Updating of Field Layouts is an expensive process

Summary

Updating of FieldLayouts is expensive because whenever any change to FieldLayout happens there has to be a synchronized opperation done that removes all FieldLayoutItems for that FieldLayout and creates them all again (This is an order of magnitude of a number of custom fields so for large instances with thousands of custom fields editing FieldLayouts can become a major problem). Even if we change description of only a single FieldLayoutItem all items need to be recreated..

Environment

• Large number of custom fields: 1500+
• Large number fieldlayout (Field Configuration):

  SQL> select count(1) from fieldlayout; 
  576 
  
  SQL> select count(1) from fieldlayoutitem; 
  1355666
  

Steps to Reproduce

Using a very large instance, edit a field configuration.

Expected Results

JIRA does not remove all FieldLayoutItems for that FieldLayout and creates them all again.

Actual Results

JIRA executes a very high amount of SQL, as it removes all FieldLayoutItems for that FieldLayout and creates them all again. SQL similar to:

INSERT INTO public.fieldlayoutitem (ID, FIELDLAYOUT, FIELDIDENTIFIER, DESCRIPTION, VERTICALPOSITION, ISHIDDEN, ISREQUIRED, RENDERERTYPE) VALUES (?, ?, ?, ?, ?, ?, ?, ?)