jwdenzel

Bingo! That was it. Web server was using 8.0.19 and the CLI was using 8.1. I updated the CLI to use 8.0 and the maintenance script ran without error. 
Thank you both @Stuart Silvester and @Jim M

Unfortunately, testing this myself, in my own instance, this and a lot of events came over. You may wish to check if there are any timeout errors on your server or other issues.
Additionally, we did make some changes in regards to things for changing the Calendar application over to Events in 4.7.3 so that may also have helped me import this. If you continue to see this issue on 4.7.3, I would advise checking your server for timeouts, errors, etc... If you see anything software related, please let us know.

Hello,
I am working on a new site and since Invision does not support events recurring by X day of the month.  I figured that I would simply do an iCal import for those events.  However, the feed is not bringing in the recurring events at all.  It works perfectly fine for stand alone events, but recurring events are not added to the calendar.

Bingo! That was it. Web server was using 8.0.19 and the CLI was using 8.1. I updated the CLI to use 8.0 and the maintenance script ran without error. 
Thank you both @Stuart Silvester and @Jim M

Bingo! That was it. Web server was using 8.0.19 and the CLI was using 8.1. I updated the CLI to use 8.0 and the maintenance script ran without error. 
Thank you both @Stuart Silvester and @Jim M

Bingo! That was it. Web server was using 8.0.19 and the CLI was using 8.1. I updated the CLI to use 8.0 and the maintenance script ran without error. 
Thank you both @Stuart Silvester and @Jim M

Please ensure that you have all required modules installed on that version of PHP. Currently, you're missing mb_string. Please use the following requirements checker and work with your server administrator to fix anything in red:

https://invisioncommunity.com/files/file/7046-invision-community-requirements-checker/
 

It's possible that you're using a different PHP version/install on command line to the web server. It would be worth checking that /usr/bin/php is the right executable.

If we use Cloudflare that already uses IndexNow, how would behave an IPS IndexNow under layed?

I once used this to fix issue with connection issues to remote MySQL, it's useful in case u have high amount of traffic, you may try this > https://linux.die.net/man/8/tc-sfq

@Thomas P: Thanks for this advice. I'll try it out with redis on the Apache server first and see what happens. 

@jwdenzel I don't have a distributed setup atm, we once had webserver and mysql separately where memcached lived on the webserver.
Currently we use Webserver, MySQL (i.e. MariaDB) and Redis on the same (powerful) machine, which works really great.
If your MySQL has a lot to handle offloading the queries to the webserver using Redis on the Apache host would be effective.
But it depends on your setup and your load during peak times. So my recommendation is: Try both variants and do some measurement on the box to monitor CPU, RAM, Swap and response times etc. when Redis is installed and active on your Apache host for a while (e.g. one week) and on a second try when it is active on your MySQL host in the following week.  
Btw. it is common as well to use Redis on the MySQL host as a front-end database between an application and the MySQL DB.
If you want to offload even more and you don't use it yet: Think about using elasticsearch, it removes a lot of data (i.e. search index) from the MySQL DB and search queries run a lot faster and more accurate.

Do you by any chance have Cloudflare configured for this site, or tried it at one time?
It looks like the frontend does not resolve properly and it actually takes 7 seconds for the server to respond. Once it responds things looks very fast, but there is something going on that locks the request for a while before it can get the server to respond.

 
 

Thanks for this info. I misinterpreted the "Advanced Configurations / Data Caching" page and thought that I could not use Redis with MySQL. But I see that's incorrect. 
I have a dedicated server running MySQL for my website. It's got some good horsepower behind it. Does it makes sense to install Redis on that mysql server? Would I gain any advantage from that even though they are on the same box?
Thanks!

Yes, more than likely - you can use the Theme Differences tool to see all the changes: https://invisioncommunity.com/index.php?app=core&module=system&controller=plugins&do=diff

The upgrade completed, but now I am having a ton of javascript issues.  Most links or functions don't work because it relies on javascript.  The editor doesn't show up, can reply or create new topics. 
I uploaded files manually Ran the support tool, cleared all the caches Cron jobs are running, rebuilt proxies, still working on sitemaps Cleared datastore It is the default theme, i mean right now it couldn't be more default. All the directory permissions seem to be fine, not seeing anything else tell me otherwise. Some admin features don't seem to be working, like the Marketplace, nothing shows up, can't search, so some javascript seems to be off in the admin area as well. Any other ideas on what can be causing so much pain?
I have created a support ticket, but maybe someone here has run into something like this in the past.
I do see errors like this in the console: