Tuning Indexes - Professional SQL Server 2005 Performance Tuning - page 372

Figure 11-3
When the analysis is complete DTA adds two more tabs: Recommendations and Reports.
For the Insert query, DTA has recommended that you create a clustered index on the lastNames table.
This will reduce the number of reads of the lastNames table from right down to one or two on each query.
Percentage-wise, this is a large reduction.
Now you should implement the recommendation and see what the performance difference is. Start by
looking at the stats time and I/O after adding the clustered index on lastNames. The following is an
abbreviated stats output showing just the key areas that have changed:
-- COLD Run
Table 'lastNames'. Scan count 1, logical reads 9, physical reads 1, read-ahead
reads 7, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'lastNames'. Scan count 0, logical reads 2, physical reads 0, read-ahead
reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
SQL Server Execution Times: