The indexes are used to optimize queries. The index statistics are use by SQL Server query processor to determine an execution plan for a query.

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>I've been playing with the DTA (Database Tuning Advisor) and if I tried to optimize a query it then suggests some recommendations to create indexes and statistics. My question is what are the purpose of the statistics? Will they occupy huge disk space? Are they going to affect the speed on retrieving, updating and inserting data?
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>Thanks in advance....