[sneaK]

Hey guys, I've been working with a heavily modified timer recently, and I've been trying to work through some crashes. They don't happen immediately (once every hour or so), and generally only happens with lots of clients connected (25+). Can anyone grasp what might be going on based on these accelerator logs?

https://crash.limetech.org/ptyyhkeovnti
https://crash.limetech.org/5uhnsiwg5bwk

No error logs, the best I could find was a brief database connection loss prior to the first crash.

[wwahgnerbp]

did you set timeout in the database config? maybe the engine is making too much queries xD

ps: I'll skip that part of threaded sql queries because you may know already so....

[Neuro Toxin]

The crash reports have stuff after mysql callbacks.

1. Memory leaks?
2. Bad code in a callback

[Peace-Maker]

Are you mixing threaded and non-threaded queries?

[sneaK]

Originally Posted by Peace-Maker Are you mixing threaded and non-threaded queries?

As a matter of fact yes, just did some testing using only threaded queries and the issue seems to be resolved. I'm assuming it's a bad mix?

Thank you guys!

[Peace-Maker]

Just always use threaded queries. There are natives to lock the database connection, so you can make sure no threaded query is executed while you're executing your non-threaded one, but that caused people lots of problems in the past.

[wwahgnerbp]

Originally Posted by Peace-Maker Just always use threaded queries. There are natives to lock the database connection, so you can make sure no threaded query is executed while you're executing your non-threaded one, but that caused people lots of problems in the past.

Would you mind if I ask you why non-threaded queries are so problematic?

[Peace-Maker]

The mysqlclient doesn't like executing two queries at the same time in different threads. If you run a non-threaded query in your plugin you might run it along a threaded query that's been queued. Leading to weird errors or crashes.

You could use the SQL_LockDatabase and SQL_UnlockDatabase natives to avoid that, but if your plugin fails to unlock the database somehow, no further threaded queries will be executed on your database handle.
Not calling UnlockDatabase in early returns or having a script error aborting execution before the unlock call confused script developers, since they often don't know what they're doing when dealing with threads and sourcepawn usually being single threaded.

[asherkin]

Rather than using SQL_LockDatabase and SQL_UnlockDatabase, a much better solution is to open 2 connections (well, the best solution is to only ever use threaded queries - blocking the game thread is bad).