This is an automated email from the ASF dual-hosted git repository.
jaydoane pushed a commit to branch 3.x
in repository https://gitbox.apache.org/repos/asf/couchdb.git
The following commit(s) were added to refs/heads/3.x by this push:
new 7d0f3db Handle `not_found` lookups removing ddoc cache key
7d0f3db is described below
commit 7d0f3db7930daf9d64e40c2d2195bfa49507a7a6
Author: Jay Doane <[email protected]>
AuthorDate: Thu Dec 9 19:17:19 2021 -0800
Handle `not_found` lookups removing ddoc cache key
For non-existent ddocs, a new ddoc_cache_entry is spawned for each
call to ddoc_cache:open. Multiple calls to open the same non-existent
ddoc will create multiple cache entries with the same Key but
different PIDs. This can result in khash lookups returning `not_found`
as in the error below:
[error] 2021-12-10T02:25:21.622743Z [email protected] <0.18923.9> --------
gen_server ddoc_cache_lru terminated with reason: no match of right hand value
not_found at ddoc_cache_lru:remove_key/2(line:308) <=
ddoc_cache_lru:handle_info/2(line:219) <= gen_server:try_dispatch/4(line:637)
<= gen_server:handle_msg/6(line:711) <= proc_lib:init_p_do_apply/3(line:249)
This checks the return values of `khash:lookup` and only proceeds to
delete keys if the results are other than `not_found`.
---
src/ddoc_cache/src/ddoc_cache_lru.erl | 34 ++++++++++++++++++++++++----------
1 file changed, 24 insertions(+), 10 deletions(-)
diff --git a/src/ddoc_cache/src/ddoc_cache_lru.erl
b/src/ddoc_cache/src/ddoc_cache_lru.erl
index ec8f5ca..7381e6c 100644
--- a/src/ddoc_cache/src/ddoc_cache_lru.erl
+++ b/src/ddoc_cache/src/ddoc_cache_lru.erl
@@ -296,16 +296,30 @@ remove_key(St, Key) ->
} = St,
DbName = ddoc_cache_entry:dbname(Key),
DDocId = ddoc_cache_entry:ddocid(Key),
- {value, DDocIds} = khash:lookup(Dbs, DbName),
- {value, Keys} = khash:lookup(DDocIds, DDocId),
- khash:del(Keys, Key),
- case khash:size(Keys) of
- 0 -> khash:del(DDocIds, DDocId);
- _ -> ok
- end,
- case khash:size(DDocIds) of
- 0 -> khash:del(Dbs, DbName);
- _ -> ok
+
+ % For non-existent ddocs, a new ddoc_cache_entry is spawned for
+ % each call to ddoc_cache:open. Multiple calls to open the same
+ % non-existent ddoc will create multiple cache entries with the
+ % same Key but different PIDs. This can result in the following
+ % khash lookups returning not_found, so handle those corner cases.
+ case khash:lookup(Dbs, DbName) of
+ {value, DDocIds} ->
+ case khash:lookup(DDocIds, DDocId) of
+ {value, Keys} ->
+ ok = khash:del(Keys, Key),
+ case khash:size(Keys) of
+ 0 -> khash:del(DDocIds, DDocId);
+ _ -> ok
+ end,
+ case khash:size(DDocIds) of
+ 0 -> khash:del(Dbs, DbName);
+ _ -> ok
+ end;
+ not_found ->
+ ok
+ end;
+ not_found ->
+ ok
end.
unlink_and_flush(Pid) ->
