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Posted to commits@couchdb.apache.org by ra...@apache.org on 2011/12/16 02:00:29 UTC
[2/3] git commit: Fix COUCHDB-1363 - race condition in couch_changes
Fix COUCHDB-1363 - race condition in couch_changes
It's necessary to re-open the #db after subscribing to notifications
so that updates are not lost. In practice, this is rarely problematic
because the next change will cause everything to catch up, but if a
quick burst of changes happens while replication is starting the
replication can go stale. Detected by intermittent replicator_db js
test failures.
Project: http://git-wip-us.apache.org/repos/asf/couchdb/repo
Commit: http://git-wip-us.apache.org/repos/asf/couchdb/commit/6a04e333
Tree: http://git-wip-us.apache.org/repos/asf/couchdb/tree/6a04e333
Diff: http://git-wip-us.apache.org/repos/asf/couchdb/diff/6a04e333
Branch: refs/heads/1.1.x
Commit: 6a04e333663596aba4a4d8889e63459b95ef99ff
Parents: c9b20f2
Author: Randall Leeds <ra...@apache.org>
Authored: Wed Dec 14 20:12:08 2011 -0800
Committer: Randall Leeds <ra...@apache.org>
Committed: Thu Dec 15 16:53:28 2011 -0800
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src/couchdb/couch_changes.erl | 18 ++++++++++++------
1 files changed, 12 insertions(+), 6 deletions(-)
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http://git-wip-us.apache.org/repos/asf/couchdb/blob/6a04e333/src/couchdb/couch_changes.erl
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diff --git a/src/couchdb/couch_changes.erl b/src/couchdb/couch_changes.erl
index 2be3779..b89f4d2 100644
--- a/src/couchdb/couch_changes.erl
+++ b/src/couchdb/couch_changes.erl
@@ -20,23 +20,28 @@ handle_changes(#changes_args{style=Style}=Args1, Req, Db) ->
#changes_args{feed = Feed} = Args = Args1#changes_args{
filter = make_filter_fun(Args1#changes_args.filter, Style, Req, Db)
},
- StartSeq = case Args#changes_args.dir of
- rev ->
- couch_db:get_update_seq(Db);
- fwd ->
- Args#changes_args.since
+ Start = fun() ->
+ {ok, Db} = couch_db:reopen(Db0),
+ StartSeq = case Dir of
+ rev ->
+ couch_db:get_update_seq(Db);
+ fwd ->
+ Since
+ end,
+ {Db, StartSeq}
end,
if Feed == "continuous" orelse Feed == "longpoll" ->
fun(CallbackAcc) ->
{Callback, UserAcc} = get_callback_acc(CallbackAcc),
Self = self(),
{ok, Notify} = couch_db_update_notifier:start_link(
- fun({_, DbName}) when DbName == Db#db.name ->
+ fun({_, DbName}) when Db0#db.name == DbName ->
Self ! db_updated;
(_) ->
ok
end
),
+ {Db, StartSeq} = Start(),
UserAcc2 = start_sending_changes(Callback, UserAcc, Feed),
{Timeout, TimeoutFun} = get_changes_timeout(Args, Callback),
try
@@ -58,6 +63,7 @@ handle_changes(#changes_args{style=Style}=Args1, Req, Db) ->
true ->
fun(CallbackAcc) ->
{Callback, UserAcc} = get_callback_acc(CallbackAcc),
+ {Db, StartSeq} = Start(),
UserAcc2 = start_sending_changes(Callback, UserAcc, Feed),
{ok, {_, LastSeq, _Prepend, _, _, UserAcc3, _, _, _, _}} =
send_changes(