do a non-blocking file:sync --------------------------- Key: COUCHDB-767 URL: https://issues.apache.org/jira/browse/COUCHDB-767 Project: CouchDB Issue Type: Improvement Components: Database Core Affects Versions: 0.11 Reporter: Adam Kocoloski Fix For: 1.1
I've been taking a close look at couch_file performance in our production systems. One of things I've noticed is that reads are occasionally blocked for a long time by a slow call to file:sync. I think this is unnecessary. I think we could do something like handle_call(sync, From, #file{name=Name}=File) -> spawn_link(fun() -> sync_file(Name, From) end), {noreply, File}; and then sync_file(Name, From) -> {ok, Fd} = file:open(Name, [read, raw]), gen_server:reply(From, file:sync(Fd)), file:close(Fd). Does anyone see a downside to this? Individual clients of couch_file still see exactly the same behavior as before, only readers are not blocked by syncs initiated in the db_updater process. When data needs to be flushed file:sync is _much_ slower than spawning a local process and opening the file again -- in the neighborhood of 1000x slower even on Linux with its less-than-durable use of vanilla fsync. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.