[couchdb] 01/02: optimize _all_docs requests that are bounded within a single partition

[rn...@apache.org]

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

rnewson pushed a commit to branch user-partitioned-dbs-6
in repository https://gitbox.apache.org/repos/asf/couchdb.git

commit b320f78557bbf243ab96f677ee34257732d5a651
Author: Robert Newson <rn...@apache.org>
AuthorDate: Mon Aug 13 22:34:59 2018 +0100

    optimize _all_docs requests that are bounded within a single partition
---
 src/fabric/src/fabric_view_all_docs.erl | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/fabric/src/fabric_view_all_docs.erl b/src/fabric/src/fabric_view_all_docs.erl
index d515ab8..53e689c 100644
--- a/src/fabric/src/fabric_view_all_docs.erl
+++ b/src/fabric/src/fabric_view_all_docs.erl
@@ -21,7 +21,7 @@
 -include_lib("couch_mrview/include/couch_mrview.hrl").
 
 go(DbName, Options, #mrargs{keys=undefined} = QueryArgs, Callback, Acc) ->
-    Shards = mem3:shards(DbName),
+    Shards = shards(DbName, QueryArgs),
     Workers0 = fabric_util:submit_jobs(
             Shards, fabric_rpc, all_docs, [Options, QueryArgs]),
     RexiMon = fabric_util:create_monitors(Workers0),
@@ -136,6 +136,26 @@ go(DbName, _Options, Workers, QueryArgs, Callback, Acc0) ->
         {ok, Resp}
     end.
 
+shards(DbName, Args) ->
+    case couch_mrview_util:get_extra(Args, partitioned) of
+        true ->
+            StartKey = partition(Args#mrargs.start_key),
+            EndKey = partition(Args#mrargs.end_key),
+            case {StartKey, EndKey} of
+                {Same, Same} when Same =/= undefined ->
+                    mem3:shards(DbName, <<Same/binary, ":foo">>);
+                {_, _} ->
+                    mem3:shards(DbName)
+            end;
+        _ ->
+            mem3:shards(DbName)
+    end.
+
+partition(undefined) ->
+    undefined;
+partition(Key) when is_binary(Key) ->
+    hd(binary:split(Key, <<":">>)).
+
 handle_message({rexi_DOWN, _, {_, NodeRef}, _}, _, State) ->
     fabric_view:check_down_shards(State, NodeRef);