Sql 2016 updating a substring in a char field dobson on dating
A value of 0 inserts the new data at the beginning of the existing data.
Plan for computation: CSel Calc Fixed Filter (0.1) The table contains a million rows. Under compat level 130 the 10% guess yields an estimate of 100,000. The 120 behaviour uses the histogram but only to get the number of distinct rows.When the data stream is not present the query processor ignores the BULK option.Is the name of the table and text, ntext, or image column to be updated.Is there any documentation or research about changes in SQL Server 2016 to how cardinality is estimated for predicates containing SUBSTRING() or other string functions? Adding reverts the estimate going into the sort to 100,000 but the memory grant doesn't increase and the estimates coming out the sort are still based on the table distinct values.The reason I'm asking is that I was looking at a query whose performance degraded in compatibility mode 130 and the reason was related a change in the estimate of the number of rows that match a WHERE clause that contained a call to SUBSTRING(). Similarly tweaking the cost threshold for parallelism so that the query gets a parallel plan was sufficient in the 130 case to revert to the lower estimate.