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Posted to commits@couchdb.apache.org by va...@apache.org on 2020/02/28 20:26:12 UTC
[couchdb] branch fix-concurrent-db-creation-2613-3.0.x created (now
6f90214)
This is an automated email from the ASF dual-hosted git repository.
vatamane pushed a change to branch fix-concurrent-db-creation-2613-3.0.x
in repository https://gitbox.apache.org/repos/asf/couchdb.git.
at 6f90214 Handle race condition during concurrent db creation
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new 6f90214 Handle race condition during concurrent db creation
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[couchdb] 01/01: Handle race condition during concurrent db creation
Posted by va...@apache.org.
This is an automated email from the ASF dual-hosted git repository.
vatamane pushed a commit to branch fix-concurrent-db-creation-2613-3.0.x
in repository https://gitbox.apache.org/repos/asf/couchdb.git
commit 6f90214a4c38fc9c61d9cfd05f387710d60ac360
Author: Nick Vatamaniuc <va...@apache.org>
AuthorDate: Fri Feb 28 13:30:44 2020 -0500
Handle race condition during concurrent db creation
Previously concurrent db creation requests could get past db_exists/1 and try
to create the shard document. The first one would succeed but the others would
fail with a `500 {"error":"error", "reason":"conflict"}` error instead of
`412`.
Handle the race condition by checking if db exists after getting a conflict
error and return a 412 response.
Fixes: #2613
---
src/fabric/src/fabric_db_create.erl | 6 +++
src/fabric/test/eunit/fabric_db_create_tests.erl | 53 ++++++++++++++++++++++++
2 files changed, 59 insertions(+)
diff --git a/src/fabric/src/fabric_db_create.erl b/src/fabric/src/fabric_db_create.erl
index 03fabb4..1048cb0 100644
--- a/src/fabric/src/fabric_db_create.erl
+++ b/src/fabric/src/fabric_db_create.erl
@@ -37,6 +37,12 @@ go(DbName, Options) ->
case {CreateShardResult, create_shard_db_doc(Doc)} of
{ok, {ok, Status}} ->
Status;
+ {ok, {error, conflict} = ShardDocError} ->
+ % Check if it is just a race to create the shard doc
+ case db_exists(DbName) of
+ true -> {error, file_exists};
+ false -> ShardDocError
+ end;
{file_exists, {ok, _}} ->
{error, file_exists};
{_, Error} ->
diff --git a/src/fabric/test/eunit/fabric_db_create_tests.erl b/src/fabric/test/eunit/fabric_db_create_tests.erl
new file mode 100644
index 0000000..8e5b108
--- /dev/null
+++ b/src/fabric/test/eunit/fabric_db_create_tests.erl
@@ -0,0 +1,53 @@
+% 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(fabric_db_create_tests).
+
+
+-include_lib("couch/include/couch_eunit.hrl").
+-include_lib("couch/include/couch_db.hrl").
+-include_lib("mem3/include/mem3.hrl").
+
+
+-define(TDEF(A), {atom_to_list(A), fun A/0}).
+
+
+main_test_() ->
+ {
+ setup,
+ fun setup/0,
+ fun teardown/1,
+ [
+ ?TDEF(t_handle_shard_doc_conflict)
+ ]
+ }.
+
+
+setup() ->
+ test_util:start_couch([fabric]).
+
+
+teardown(Ctx) ->
+ meck:unload(),
+ test_util:stop_couch(Ctx).
+
+
+t_handle_shard_doc_conflict() ->
+ DbName = ?tempdb(),
+ meck:new(mem3, [passthrough]),
+ meck:new(fabric_util, [passthrough]),
+ ok = meck:sequence(mem3, shards, 1, [
+ fun(_) -> meck:raise(error, database_does_not_exist) end,
+ [#shard{dbname = DbName}]
+ ]),
+ meck:expect(fabric_util, recv, 4, {error, conflict}),
+ ?assertEqual({error, file_exists}, fabric_db_create:go(DbName, [])).