Truncate Table And Stats

Kendra Little shows that TRUNCATE TABLE does not always reset stats:

You might expect to see that the statistic on Quantity had updated. I expected it, before I ran through this demo.

But SQL Server never actually had to load up the statistic on Quantity for the query above. So it didn’t bother to update the statistic. It didn’t need to, because it knows that the table is empty, and this doesn’t show up in our column or index specific statistics.

Check it out.

Related Posts

Pitfalls with Window Functions

Itzik Ben-Gan takes us through two issues you might run into when using window functions: There are two common pitfalls involving window functions, both of which are the result of counterintuitive implicit defaults that are imposed by the SQL standard. One pitfall has to do with calculations of running totals where you get a window […]

Read More

Spaces in CHAR Columns

John McCormack wants to store a single space in a CHAR(1) column: I was asked by a colleague why his where clause wasn’t being selective when filtering on a space value. The column was a char(1) data type. To understand the curious case of the space in char(1), we need to understand how the char […]

Read More

Categories

December 2016
MTWTFSS
« Nov Jan »
 1234
567891011
12131415161718
19202122232425
262728293031