Reindexing can sometimes run longer than expected

[TheWitness]

Describe the bug

After noticing that a Re-Index was taking a very long time, it was found that during any one single Data Query Re-Index, Graphs and Data Sources for ALL Data Queries are re-evaluated/remapped leading to very long device Re-Index times.

To Reproduce

Steps to reproduce the behavior:

1. Goto a Device with Many Data Queries and some with hundreds to thousands of rows

2. Re-Index on a Data Query with only a few rows.

3. Notice that the Re-Index takes an inordinate amount of time.

Expected behavior

Cacti should be performing optimal Re-Indexes