[Plugin: WP-UserOnline] WordPress database error Duplicate entry errors

It seems as though this problem has existed for more than four and a half years:

https://www.ads-software.com/support/topic/plugin-wp-useronline-plugin-28-wp301-broken

And was reported a year ago:

https://www.ads-software.com/support/topic/plugin-wp-useronline-wp-useronline-developing-error-messages

By a few different users:

https://www.ads-software.com/support/topic/plugin-wp-useronline-plugin-28-wp301-broken

…Would be very nice to get this fixed up, as I find myself deleting error_logs virtually every time I ftp into my server ??

I can’t replicate the issue, so patches welcome.

Any information I could provide from my setup that might help? I did delve into the code a bit (obviously it’s coming from core.php, line 155 in v1.81), but was not able to figure out much…

Actually, perhaps this is overly obvious, but is that “Purge table” deletion immediately before the insert clearing previous records for the same user, so the new record can be inserted? If so, wouldn’t the solution just be something like changing:

OR timestamp < DATE_SUB(CURRENT_TIMESTAMP, INTERVAL %d SECOND)

to

OR timestamp <= DATE_SUB(CURRENT_TIMESTAMP, INTERVAL %d SECOND)

so that if there’s already a record of the current user at the SAME moment (or earlier) it’ll be deleted?

…No wait, that wouldn’t be it. But what about just adding a WHERE to the insertion, i.e. something like:

INSERT INTO wp_useronline (blahblah) VALUES (blahblah) WHERE not exists (SELECT * from wp_useronline WHERE user_ip = %s AND timestamp = CURRENT_TIMESTAMP AND user_type = $user_type);

Seems like that should *always* prevent such a duplicate entry, should it not?

Alternatively, ON DUPLICATE KEY UPDATE could be used:

https://dev.mysql.com/doc/refman/5.1/en/insert-on-duplicate.html

If you manage to get a query that no longer produces errors, please let me know.

Honestly, I’ve never worked directly with the database and wouldn’t really be comfortable modifying the queries for fear of breaking the functionality or causing some otherwise unknown side-effect; I was just hoping to provide you some more insight on what maybe causing this (clearly long-standing) issue with your otherwise flawless (as I can tell) plugin ??

I came by all those other error reports just while Googling for a hopeful solution; the WHERE idea came from the first FAQ here: https://www.techonthenet.com/sql/insert.php

I think I may have found at least one cause of the problem:

https://www.ads-software.com/support/topic/plugin-wp-useronline-wordpress-database-error-duplicate-entry-errors-1

Sorry? Was that meant to have a link to a different thread/post? ??

Heh… yeah: https://www.ads-software.com/support/topic/plugin-wp-useronline-ipv6-support

Nice! Expanded it to 39, will let you know if I keep getting those duplicate error logs ??

I’m still getting these errors. I believe it’s happening most often during moments of very high server load, so that likely has something to do with it. In any case, if the insert query itself takes into consideration the possibility of duplicates (as in yours and my proposed solutions above), it should eliminate the risk of this happening once and for all…

It’s been there forever.. To resolve the problem simply use the Mingle Users Online plugin or else the real-time beta feature on Google analytics..

Mingle Users Online is a branch of this plugin and uses the exact same insert query. I don’t see how the bug wouldn’t occur with that plugin but would with this.

Google Analytics wouldn’t able to lookup the actual WordPress user account, just tell you that “someone” is online.

Right, Mingle and the original plugin are the same. But the fact is the original plugin is full of bugs whereas this is not.

Analytics will of course not tell you who is online but otherwise it’s a great resource to know how many people are online and who is reading what..