global search - database index can improve performance dramatically
There was a previous issue, #1688 (closed), which improved the performance of global search. However this can still be inefficient and cause long delays as the number of records increases.
We discovered that the query doesn't use any indexes in the vtiger_crmentity table hence the slowdown, and so by adding a new index to vtiger_crmentity, of type btree on columns setype, deleted & label (in that order) took a query that was taking approx 12 seconds per module, to 0.1ms for each module.
Would add a pull request myself but not sure where to get an index created...