What is the fastest way to clear a SQL table? - sql-server

Question

I have a table with about 300,000 rows and 30 columns. How can I quickly clear it out? If I do a DROP FROM MyTable query, it takes a long time to run. I'm trying the following stored procedure to basically make a copy of the table with no data, drop the original table, and rename the new table as the original:
USE [myDatabase]
GO
SET ANSI_NULLS_ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER PROCEDURE [dbo].[ClearTheTable]
AS
BEGIN
SET NOCOUNT ON;
SELECT * INTO tempMyTable FROM MyTable WHERE 1 = 0;
DROP TABLE MyTable
EXEC sp_rename tempMyTable, MyTable;
END
This took nearly 7 minutes to run. Is there a faster way to do it? I don't need any logging, rollback or anything of that nature.
If it matters, I'm calling the stored procedure from a C# app. I guess I could write some code to recreate the table from scratch after doing a DROP TABLE, but I didn't want to have to recompile the app any time a column is added or changed.
Thanks!
EDIT
Here's my updated stored procedure:
USE [myDatabase]
GO
SET ANSI_NULLS_ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER PROCEDURE [dbo].[ClearTheTable]
AS
BEGIN
SET NOCOUNT ON;
ALTER DATABASE myDatabase
SET RESTRICTED_USER WITH ROLLBACK IMMEDIATE
TRUNCATE TABLE MyTable
ALTER DATABASE myDatabase
SET MULTI_USER
END

Answer 1

Best way to clear a table is with TRUNCATE.
Since you are creating and droping ill assume you have no constraints.
TRUNCATE TABLE <target table>
Some advantages:
Less transaction log space is used.
The DELETE statement removes rows one at a time and records an entry
in the transaction log for each deleted row. TRUNCATE TABLE removes
the data by deallocating the data pages used to store the table data
and records only the page deallocations in the transaction log.
Fewer locks are typically used.
When the DELETE statement is executed using a row lock, each row in
the table is locked for deletion. TRUNCATE TABLE always locks the
table (including a schema (SCH-M) lock) and page but not each row.
Without exception, zero pages are left in the table.
After a DELETE statement is executed, the table can still contain
empty pages. For example, empty pages in a heap cannot be deallocated
without at least an exclusive (LCK_M_X) table lock. If the delete
operation does not use a table lock, the table (heap) will contain
many empty pages. For indexes, the delete operation can leave empty
pages behind, although these pages will be deallocated quickly by a
background cleanup process.