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Diffstat (limited to 'lib/dml/executor.ml')
| -rw-r--r-- | lib/dml/executor.ml | 228 |
1 files changed, 0 insertions, 228 deletions
diff --git a/lib/dml/executor.ml b/lib/dml/executor.ml deleted file mode 100644 index f034f4a..0000000 --- a/lib/dml/executor.ml +++ /dev/null @@ -1,228 +0,0 @@ -module Make (NT : Nt.S) = struct - module DrlExec = Drl.Executor.Make (NT) - - module Error = struct - open Condition - - (* TODO: more structure *) - let parse_error msg = condition "parse-error" msg empty - - let relation_not_found name = - condition "relation-not-found" "Relation not found" ("name" |=| of_string name) - - let multigroup_not_found name = - condition "multigroup-not-found" "Multigroup not found" ("name" |=| of_string name) - end - - let ( let* ) = Result.bind - let parse_fqn (s : string) : (Qualified_name.t, Condition.t) result = Qualified_name.try_parse s - - let lookup_mg (ctx : Sublanguage_context.t) (mg_name : string) : - (Management.Multigroup.multigroup, Condition.t) result = - match ctx.branch#mg_of mg_name with - | Some mg -> Ok mg - | None -> Error (Error.multigroup_not_found mg_name) - - let get_rel (ctx : Sublanguage_context.t) (fqn : Qualified_name.t) = - let* mg = lookup_mg ctx fqn.mg in - match NT.get_relation mg fqn.name with - | Some r -> Ok r - | None -> Error (Error.relation_not_found (Qualified_name.to_string fqn)) - - let retarget target (t : Tuple.materialized) = {t with Tuple.relation= target} - - let build_tuple ~relation (attributes : Ast.attr_value list) : Tuple.materialized = - let attr_map = - List.fold_left - (fun acc (name, value) -> - Tuple.AttributeMap.add name {Attribute.value= Drl.Ast.value_to_abstract value} acc ) - Tuple.AttributeMap.empty attributes - in - {Tuple.relation; attributes= attr_map} - - (* Drain all tuples from a DRL query using ctx.resolve for path resolution. - Cross-multigroup reads work transparently here. *) - let drain_query (ctx : Sublanguage_context.t) query = - let* plan = DrlExec.compile ctx query in - let* stream = NT.execute_query plan ~rel_name:"dml_drain" in - let rec drain acc = - match NT.stream_next stream with - | Error _ -> List.rev acc - | Ok None -> List.rev acc - | Ok (Some t) -> drain (t :: acc) - in - let tuples = drain [] in - ignore (NT.stream_close stream); - Ok tuples - - (* Stored-relation paths referenced by a query, for ephemeral dependency - pinning. A qualified leaf resolves through ctx; an unqualified one is a - previously Defined session ephemeral (views compose). *) - let rec base_dep_paths (ctx : Sublanguage_context.t) (q : Drl.Ast.query) : string list = - match q with - | Drl.Ast.Base name -> ( - match Qualified_name.try_parse name with - | Ok fqn -> [ctx.resolve fqn] - | Error _ -> [Sublanguage_context.ephemeral_path ctx name] ) - | Drl.Ast.Const _ -> [] - | Drl.Ast.Select (a, b) - |Drl.Ast.Join (_, a, b) - |Drl.Ast.Cartesian (a, b) - |Drl.Ast.Union (a, b) - |Drl.Ast.Diff (a, b) -> - base_dep_paths ctx a @ base_dep_paths ctx b - | Drl.Ast.Project (_, s) | Drl.Ast.Rename (_, s) | Drl.Ast.Take (_, s) -> base_dep_paths ctx s - - (* Schema of a query result, walked structurally from the base relations' - schemas. Mirrors the operator semantics in docs/relational-algebra.org. *) - let rec infer_schema (ctx : Sublanguage_context.t) (q : Drl.Ast.query) : - (Schema.t, Condition.t) result = - match q with - | Drl.Ast.Base name -> ( - match Qualified_name.try_parse name with - | Error _ -> - (* Session ephemeral: RNT owns its schema; nothing to derive - on the OCaml-side, so treated as contributing no attributes. *) - Ok [] - | Ok fqn -> - let* rel = get_rel ctx fqn in - Ok rel#schema ) - | Drl.Ast.Const attrs -> Ok (List.map (fun (n, _) -> n, "abstract") attrs) - | Drl.Ast.Select (_, src) -> infer_schema ctx src - | Drl.Ast.Join (_, l, r) | Drl.Ast.Cartesian (l, r) -> - let* ls = infer_schema ctx l in - let* rs = infer_schema ctx r in - Ok (ls @ List.filter (fun (n, _) -> not (List.mem_assoc n ls)) rs) - | Drl.Ast.Project (attrs, src) -> - let* s = infer_schema ctx src in - Ok (List.filter (fun (n, _) -> List.mem n attrs) s) - | Drl.Ast.Rename (renames, src) -> - let* s = infer_schema ctx src in - Ok - (List.map - (fun (n, d) -> match List.assoc_opt n renames with Some n' -> n', d | None -> n, d) - s ) - | Drl.Ast.Union (l, _) | Drl.Ast.Diff (l, _) -> infer_schema ctx l - | Drl.Ast.Take (_, src) -> infer_schema ctx src - - let attr_val_eq a b = Stdlib.( = ) a.Attribute.value b.Attribute.value - - let tuple_matches_pred common (target_t : Tuple.materialized) (pred_t : Tuple.materialized) = - List.for_all - (fun attr -> - match - ( Tuple.AttributeMap.find_opt attr target_t.Tuple.attributes, - Tuple.AttributeMap.find_opt attr pred_t.Tuple.attributes ) - with - | Some a, Some b -> attr_val_eq a b - | _ -> false ) - common - - let semijoin common target_tuples pred_tuples = - List.filter (fun t -> List.exists (tuple_matches_pred common t) pred_tuples) target_tuples - - (* DML mutates tuples in a single mg per statement. Returns a - single-element transition delta keyed by that mg's name. *) - let execute (ctx : Sublanguage_context.t) (stmt : Ast.statement) : - (Sublanguage_types.transition_delta, Condition.t) result = - let bh = ctx.write_handle in - let branch_name = ctx.branch#name in - let after fqn = - Result.bind (lookup_mg ctx fqn.Qualified_name.mg) (fun mg -> Ok [fqn.Qualified_name.mg, mg]) - in - match stmt with - | Ast.InsertTuple {relation; attributes} -> - let* fqn = parse_fqn relation in - let* rel = get_rel ctx fqn in - let tuple = build_tuple ~relation:rel#name attributes in - let* _ = NT.create_tuple ~branch_name ~mg_name:fqn.mg ~rel_name:rel#name tuple in - after fqn - | Ast.InsertTuples {relation; tuples} -> - let* fqn = parse_fqn relation in - let* rel = get_rel ctx fqn in - let tuple_list = List.map (build_tuple ~relation:rel#name) tuples in - let* _ = NT.create_tuples ~branch_name ~mg_name:fqn.mg ~rel_name:rel#name tuple_list in - after fqn - | Ast.DeleteTuple {relation; attributes} -> - let* fqn = parse_fqn relation in - let* rel = get_rel ctx fqn in - let tuple = build_tuple ~relation:rel#name attributes in - let hash = Hashing.hash_tuple tuple in - let* () = NT.retract_tuple ~branch_name ~mg_name:fqn.mg ~rel_name:rel#name hash in - after fqn - | Ast.Assign {target; body} -> - let* fqn = parse_fqn target in - let* mg = lookup_mg ctx fqn.mg in - let* rel = get_rel ctx fqn in - let* tuples = drain_query ctx body in - let* _bh, new_mg = - NT.clear_relation bh mg ~branch_name ~mg_name:fqn.mg (rel :> Relation.relation) - in - ctx.branch#set_mg ~name:fqn.mg new_mg; - let* _ = - NT.create_tuples ~branch_name ~mg_name:fqn.mg ~rel_name:rel#name - (List.map (retarget rel#name) tuples) - in - Ok [fqn.mg, new_mg] - | Ast.InsertFrom {target; source} -> - let* fqn = parse_fqn target in - let* rel = get_rel ctx fqn in - let* tuples = drain_query ctx source in - let* _ = - NT.create_tuples ~branch_name ~mg_name:fqn.mg ~rel_name:rel#name - (List.map (retarget rel#name) tuples) - in - after fqn - | Ast.Define {target; body} -> - let* () = - if String.contains target ':' then - Error - (Error.parse_error ("Define target must be unqualified (session-scoped): " ^ target)) - else Ok () - in - (* TODO: redefining an existing name isn't guarded. Right now we lean on - Hashtbl.replace and whatever RNT does on collision. Pick replace or - error and enforce it here. *) - let* schema = infer_schema ctx body in - (* TODO: every page drains the whole query and then filters down to the - window, so paging costs O(total * pages) and reruns the VM plan each - time. Push the offset/limit down or cache the result. *) - let generator ~offset ~limit = - match drain_query ctx body with - | Error _ -> [] - | Ok tuples -> List.filteri (fun i _ -> i >= offset && i < offset + limit) tuples - in - let* _path = - NT.register_ephemeral ~session:ctx.session_hash ~named:true ~name:target ~generator - ~cardinality:Conventions.Cardinality.ConstrainedFinite - ~identity:(Drl.Parser.to_string body) ~schema ~deps:(base_dep_paths ctx body) - in - Ok [] - | Ast.DropDefine {target} -> - let* () = NT.drop_ephemeral ~session:ctx.session_hash ~name:target in - Ok [] - | Ast.DeleteWhere {target; predicate} -> - let* fqn = parse_fqn target in - let* rel = get_rel ctx fqn in - let* target_tuples = drain_query ctx (Drl.Ast.Base target) in - let* pred_tuples = drain_query ctx predicate in - let attr_names_of = function - | [] -> [] - | t :: _ -> List.map fst (Tuple.AttributeMap.bindings t.Tuple.attributes) - in - let target_attrs = attr_names_of target_tuples in - let pred_attrs = attr_names_of pred_tuples in - let common = List.filter (fun n -> List.mem n pred_attrs) target_attrs in - let to_delete = semijoin common target_tuples pred_tuples in - let* () = - List.fold_left - (fun acc t -> - let* () = acc in - let hash = Hashing.hash_tuple (retarget rel#name t) in - NT.retract_tuple ~branch_name ~mg_name:fqn.mg ~rel_name:rel#name hash ) - (Ok ()) to_delete - in - after fqn -end - -module Memory = Make (Nt.Memory) |