextNames = fmap (\(Rql.FieldName name, _) -> name) unEntityAlias :: EntityAlias -> Text unEntityAlias (EntityAlias t) = t -------------------------------------------------------------------------------- -- Global limit support getGlobalTop :: FromIr Top getGlobalTop = FromIr ( asks ( \FromIrReader {config = FromIrConfig {globalSelectLimit}} -> globalSelectLimit ) )