Updating index statistics sql
Some other more complicated scenarios include when you have jobs which rebuild your indexes based on their fragmentation level.
Of course, the worst case scenario would be if you first rebuild your indexes, which also updates the index statistics by scanning the entire table, and later you run UPDATE STATISTICS using the default values, which again updates the index statistics but this time only with a default and smaller sample.
If someone asks you the question “Does rebuild index update statistics? You may be surprised to know that index rebuild doesn’t update all statistics.
when you use alter index rebuild, only statistics associated with that index will be updated.
Quite a few facts ended up surprising the audience.
I thought I’d share a few and wanted to start with index rebuild.
REORGANIZE statement, does not update any statistics.
4) Reorganizing an index, for example using the ALTER INDEX …In order to illustrate this better, let’s draw a table Note that non-index stats means the statistics associated with a column/columns that are automatically created or manually created.As you can see from above, don’t assume all of your statistics get updated just because you have a maintenance plan to rebuild index.You can validate that only the column statistics were updated by looking at the update_date column which uses the STATS_DATE function to display the last date the statistics were updated.Benjamin Nevarez is a database professional based in Los Angeles, California who specializes in SQL Server query tuning and optimization.
Sometimes, non-index statistics are very critical as well.