What really happens internally when an update happens on a record with indexed column in sql server -


i know when table has indexed column(s), sql server duplicates data of these columns can accessed fast without looking through every record. , if index covered other columns these included columns stored along indexed columns.

so, assuming when update happens on of indexed columns or included columns obvious update should happen in both actual record location , index location. point looks interesting me because if table expected have more updates searches, wouldn't overhead have index? wanted confirm on , know internals on happens behind screen when update happens.

yes, have correct. there trade-off when adding indexes. have potential make selects faster, make updates/inserts/deletes slower.


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