Fatal error: Call to undefined function mysql_pconnect() ....

I refer you to http://www.webassist.com/forums/posts.php?id=38086, where you finished by saying:
"You can use the MySQLi server behaviors. You would just have to create a MySQLi connection and then start using those server behaviors on your pages. DataBridge v2 includes functionality to update existing MySQL pages to MySQLi as well."

I was eventually forced to upgrade PHP to 7.1, and immediately started getting 500 errors from all my other pages, which depend upon queries and recordsets for varied kinds of information on those pages.
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When it eventually occurred to me to examine the site log files, I traced the likely difficulty down to a call to a "MySQL_pconnect" function.

I have used DataAssist to create a new MySQLi connection.

I am now wondering on a best practices method for how to proceed.

Your above suggestion seems to imply that there is a way in which DataAssist would automatically correct all relevant recordsets and the like for me, but I am undertain how to invoke this. That would of course be easiest for me by way of preventing further errors.

Failing that, is it better to delete a recordset befor creating a new recordset of the desired type, which of course requires that I use the old MySQL format as a model for the data I require, whilst being uncertain of the desired result and etc.

Thank you for your assistance in determining a best way forwards.
KB