Cater for noderef select fields which may have many entries

[bobbingwide]

There is a limit to how many posts can be loaded when populating the select list for a noderef field. When there are thousands of nodes the #options array becomes quite unwieldly.
Also there is a distinct possibility that the server runs out of memory.

When editing an oik_hook post type ( part of the oik-shortcodes plugin ), the Fields metabox fails to display due to.

Fatal error: Allowed memory size of 268435456 bytes exhausted (tried to allocate 16781312 bytes) in C:\apache\htdocs\wporg\wp-includes\functions.php on line 3464

This is because there are over 16K posts with post type of oik_api.

Ditto for any other post type that attempts to display a select field for a noderef of post type oik_api

Workaround

Exclude the fields from the Fields meta box by not registering its association to the post type.

Proposed solution

Implement a select2 like field or another solution that works with mega data.

Note: The logic to load a noderef field's values ( bw_load_noderef2() ) is actually part of the oik plugin.