Reply To: JS performance issues

• John Huebner

• November 10, 2016 at 8:26 am

No solution here, just some thoughts.

There are really 2 issues discussed in this thread. On of them is a slow admin page due to the performance of JavaScript, the other is a slow saving issue. While it may appear to many that these are the same issue, they are in fact to separate issues as far as code and what’s going on.

The JS issue will cause the admin page to be sluggish do to the way that ACF4 tests conditional logic. ACF5 has improved this…. but if you have a highly complex field groups setup with a lot of conditional logic, you’re still probably going to see problems and a slow down.

The second issue, slow saving. This is an issue with the way that WP updates meta values. Every update query for every field in ACF produces at least 4 DB queries. First WP checks to see if there is already a value for a field and then it updates the value for the field. Sometimes it then does a new query to get the new value and populate the cache… why it needs to do this 3rd one, HTH knows. This is done twice for each field because ACF also needs to update the field key reference for the field. This is a limitation of WP because when updating it deals with one meta field at a time. It may be possible to improve this by adding an acf/save_post filter that gets all the post meta for a post before doing an update… but I have not tested this theory. At any rate, given enough fields on a single update it is possible that the update will time out in the browser before it completes. Fixing this problem I suspect is beyond the scope of what ACF is meant to do. Now, if someone could come up with a way to bypass this one at a time field update…. I’ve thought about it but I simple don’t have the time.

On top of both of these issues is the fact that validation of field values is done on the server using AJAX. Part of the reason for this is to allow us, the developers, to create custom validation filters. This is an extra step that means the a post is actually sent to the server twice before it’s updated.

My solution is to consider the limitations and plan my development around those limitations. What is logically possible and what is possible in practice are not the always the same thing. If I give a user a repeater field to add images and content with I expect them to be practical and not add 10,000 images to the repeater, although I wouldn’t be surprised if they tried.