I did find this issue: https://github.com/joomla/joomla-cms/issues/8189 re the JTable reorder function and old issue 

Here is a breakdown of the slowest elements from submitting our form. 39% delay is our SMTP email send.

Slowest components Count Duration %

JTable::reorder 1 26,600 ms 49%

SMTP::get_lines 12 20,800 ms 39%

MySQL j321_content update 856 5,180 ms 10%

MySQL j321_content select 2 401 ms 1%

JDatabaseDriverMysqli::execute 950 264 ms 0%

SMTP::connect 2 190 ms 0%

Remainder 1 506 ms 1%

Total time 53,900 ms 100% 

Hi,

glad you found out the cause of your problem, by testing solution linked at github you can help yourself, they need 2 good test to be able to merge the patch to next joomla version. For the slow email submit you will need to contact your host.

There is a patch but it does not seem make a bit of difference, but the SMTP connection is still a problem. Seblod should still be OK adding records to a database with 12,000 articles -- true?

No one else has encountered this ? Apparently it's been a problem since Joomla 3.4.5 -- see: https://issues.joomla.org/tracker/joomla-cms/8189

This sounds like a huge problem for Joomla whenever the number of articles exceeds XXX (not sure 1000, maybe) per these links:

https://github.com/joomla/joomla-cms/pull/8563

https://github.com/joomla/joomla-cms/pull/8576 <-- this has a debugging info

Are Seblod moderators aware of this??

This sounds like an IMPORTANT ARGUMENT NOT TO USE JOOMLA, if you are expecting 1000s of form submissions.

@cubist, don't take your case for a generality! So please stop now!

Currently YOU meet an issue and I see no other case. Before to cry about Joomla regarding your own personal case please be serious and check a lot more! Always easy to believe to find an issue always lot more difficult to find a real one and to prove it!

It was happening on our shared server before as well. I mentioned VDS to see if there are particular settings we can tweak. WE have 13000 ids and counting. Should archiving help?

I am testing things on the sister site without SMTP (using PHP mailer instead) and it appears Seblod and Joomla are delayed in creating the email to go out. 

1000 articles is nothing, there might be things running a bit slower when we talk about million items or so, but any hosting should be able to handle 1000 articles on joomla. So if I would you I would start at the first line of your first post:

"We recently switched a VDS server".

Only conclusion without having access to the server is that your hoster obviously has slow mysql servers or slow SMTP server "39% delay is our SMTP email send." should tell you everything, no patch can solve this.

It was happening on our shared server before as well. I mentioned VDS to see if there are particular settings we can tweak. WE have 13000 ids and counting. Should archiving help?

I am testing things on the sister site without SMTP (using PHP mailer instead) and it appears Seblod and Joomla are delayed in creating the email to go out. 

SOLUTION

Our site's content type includes 5 Group X forms. It appears on our case, that Seblod had some sorting issues when preparing and building the outgoing email. Our website accrued some 13000+ of these forms to date. This did clog the system when building the email confirmations.

Rather than actually use Joomla's article archive function, we created an Archived category and moved all Joomla associated articles dated prior to Jan 1, 2016 into the Archived category. This did expedite the time to send an email greatly; from 25+ seconds to 5 seconds or less. This should probably be done every month and would be even faster.

Also, note worthy … Although Joomla articles table does hold the Group X data linked to the CCK form. This solution does NOT preclude searching and viewing ALL of our forms to date from the general searches by admin staff or by users who search their previous submissions. Thus, the form search works fine across current and archived categories during one search.