XML data stored in Postgresql Causes Hang

Hi,

I'm working on a database that stores XML documents as text, and I frequently get a hang when retrieving the XML data. As soon as the query returns, I get an hourglass over a white rectangle at bottom-right of the screen, and the program freezes. The hourglass is not the mouse cursor - that still moves freely.

Trying to close the window gives a message:

/* Cannot close tab with running query. Please wait until query has finished. */

I'm running Windows 11 Pro, the server is running Postresql 9.6 (don't ask!) on CentOS.

I have a query that returns a single row, with an ID and an XML document of about 70K that hangs. The ID displays, but nothing displays in the XML (text) field. The program remains responsive (menus work). Occasionally, the background behind the hourglass is black (I have it displaying in dark mode) with the text "Sorting grid nodes ..."

Any suggestions?

Thanks,

Toby

Is that happening with the latest HeidiSQL?

Yes, it's with 12.4.0.6673, which seems to be the current version. It's been happening for some time though with various versions.