Solved Disappearance of Recent Posts on the Forum

A strange incident occurred on two of my independent websites. Around late November to early December, posts from this year disappeared from the forums. More specifically, the forums began displaying posts published before mid-January of this year. To be even more precise, the forum databases somehow "reverted" to their state from mid-January. For example, this is also how the forums are seen by Community Builder.
Unfortunately, I was preoccupied with other matters and did not track the exact date or circumstances that might have caused this.

I would assume that something happened on the server (especially since the hosting provider performed some maintenance during this time), but articles entered during the "missing posts" period are still present on the site.

The last Kunena update to version 6.3.6 was performed on 10 November 2024. The last backup (Akeeba) with the "normal" forum state was made on 25 November 2024.
I am so perplexed about how this could have happened that I am sharing this information primarily to inform Kunena developers and users, not expecting to uncover the exact cause.

However, I do have a practical question: is it possible to restore just the Kunena database fragment from the appropriate backup while ensuring that all of Kunena's connections with the site (Community Builder, Kunena Discuss, etc.) remain intact? For example, would it be sufficient to replace all Kunena-prefixed tables in the database with those from the backup?I am attaching two configuration reports from the smaller of the two websites—one from a backup restored on WAMP server and another from the current server (with the posts missing).

Thanks

  как обстоят дела на форумах 

Did you run diagnostics and recount statistics?

Thank you,
after your question, I did both.
Diagnostics and recount of statistics showed no errors. Everything on the forum remains the same (with lost posts).

There can sometimes be problems with the database, but the fact that this occurs on two different websites cannot be a coincidence. Are these posts still present in the database? Please check it.
Have you or another administrator changed the option in the Kunena menu item ‘Recent Topics’ from ‘Recent topics’ to ‘Newest topic’? If so, it could be that older topics which are still being discussed, have been moved so far back that you can no longer find them. This option lists the topics by creation date and not by topicality.
By the way, the collation of your life site database is utf8mb3, but Joomla and Kunena should have utf8mb4.

rich wrote:

There can sometimes be problems with the database, but the fact that this occurs on two different websites cannot be a coincidence. Are these posts still present in the database? Please check it.
 

Apparently, some of the posts have disappeared. On the website that I gave as an example, the statistics look like this:
After the incident
Total Messages: 2742 Total Sections: 3 Total Subjects: 368 Total Categories: 16
Before the incident
Total Messages: 2914 Total Sections: 3 Total Subjects: 378 Total Categories: 16

rich post=232586 userid=2198Have you or another administrator changed the option in the Kunena menu item ‘Recent Topics’ from ‘Recent topics’ to ‘Newest topic’? If so, it could be that older topics which are still being discussed, have been moved so far back that you can no longer find them. This option lists the topics by creation date and not by topicality.
 

No, no options have changed during my absence.

rich post=232586 userid=2198 

By the way, the collation of your life site database is utf8mb3, but Joomla and Kunena should have utf8mb4.

Thank you for this instruction. I will fix the collation after I restore the forum. But surely this could not affect the disappearance of posts?
(You already pointed out the problems with the collation to me a year or so ago. Then you suggested either fixing it yourself, or waiting for the collation to update when the Kunena is updated. I then chose the second option, and as far as I remember, it worked. Unfortunately, I can't tell you the exact date and check it, since the list of my previous posts /My Topics/ has been reset),  Кстати, да 

However, I do have a practical question: is it possible to restore just the Kunena database fragment from the appropriate backup while ensuring that all of Kunena's connections with the site (Community Builder, Kunena Discuss, etc.) remain intact? For example, would it be sufficient to replace all Kunena-prefixed tables in the database with those from the backup?

Please try this:
1. export all Kunena tables from the backup.
2. export all tables from the Community Builder too.
3. *create a complete backup of your live site.
4. remove the Kunena tables from the Live Page database
4. import all Kunena tables into the live page
5. then synchronise the users in Kunena -> Tools and recount the statistics.
6. synchronise this in the Community Builder as well

If there are differences between CB and Kunena afterwards, you would also have to exchange the Community Builder tables. Then repeat steps 5 and 6.
* If everything goes wrong, you can always fall back on your full backup.

Thank you for this instruction. I will fix the collation after I restore the forum. But surely this could not affect the disappearance of posts?

It is unlikely that posts will disappear due to the incorrect collation. But something must have happened to the database if it was already adapted to utf8mb4. It does not change the collation by itself back. Could it be that an older backup was accidentally restored?

Dear forum administrators!
Your question "Could it be that an older backup was accidentally restored?" put me on the right track.
I corresponded with the hosting support and the situation with the problem of "lost posts" became clear.
Here is their information:

27.11.24 Host Europe Support Team
An operating system update to Debian 12 (Bookworm) was recently rolled out for your server, which also included a minor update for MySQL to 8.0.39. After the maintenance, the MySQL service experienced more frequent downtime, which was caused by individual databases on the server. Unfortunately, attempts to repair the affected databases individually did not yield any lasting improvement. Our specialists conducted extensive research and analyses and implemented the following troubleshooting measures during maintenance.
We downgraded the MySQL version to version 8.0.36 and completely restored all databases on the server to ensure the stability of the databases again. Therefore, current backups of all databases were created in the course of the maintenance and restored after the MySQL version had been downgraded.

Unfortunately, the phrase "completely restored all databases on the server" means that they simply took the old database from the beginning of this year, and did not return the previous database structure, preserving the current data. What is even more terrible is that there was no message about this!

So, there was no loss of posts related to Kunena.

I am very sorry that in a panic I rushed to this forum first and distracted the respected administrators with a question that is not related to them. I sincerely apologize.
This topic should be deleted, of course.

Thank you

No need to apologise, as it is obvious to ask here when Kunena posts have disappeared.
Based on your comment that you had already switched the database to utf8mb4 but the configuration report showed utf8mb3, I surmised that an old backup might have been restored. And you drew the right conclusion from this and asked your hosting provider.
So this discussion has helped to find the cause.