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% Licensed under the Apache License, Version 2.0 (the "License"); you may not
% use this file except in compliance with the License. You may obtain a copy of
% the License at
%
% http://www.apache.org/licenses/LICENSE-2.0
%
% Unless required by applicable law or agreed to in writing, software
% distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
% WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
% License for the specific language governing permissions and limitations under
% the License.
-module(couch_view_updater).
-export([update/1]).
-include("couch_db.hrl").
update(#group{db=#db{name=DbName}=Db,name=GroupName,current_seq=Seq,purge_seq=PurgeSeq}=Group) ->
couch_task_status:add_task(<<"View Group Indexer">>, <<DbName/binary," ",GroupName/binary>>, <<"Starting index update">>),
DbPurgeSeq = couch_db:get_purge_seq(Db),
Group2 =
if DbPurgeSeq == PurgeSeq ->
Group;
DbPurgeSeq == PurgeSeq + 1 ->
couch_task_status:update(<<"Removing purged entries from view index.">>),
purge_index(Group);
true ->
couch_task_status:update(<<"Resetting view index due to lost purge entries.">>),
exit(reset)
end,
ViewEmptyKVs = [{View, []} || View <- Group2#group.views],
% compute on all docs modified since we last computed.
TotalChanges = couch_db:count_changes_since(Db, Seq),
% update status every half second
couch_task_status:set_update_frequency(500),
{ok, {_,{UncomputedDocs, Group3, ViewKVsToAdd, DocIdViewIdKeys}}}
= couch_db:enum_docs_since(
Db,
Seq,
fun(DocInfo, _, {ChangesProcessed, Acc}) ->
couch_task_status:update("Processed ~p of ~p changes (~p%)",
[ChangesProcessed, TotalChanges, (ChangesProcessed*100) div TotalChanges]),
{ok, {ChangesProcessed+1, process_doc(Db, DocInfo, Acc)}}
end,
{0, {[], Group2, ViewEmptyKVs, []}}
),
couch_task_status:set_update_frequency(0),
couch_task_status:update("Finishing."),
{Group4, Results} = view_compute(Group3, UncomputedDocs),
{ViewKVsToAdd2, DocIdViewIdKeys2} = view_insert_query_results(
UncomputedDocs, Results, ViewKVsToAdd, DocIdViewIdKeys),
couch_query_servers:stop_doc_map(Group4#group.query_server),
NewSeq = couch_db:get_update_seq(Db),
{ok, Group5} = write_changes(Group4, ViewKVsToAdd2, DocIdViewIdKeys2,
NewSeq),
exit({new_group, Group5#group{query_server=nil}}).
purge_index(#group{db=Db, views=Views, id_btree=IdBtree}=Group) ->
{ok, PurgedIdsRevs} = couch_db:get_last_purged(Db),
Ids = [Id || {Id, _Revs} <- PurgedIdsRevs],
{ok, Lookups, IdBtree2} = couch_btree:query_modify(IdBtree, Ids, [], Ids),
% now populate the dictionary with all the keys to delete
ViewKeysToRemoveDict = lists:foldl(
fun({ok,{DocId,ViewNumRowKeys}}, ViewDictAcc) ->
lists:foldl(
fun({ViewNum, RowKey}, ViewDictAcc2) ->
dict:append(ViewNum, {RowKey, DocId}, ViewDictAcc2)
end, ViewDictAcc, ViewNumRowKeys);
({not_found, _}, ViewDictAcc) ->
ViewDictAcc
end, dict:new(), Lookups),
% Now remove the values from the btrees
Views2 = lists:map(
fun(#view{id_num=Num,btree=Btree}=View) ->
case dict:find(Num, ViewKeysToRemoveDict) of
{ok, RemoveKeys} ->
{ok, Btree2} = couch_btree:add_remove(Btree, [], RemoveKeys),
View#view{btree=Btree2};
error -> % no keys to remove in this view
View
end
end, Views),
Group#group{id_btree=IdBtree2,
views=Views2,
purge_seq=couch_db:get_purge_seq(Db)}.
process_doc(Db, DocInfo, {Docs, #group{sig=Sig,name=GroupId}=Group, ViewKVs,
DocIdViewIdKeys}) ->
% This fun computes once for each document
#doc_info{id=DocId, deleted=Deleted} = DocInfo,
case DocId of
GroupId ->
% uh oh. this is the design doc with our definitions. See if
% anything in the definition changed.
case couch_db:open_doc(Db, DocInfo) of
{ok, Doc} ->
case couch_view_group:design_doc_to_view_group(Doc) of
#group{sig=Sig} ->
% The same md5 signature, keep on computing
{Docs, Group, ViewKVs, DocIdViewIdKeys};
_ ->
exit(reset)
end;
{not_found, deleted} ->
exit(reset)
end;
<<?DESIGN_DOC_PREFIX, _/binary>> -> % we skip design docs
{Docs, Group, ViewKVs, DocIdViewIdKeys};
_ ->
{Docs2, DocIdViewIdKeys2} =
if Deleted ->
{Docs, [{DocId, []} | DocIdViewIdKeys]};
true ->
{ok, Doc} = couch_db:open_doc(Db, DocInfo, [conflicts, deleted_conflicts]),
{[Doc | Docs], DocIdViewIdKeys}
end,
case couch_util:should_flush() of
true ->
{Group1, Results} = view_compute(Group, Docs2),
{ViewKVs3, DocIdViewIdKeys3} = view_insert_query_results(Docs2, Results, ViewKVs, DocIdViewIdKeys2),
{ok, Group2} = write_changes(Group1, ViewKVs3, DocIdViewIdKeys3,
DocInfo#doc_info.update_seq),
garbage_collect(),
ViewEmptyKeyValues = [{View, []} || View <- Group2#group.views],
{[], Group2, ViewEmptyKeyValues, []};
false ->
{Docs2, Group, ViewKVs, DocIdViewIdKeys2}
end
end.
view_insert_query_results([], [], ViewKVs, DocIdViewIdKeysAcc) ->
{ViewKVs, DocIdViewIdKeysAcc};
view_insert_query_results([Doc|RestDocs], [QueryResults | RestResults], ViewKVs, DocIdViewIdKeysAcc) ->
{NewViewKVs, NewViewIdKeys} = view_insert_doc_query_results(Doc, QueryResults, ViewKVs, [], []),
NewDocIdViewIdKeys = [{Doc#doc.id, NewViewIdKeys} | DocIdViewIdKeysAcc],
view_insert_query_results(RestDocs, RestResults, NewViewKVs, NewDocIdViewIdKeys).
view_insert_doc_query_results(_Doc, [], [], ViewKVsAcc, ViewIdKeysAcc) ->
{lists:reverse(ViewKVsAcc), lists:reverse(ViewIdKeysAcc)};
view_insert_doc_query_results(#doc{id=DocId}=Doc, [ResultKVs|RestResults], [{View, KVs}|RestViewKVs], ViewKVsAcc, ViewIdKeysAcc) ->
% Take any identical keys and combine the values
ResultKVs2 = lists:foldl(
fun({Key,Value}, [{PrevKey,PrevVal}|AccRest]) ->
case Key == PrevKey of
true ->
case PrevVal of
{dups, Dups} ->
[{PrevKey, {dups, [Value|Dups]}} | AccRest];
_ ->
[{PrevKey, {dups, [Value,PrevVal]}} | AccRest]
end;
false ->
[{Key,Value},{PrevKey,PrevVal}|AccRest]
end;
(KV, []) ->
[KV]
end, [], lists:sort(ResultKVs)),
NewKVs = [{{Key, DocId}, Value} || {Key, Value} <- ResultKVs2],
NewViewKVsAcc = [{View, NewKVs ++ KVs} | ViewKVsAcc],
NewViewIdKeys = [{View#view.id_num, Key} || {Key, _Value} <- ResultKVs2],
NewViewIdKeysAcc = NewViewIdKeys ++ ViewIdKeysAcc,
view_insert_doc_query_results(Doc, RestResults, RestViewKVs, NewViewKVsAcc, NewViewIdKeysAcc).
view_compute(Group, []) ->
{Group, []};
view_compute(#group{def_lang=DefLang, query_server=QueryServerIn}=Group, Docs) ->
{ok, QueryServer} =
case QueryServerIn of
nil -> % doc map not started
Definitions = [View#view.def || View <- Group#group.views],
couch_query_servers:start_doc_map(DefLang, Definitions);
_ ->
{ok, QueryServerIn}
end,
{ok, Results} = couch_query_servers:map_docs(QueryServer, Docs),
{Group#group{query_server=QueryServer}, Results}.
write_changes(Group, ViewKeyValuesToAdd, DocIdViewIdKeys, NewSeq) ->
#group{id_btree=IdBtree} = Group,
AddDocIdViewIdKeys = [{DocId, ViewIdKeys} || {DocId, ViewIdKeys} <- DocIdViewIdKeys, ViewIdKeys /= []],
RemoveDocIds = [DocId || {DocId, ViewIdKeys} <- DocIdViewIdKeys, ViewIdKeys == []],
LookupDocIds = [DocId || {DocId, _ViewIdKeys} <- DocIdViewIdKeys],
{ok, LookupResults, IdBtree2}
= couch_btree:query_modify(IdBtree, LookupDocIds, AddDocIdViewIdKeys, RemoveDocIds),
KeysToRemoveByView = lists:foldl(
fun(LookupResult, KeysToRemoveByViewAcc) ->
case LookupResult of
{ok, {DocId, ViewIdKeys}} ->
lists:foldl(
fun({ViewId, Key}, KeysToRemoveByViewAcc2) ->
dict:append(ViewId, {Key, DocId}, KeysToRemoveByViewAcc2)
end,
KeysToRemoveByViewAcc, ViewIdKeys);
{not_found, _} ->
KeysToRemoveByViewAcc
end
end,
dict:new(), LookupResults),
Views2 = [
begin
KeysToRemove = couch_util:dict_find(View#view.id_num, KeysToRemoveByView, []),
{ok, ViewBtree2} = couch_btree:add_remove(View#view.btree, AddKeyValues, KeysToRemove),
View#view{btree = ViewBtree2}
end
||
{View, AddKeyValues} <- ViewKeyValuesToAdd
],
Group2 = Group#group{views=Views2, current_seq=NewSeq, id_btree=IdBtree2},
{ok, Group2}.
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