Fixed SQL Error When Following User

[digitalpoint]

It's really rare (maybe like once every few days), but I see duplicate entry errors show up in our server log once in awhile when someone tries to follow someone.

Not really sure how to replicate it... I've tried double clicking follow really fast, etc. and I know there's code that checks if they are already following before it tries to follow them, but for whatever reason there's a case where that check fails when it shouldn't somehow.

We aren't using any custom database adapter, no master/slave setup, no custom datawriters or models that would affect it.

Maybe a good idea for it to be an INSERT IGNORE in this case?

 

[Jeremy P]

I get these showing too every once in awhile.

 

[Mike]

It's generally a race condition.

As we're using the datawriter here, it's not trivial to flip to an insert ignore. This isn't something I'd want to do as part of 1.2 as it changes APIs a bit, but it may be an option to choose an insert/update ignore in the DW and detect it in the save (stopping post save/returning false). I think we might need to explicitly opt into it as it could make the insert fail even without any errors after preSave() (unless we then log it as a duplicate record error).

 

[digitalpoint]

The ability for datawriters to support ignore and on duplicate key update is something I've always wished we could do with a flag of some sort. Would be nice to see it in the future...

 

[Jaxel]

Has this ever been added?

 

[ForestForTrees]

Holy crap, this happened to me earlier today.

 

[Chris D]

If it happens, it should be rare and generally won't be a huge issue.

As it stands, this bug is still planned as a "Future Fix".

 

[Mike]

So when using entities (data writers in XF1), you don't really want to use INSERT IGNORE or similar because it doesn't necessarily make it clear how to handle things after the fact. Thus, that isn't something we're likely to do.

However, XF2 does now throw a XF\Db\DuplicateKeyException rather than an XF\Db\Exception for that particular error. This means it can be caught specifically. I've done this for both the follow and ignore cases.

Saying that, XF2 likely partially mitigated this issue before with things in the JS framework which would prevent two requests from normally happening simultaneously.

 

[Dnyan]

Why this is happening post is from 2013.

You are replying now.

 

[Chris D]

This bug was marked as a "Future Fix" back in 2013. It's now the future, and we've now fixed it!