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| author | Gerhard Lazu <gerhard@lazu.co.uk> | 2018-02-22 14:25:37 +0000 |
|---|---|---|
| committer | Gerhard Lazu <gerhard@lazu.co.uk> | 2018-03-27 16:07:35 +0100 |
| commit | 0752ddb4dc5f78673605616a038057616c08cc6c (patch) | |
| tree | f76bbf72d33e9b32c628c7493934abffb2e2393f | |
| parent | 5f7b7cd66b9c0274e7b0b52494f320da7b5798fb (diff) | |
| download | rabbitmq-server-git-0752ddb4dc5f78673605616a038057616c08cc6c.tar.gz | |
Delete bindings from mnesia without full table scan
mnesia:match_object/3 scans the entire table and can take many seconds
on a loaded node. This is especially bad when there are many bindings
which need to be deleted. If the object is in the table then delete it,
otherwise carry on.
Prior to this change, it was observed that there is a high % of
lock collisions in rabbit_topic_trie_binding table:
```
lock id #tries #collisions collisions [%] time [us] duration [%] histogram [log2(us)]
----- --- ------- ------------ --------------- ---------- ------------- ---------------------
db_tab rabbit_topic_trie_binding 258465 13627 5.2723 1389904 0.0370 | ...XXxxXx.......... |
```
mnesia:match_object/3 uses a table index if it exists, but in the case
of rabbit_topic_trie_binding, there is no table index, so a full table
scan used to be performed.
For more context, see #1513
Partner-in-crime: @essen
| -rw-r--r-- | src/rabbit_binding.erl | 9 |
1 files changed, 2 insertions, 7 deletions
diff --git a/src/rabbit_binding.erl b/src/rabbit_binding.erl index e4d9e64d6b..7498d6b765 100644 --- a/src/rabbit_binding.erl +++ b/src/rabbit_binding.erl @@ -331,13 +331,8 @@ binding_action(Binding = #binding{source = SrcName, Fun(Src, Dst, Binding#binding{args = SortedArgs}) end, ErrFun). -delete_object(Tab, Record, LockKind) -> - %% this 'guarded' delete prevents unnecessary writes to the mnesia - %% disk log - case mnesia:match_object(Tab, Record, LockKind) of - [] -> ok; - [_] -> mnesia:delete_object(Tab, Record, LockKind) - end. +delete_object(Table, Record, LockKind) -> + mnesia:delete_object(Table, Record, LockKind). sync_route(Route, true, true, Fun) -> ok = Fun(rabbit_durable_route, Route, write), |