Craft CMS: Data too long for column 'cacheKey' at row 1 We have Craft CMS v3 using multi-sites.
We are using cache to cache whole pages based on the absolute URL as some URLs have query parameters which seem to be ignored when not using a key.  So the absoluteUrl is working. Our cache code is:
{% cache using key craft.app.request.absoluteUrl unless craft.app.request.getSegment(1) == 'members' or craft.app.request.getSegment(1) == 'data-summary' %}

One of the sites, Korean, has a few pages that result in an Internal Server Error as follows.
Next Twig\Error\RuntimeError: An exception has been thrown during the rendering of a template (&quot;SQLSTATE[22001]: String data, right truncated: 1406 Data too long for column 'cacheKey' at row 1

This leads me to believe the URL is longer than 255 characters as the database column templatecaches.cacheKey is varchar(255).
The SQL is:
The SQL being executed was: INSERT INTO `templatecaches` (`cacheKey`, `siteId`, `path`, `expiryDate`, `body`) VALUES ('https://www.mydomain.com/ko/%C3%AC%C2%86%C2%8C%C3%AA%C2%B0%C2%9C/%C3%AC%C2%9D%C2%B8%C3%AC%C2%A6%C2%9D-%C3%AB%C2%B0%C2%8F-%C3%AC%C2%88%C2%98%C3%AC%C2%83%C2%81-%C3%AB%C2%82%C2%B4%C3%AC%C2%97%C2%AD/%C3%AC%C2%B5%C2%9C%C3%AA%C2%B3%C2%A0-%C3%AA%C2%B8%C2%B0%C3%AC%C2%97%C2%85-%C3%AC%C2%88%C2%98%C3%AC%C2%83%C2%81?__geom=%E2%9C%AA', 26, 'site:ìê°/ì¸ì¦-ë°-ìì-ë´ì­/ìµê³ -ê¸°ì-ìì', '2020-11-16 18:41:26', '[all the page content here]')&quot;). in /home/mydomain/craftcms/templates/_layout.twig:84

The page URL in the browser has Korean symbols of course, so I guess its too many characters once converted to ascii.
I tried changing it to a Longtext as per another similar issue with a different column, but MySQL will not allow it due to the cacheKey being in the index.
Recommended solutions were to remove the column from the index but to be honest I dont want to start messing with things like this without guidance from Craft.
Is there a Craft recommended approach to this issue please?
Thanks
Is there a Craft recommended approach to this issue please?

The simplest solution would be to update to Craft 3.5+
Template cache data went from being stored in the database to the file system, so this won't be an issue for you anymore.