Faster alternative to regular expression searching for patient identifiers

The current approach for handling patient identifier searches using admin-defined regular expressions is too slow. Regular expression (REGEXP) searches (at least in MySQL) do not use indexes and, therefore, unacceptably slow down the system.

A quick fix is to clear out the patient.identifierRegex global property.

A long-term fix would be to replace the regular expression search with the ability to define a list of search patterns. We need to be able to accommodate leading zeroes and identifier with or without a hyphen.

Add a patient.identifierSearchPattern global property that allows for @SEARCH@, @SEARCH-1@ (search query without last character), and @CHECKDIGIT@ (last character) with commas separating multiple values.

For example, setting patient.identifierSearchPattern to "@SEARCH@,0@SEARCH@,@SEARCH-1@@CHECKDIGIT@,0@SEARCH-1@@CHECKDIGIT@" would turn a request for "4127" into a search for "in ('4127','04127','412-7','0412-7')".

Related tickets: TRAC-142, TRAC-1148, TRAC-1625, TRAC-1802