WordPress Code To Improve Bulk Insert Or Update Post Speed
When you hit tens of thousands of posts in WordPress, the speed of
wp_update_post gets significantly slower. To improve the speed, you simply add the following code and you will see that the speed improves significantly.
Add these two lines of code before your insert or update loop
And add these two lines after your insert or update loop
By adding these few lines of code, you are temporarily disabling the term counts until all posts have been inserted or updated to speed up the process