> Exclusive Lock -- Do you mean at the application level (quite outside of SQLite3) or are you somehow referring to SQLite3's exclusive locks, which are a different thing entirely? Right sorry, the wording was unclear. All locking is done outside of SQLite. What I meant by exclusive here is that instead of allowing concurrent read requests, I switched to "one request at a time" regardless of their read/write status. > Are you checking every return code for errors? Most but not all, I'll fix that. > Are you using some strange filesystem (any filesystem can be strange, so which one in particular would be helpful). Docker uses overlay, the underlying filesystem is ext4 > Are you using shared_cache or something like that not recommended for use? No > What journal_mode are you using? I don't set any specific mode, so I suppose the default one. > Have you examined whether "docker" supports POSIX advisory locks and sync operations correctly? I must say I haven't. That being said, it seems like SQLite is using docker in the context of OSS-fuzz. > My money would fall on either the application being in error or "docker" being broken. Same here, I'm not saying the issue is on sqlite and wouldn't be surprised if the issue was on my end