From 1074767a6b2a254fc6abcb08ec8ccc156e5aa6e9 Mon Sep 17 00:00:00 2001
From: Filipe David Borba Manana <fdmanana@apache.org>
Date: Fri, 19 Nov 2010 01:38:41 +0000
Subject: Make sure that after a local database compaction the old database
 reference counters don't get unreleased forever because of a continuous (or
 long) replication is going on.

Same type of issue as in COUCHDB-926.
Thanks Adam Kocoloski for some suggestions.



git-svn-id: https://svn.apache.org/repos/asf/couchdb/trunk@1036705 13f79535-47bb-0310-9956-ffa450edef68
---
 src/couchdb/couch_rep.erl | 74 +++++++++++++++++++++++++++++++++++++----------
 1 file changed, 59 insertions(+), 15 deletions(-)

(limited to 'src/couchdb/couch_rep.erl')

diff --git a/src/couchdb/couch_rep.erl b/src/couchdb/couch_rep.erl
index e288efa6..b5918abc 100644
--- a/src/couchdb/couch_rep.erl
+++ b/src/couchdb/couch_rep.erl
@@ -53,7 +53,9 @@
     committed_seq = 0,
 
     stats = nil,
-    rep_doc = nil
+    rep_doc = nil,
+    source_db_update_notifier = nil,
+    target_db_update_notifier = nil
 }).
 
 %% convenience function to do a simple replication from the shell
@@ -187,7 +189,9 @@ do_init([RepId, {PostProps} = RepDoc, UserCtx] = InitArgs) ->
         rep_starttime = httpd_util:rfc1123_date(),
         src_starttime = couch_util:get_value(instance_start_time, SourceInfo),
         tgt_starttime = couch_util:get_value(instance_start_time, TargetInfo),
-        rep_doc = RepDoc
+        rep_doc = RepDoc,
+        source_db_update_notifier = source_db_update_notifier(Source),
+        target_db_update_notifier = target_db_update_notifier(Target)
     },
     {ok, State}.
 
@@ -195,7 +199,21 @@ handle_call(get_result, From, #state{complete=true, listeners=[]} = State) ->
     {stop, normal, State#state{listeners=[From]}};
 handle_call(get_result, From, State) ->
     Listeners = State#state.listeners,
-    {noreply, State#state{listeners=[From|Listeners]}}.
+    {noreply, State#state{listeners=[From|Listeners]}};
+
+handle_call(get_source_db, _From, #state{source = Source} = State) ->
+    {reply, {ok, Source}, State};
+
+handle_call(get_target_db, _From, #state{target = Target} = State) ->
+    {reply, {ok, Target}, State}.
+
+handle_cast(reopen_source_db, #state{source = Source} = State) ->
+    {ok, NewSource} = couch_db:reopen(Source),
+    {noreply, State#state{source = NewSource}};
+
+handle_cast(reopen_target_db, #state{target = Target} = State) ->
+    {ok, NewTarget} = couch_db:reopen(Target),
+    {noreply, State#state{target = NewTarget}};
 
 handle_cast(do_checkpoint, State) ->
     {noreply, do_checkpoint(State)};
@@ -255,11 +273,11 @@ terminate(normal, State) ->
 terminate(shutdown, #state{listeners = Listeners} = State) ->
     % continuous replication stopped
     [gen_server:reply(L, {ok, stopped}) || L <- Listeners],
-    do_forced_terminate(State);
+    terminate_cleanup(State);
 
 terminate(Reason, #state{listeners = Listeners} = State) ->
     [gen_server:reply(L, {error, Reason}) || L <- Listeners],
-    do_forced_terminate(State),
+    terminate_cleanup(State),
     update_rep_doc(State#state.rep_doc, [{<<"state">>, <<"error">>}]).
 
 code_change(_OldVsn, State, _Extra) ->
@@ -267,11 +285,6 @@ code_change(_OldVsn, State, _Extra) ->
 
 % internal funs
 
-do_forced_terminate(#state{source = Source, target = Target, stats = Stats}) ->
-    ets:delete(Stats),
-    close_db(Target),
-    close_db(Source).
-
 start_replication_server(Replicator) ->
     RepId = element(1, Replicator),
     case supervisor:start_child(couch_rep_sup, Replicator) of
@@ -399,13 +412,20 @@ do_terminate(State) ->
         false ->
             [gen_server:reply(R, retry) || R <- OtherListeners]
     end,
+    couch_task_status:update("Finishing"),
     terminate_cleanup(State).
 
-terminate_cleanup(#state{source=Source, target=Target, stats=Stats}) ->
-    couch_task_status:update("Finishing"),
-    close_db(Target),
-    close_db(Source),
-    ets:delete(Stats).
+terminate_cleanup(State) ->
+    close_db(State#state.source),
+    close_db(State#state.target),
+    stop_db_update_notifier(State#state.source_db_update_notifier),
+    stop_db_update_notifier(State#state.target_db_update_notifier),
+    ets:delete(State#state.stats).
+
+stop_db_update_notifier(nil) ->
+    ok;
+stop_db_update_notifier(Notifier) ->
+    couch_db_update_notifier:stop(Notifier).
 
 has_session_id(_SessionId, []) ->
     false;
@@ -887,3 +907,27 @@ ensure_rep_ddoc_exists(RepDb, DDocID) ->
         {ok, _Rev} = couch_db:update_doc(RepDb, DDoc, [])
     end,
     ok.
+
+source_db_update_notifier(#db{name = DbName}) ->
+    Server = self(),
+    {ok, Notifier} = couch_db_update_notifier:start_link(
+        fun({compacted, DbName1}) when DbName1 =:= DbName ->
+                ok = gen_server:cast(Server, reopen_source_db);
+            (_) ->
+                ok
+        end),
+    Notifier;
+source_db_update_notifier(_) ->
+    nil.
+
+target_db_update_notifier(#db{name = DbName}) ->
+    Server = self(),
+    {ok, Notifier} = couch_db_update_notifier:start_link(
+        fun({compacted, DbName1}) when DbName1 =:= DbName ->
+                ok = gen_server:cast(Server, reopen_target_db);
+            (_) ->
+                ok
+        end),
+    Notifier;
+target_db_update_notifier(_) ->
+    nil.
-- 
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