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Posted to commits@couchdb.apache.org by da...@apache.org on 2020/09/24 15:59:20 UTC

[couchdb] 06/07: Use ebtree for reduce functions

This is an automated email from the ASF dual-hosted git repository.

davisp pushed a commit to branch feature-ebtree-views-2
in repository https://gitbox.apache.org/repos/asf/couchdb.git

commit 89c175d97be413815ed5b69c803a92aa9d80c3c5
Author: Paul J. Davis <pa...@gmail.com>
AuthorDate: Wed Jul 29 10:34:48 2020 -0500

    Use ebtree for reduce functions
---
 src/couch_views/src/couch_views.erl        |   6 --
 src/couch_views/src/couch_views_fdb.erl    |   1 -
 src/couch_views/src/couch_views_reader.erl | 153 ++++++++++++++++++++++++++++-
 3 files changed, 150 insertions(+), 10 deletions(-)

diff --git a/src/couch_views/src/couch_views.erl b/src/couch_views/src/couch_views.erl
index da8a142..2d91631 100644
--- a/src/couch_views/src/couch_views.erl
+++ b/src/couch_views/src/couch_views.erl
@@ -161,12 +161,6 @@ maybe_update_view(TxDb, Mrst, false, _Args) ->
     end.
 
 
-is_reduce_view(#mrargs{view_type = ViewType}) ->
-    ViewType =:= red;
-is_reduce_view({Reduce, _, _}) ->
-    Reduce =:= red.
-
-
 to_mrargs(#mrargs{} = Args) ->
     Args;
 
diff --git a/src/couch_views/src/couch_views_fdb.erl b/src/couch_views/src/couch_views_fdb.erl
index 27ef386..fc05af2 100644
--- a/src/couch_views/src/couch_views_fdb.erl
+++ b/src/couch_views/src/couch_views_fdb.erl
@@ -298,7 +298,6 @@ reset_interactive_index(Db, Sig, _St) ->
     {VS, ?INDEX_BUILDING}.
 
 
-
 seq_key(Db, Sig) ->
     #{
         db_prefix := DbPrefix
diff --git a/src/couch_views/src/couch_views_reader.erl b/src/couch_views/src/couch_views_reader.erl
index a785c7b..e2422f7 100644
--- a/src/couch_views/src/couch_views_reader.erl
+++ b/src/couch_views/src/couch_views_reader.erl
@@ -23,7 +23,15 @@
 -include_lib("fabric/include/fabric2.hrl").
 
 
-read(Db, Mrst0, ViewName, UserCallback, UserAcc0, Args) ->
+read(Db, Mrst, ViewName, UserCallback, UserAcc, Args) ->
+    ReadFun = case Args of
+        #mrargs{view_type = map} -> fun read_map_view/6;
+        #mrargs{view_type = red} -> fun read_red_view/6
+    end,
+    ReadFun(Db, Mrst, ViewName, UserCallback, UserAcc, Args).
+
+
+read_map_view(Db, Mrst0, ViewName, UserCallback, UserAcc0, Args) ->
     try
         fabric2_fdb:transactional(Db, fun(TxDb) ->
             #mrst{
@@ -68,6 +76,73 @@ read(Db, Mrst0, ViewName, UserCallback, UserAcc0, Args) ->
     end.
 
 
+read_red_view(Db, Mrst0, ViewName, UserCallback, UserAcc0, Args) ->
+    try
+        fabric2_fdb:transactional(Db, fun(TxDb) ->
+            #mrst{
+                language = Lang,
+                views = Views
+            } = Mrst = couch_views_fdb:set_trees(TxDb, Mrst0),
+
+            #mrargs{
+                extra = Extra
+            } = Args,
+
+            {Idx, Lang, View} = get_red_view(Lang, Args, ViewName, Views),
+            Fun = fun handle_red_row/3,
+
+            Meta = get_red_meta(TxDb, Mrst, View, Args),
+            UserAcc1 = maybe_stop(UserCallback(Meta, UserAcc0)),
+
+            Finalizer = case couch_util:get_value(finalizer, Extra) of
+                undefined ->
+                    {_, FunSrc} = lists:nth(Idx, View#mrview.reduce_funs),
+                    FunSrc;
+                CustomFun->
+                    CustomFun
+            end,
+
+            Acc0 = #{
+                db => TxDb,
+                skip => Args#mrargs.skip,
+                limit => Args#mrargs.limit,
+                mrargs => undefined,
+                finalizer => Finalizer,
+                red_idx => Idx,
+                language => Lang,
+                callback => UserCallback,
+                acc => UserAcc1
+            },
+
+            Acc1 = lists:foldl(fun(KeyArgs, KeyAcc0) ->
+                Opts = mrargs_to_fdb_options(KeyArgs),
+                KeyAcc1 = KeyAcc0#{
+                    mrargs := KeyArgs
+                },
+                couch_views_fdb:fold_red_idx(
+                        TxDb,
+                        View,
+                        Idx,
+                        Opts,
+                        Fun,
+                        KeyAcc1
+                    )
+            end, Acc0, expand_keys_args(Args)),
+
+            #{
+                acc := UserAcc2
+            } = Acc1,
+            {ok, maybe_stop(UserCallback(complete, UserAcc2))}
+        end)
+    catch
+        throw:{complete, Out} ->
+            {_, Final} = UserCallback(complete, Out),
+            {ok, Final};
+        throw:{done, Out} ->
+            {ok, Out}
+    end.
+
+
 get_map_meta(TxDb, Mrst, View, #mrargs{update_seq = true}) ->
     TotalRows = couch_views_trees:get_row_count(TxDb, View),
     ViewSeq = couch_views_fdb:get_update_seq(TxDb, Mrst),
@@ -78,6 +153,14 @@ get_map_meta(TxDb, _Mrst, View, #mrargs{}) ->
     {meta, [{total, TotalRows}, {offset, null}]}.
 
 
+get_red_meta(TxDb, Mrst, _View, #mrargs{update_seq = true}) ->
+    ViewSeq = couch_views_fdb:get_update_seq(TxDb, Mrst),
+    {meta,  [{update_seq, ViewSeq}]};
+
+get_red_meta(_TxDb, _Mrst, _View, #mrargs{}) ->
+    {meta, []}.
+
+
 handle_map_row(_DocId, _Key, _Value, #{skip := Skip} = Acc) when Skip > 0 ->
     Acc#{skip := Skip - 1};
 
@@ -115,6 +198,38 @@ handle_map_row(DocId, Key, Value, Acc) ->
     Acc#{limit := Limit - 1, acc := UserAcc1}.
 
 
+handle_red_row(_Key, _Red, #{skip := Skip} = Acc) when Skip > 0 ->
+    Acc#{skip := Skip - 1};
+
+handle_red_row(_Key, _Value, #{limit := 0, acc := UserAcc}) ->
+    throw({complete, UserAcc});
+
+handle_red_row(Key0, Value0, Acc) ->
+    #{
+        limit := Limit,
+        finalizer := Finalizer,
+        callback := UserCallback,
+        acc := UserAcc0
+    } = Acc,
+
+    Key1 = case Key0 of
+        undefined -> null;
+        _ -> Key0
+    end,
+    Value1 = maybe_finalize(Finalizer, Value0),
+    Row = [{key, Key1}, {value, Value1}],
+
+    UserAcc1 = maybe_stop(UserCallback({row, Row}, UserAcc0)),
+    Acc#{limit := Limit - 1, acc := UserAcc1}.
+
+
+maybe_finalize(null, Red) ->
+    Red;
+maybe_finalize(Finalizer, Red) ->
+    {ok, Finalized} = couch_query_servers:finalize(Finalizer, Red),
+    Finalized.
+
+
 get_map_view(Lang, Args, ViewName, Views) ->
     case couch_mrview_util:extract_view(Lang, Args, ViewName, Views) of
         {map, View, _Args} -> View;
@@ -122,6 +237,13 @@ get_map_view(Lang, Args, ViewName, Views) ->
     end.
 
 
+get_red_view(Lang, Args, ViewName, Views) ->
+    case couch_mrview_util:extract_view(Lang, Args, ViewName, Views) of
+        {red, {Idx, Lang, View}, _} -> {Idx, Lang, View};
+        _ -> throw({not_found, missing_named_view})
+    end.
+
+
 expand_keys_args(#mrargs{keys = undefined} = Args) ->
     [Args];
 
@@ -136,12 +258,14 @@ expand_keys_args(#mrargs{keys = Keys} = Args) ->
 
 mrargs_to_fdb_options(Args) ->
     #mrargs{
+        view_type = ViewType,
         start_key = StartKey,
         start_key_docid = StartKeyDocId,
         end_key = EndKey,
         end_key_docid = EndKeyDocId0,
         direction = Direction,
-        inclusive_end = InclusiveEnd
+        inclusive_end = InclusiveEnd,
+        group_level = GroupLevel
     } = Args,
 
     StartKeyOpts = if StartKey == undefined -> []; true ->
@@ -160,10 +284,33 @@ mrargs_to_fdb_options(Args) ->
         [{end_key, {EndKey, EndKeyDocId}}]
     end,
 
+    GroupFunOpt = make_group_key_fun(ViewType, GroupLevel),
+
     [
         {dir, Direction},
         {inclusive_end, InclusiveEnd}
-    ] ++ StartKeyOpts ++ EndKeyOpts.
+    ] ++ StartKeyOpts ++ EndKeyOpts ++ GroupFunOpt.
+
+
+make_group_key_fun(map, _) ->
+    [];
+
+make_group_key_fun(red, exact) ->
+    [
+        {group_key_fun, fun({Key, _DocId}) -> Key end}
+    ];
+
+make_group_key_fun(red, 0) ->
+    [
+        {group_key_fun, group_all}
+    ];
+
+make_group_key_fun(red, N) when is_integer(N), N > 0 ->
+    GKFun = fun
+        ({Key, _DocId}) when is_list(Key) -> lists:sublist(Key, N);
+        ({Key, _DocId}) -> Key
+    end,
+    [{group_key_fun, GKFun}].
 
 
 maybe_stop({ok, Acc}) -> Acc;