Happy Programming

Index Optimization tips

• Every index increases the time in takes to perform INSERTS, UPDATES
and DELETES, so the number of indexes should not be very much. Try to
use maximum 4-5 indexes on one table, not more. If you have read-only
table, then the number of indexes may be increased.

• Keep your indexes as narrow as possible. This reduces the size of
the index and reduces the number of reads required to read the index.

• Try to create indexes on columns that have integer values rather
than character values.

• If you create a composite (multi-column) index, the order of the
columns in the key are very important. Try to order the columns in the
key as to enhance selectivity, with the most selective columns to the
leftmost of the key.

• If you want to join several tables, try to create surrogate integer
keys for this purpose and create indexes on their columns.

• Create surrogate integer primary key (identity for example) if your
table will not have many insert operations.

• Clustered indexes are more preferable than nonclustered, if you need
to select by a range of values or you need to sort results set with
GROUP BY or ORDER BY.

• If your application will be performing the same query over and over
on the same table, consider creating a covering index on the table.

• You can use the SQL Server Profiler Create Trace Wizard with
"Identify Scans of Large Tables" trace to determine which tables in
your database may need indexes. This trace will show which tables are
being scanned by queries instead of using an index.

• You can use sp_MSforeachtable undocumented stored procedure to
rebuild all indexes in your database. Try to schedule it to execute
during CPU idle time and slow production periods.
sp_MSforeachtable @command1="print '?' DBCC DBREINDEX ('?')"