Contents
How to improve the performance of table variables in SQL Server?
With large data, the performance improvement can be significant, from tens of minutes to seconds. Now, the server compiles its code before running each query and does not use the execution plan from the cache, but generates a new one, depending on the amount of data in the variable, and this usually helps a lot.
Why are table variables bad for SQL Server?
Batches or store procedures that execute join operations on table variables may experience performance problems if the table variable contains a large number of rows. Table variable were introduced in SQL Server with the intention to reduce recompiles, however if they are used in batches or store procedures they may cause a performance issue.
How to improve query speed in SQL Server?
Instead I converted the view into a User-Table-Function where the parameter was the value needed on the WHERE clause. In fact this WHERE clause was nested 3 queries deep and it still worked and it was back to the < 10ms speed. Eventually I changed the parameter to be a TYPE that is a table of UtilAcctIds (int).
Why are table variables not used in LINQ?
In the C# code, you can quickly combine the results of both data arrays into one object using LINQ. However, the performance of the query may suffer. The fact is that table variables were not designed for processing large volumes of data. If I’m not mistaken, the query optimizer will be always using the LOOP execution method.
Which is better table variable or temp table?
As with the SQL Profiler results of the INSERT statement this is probably due to the fact that an extra index has to be updated. As with the other scenarios when deleting based on the indexed column the temporary table performs better than the table variable.
Why does the table variable outperform the temporary table?
When deleting rows based on the primary key the table variable outperforms the temporary table. As with the SQL Profiler results of the INSERT statement this is probably due to the fact that an extra index has to be updated.