This means that the columns returned by either the SELECT clause and all the WHERE and JOIN arguments are covered by the index. There's potentially much less I/O to execute the query, if the index is narrow enough when compared to the rows and columns in the table itself, meaning it's...
This means that the columns returned by either the SELECT clause and all the WHERE and JOIN arguments are covered by the index. There's potentially much less I/O to execute the query, if the index is narrow enough when compared to the rows and columns in the table itself, meaning ...
This means long-term blocking table locks aren't held and queries or updates to the data in the underlying table can continue during the ALTER INDEX REORGANIZE transaction. Not allowed for a disabled index. Not allowed when ALLOW_PAGE_LOCKS is set to OFF. Not rolled back when performed ...
How the counters in the Metadata Cache are reset The data returned by sys.dm_db_index_operational_stats exists only as long as the metadata cache object that represents the heap or index is available. This data is neither persistent nor transactionally consistent. This means you cannot use the...
If a re-index was not actually needed, starting and then cancelling a re-index will do no harm at all. If a configuration change means a re-index is required, then the re-index will still be required and should be allowed to run to completion at some time in the near future....
Covering indexes are the designation for a nonclustered index that resolves one or several similar query results directly with no access to its base table, and without incurring in lookups. Such indexes have all the necessary non-SARGable columns in its leaf level. This means that the columns ...
This means that the columns returned by either the SELECT clause and all the WHERE and JOIN arguments are covered by the index. There is potentially much less I/O to execute the query, if the index is narrow enough when compared to the rows and columns in the table itself, meaning it ...
The fill-factor value is a percentage from 1 to 100, and the server-wide default is 0 which means that the leaf-level pages are filled to capacity. Note Fill-factor values 0 and 100 are the same in all respects. In This Topic Before you begin: Performance Considerations Security To spec...
The data returned bysys.dm_db_index_operational_statsexists only as long as the metadata cache object that represents the heap or index is available. This data is neither persistent nor transactionally consistent. This means you cannot use these counters to determine whether an index has been us...
This means that it requires 2 pages. The final level of the index has to store 2 rows. This means that it requires 1 page. This yields 43 non-leaf index pages. When these numbers are used in the previous formulas, the result is as follows: Non-leaf_Levels = 1 + log(25) (1000 ...