Question

I have a stored procedure inside which I create a temporary table that typically contains between 1 and 10 rows. This table is truncated and filled many times during the stored procedure. It is truncated as this is faster than delete.
Do I get any performance increase by replacing this temporary table with a table variable when I suffer a penalty for using delete (truncate does not work on table variables)

Whilst table variables are mainly in memory and are generally faster than temp tables do I loose any benefit by having to delete rather than truncate?

Answer 1

Running the followign to scripts, it would seem that the Table Variable is the better option

CREATE TABLE #Temp(
        ID INT
)

DECLARE @Int INT,
        @InnerInt INT
SELECT  @Int = 1,
        @InnerInt = 1

WHILE @Int < 50000
BEGIN
    WHILE @InnerInt < 10
    BEGIN
        INSERT INTO #Temp SELECT @InnerInt
        SET @InnerInt = @InnerInt + 1
    END
    SELECT @Int = @Int + 1,
            @InnerInt = 1
    TRUNCATE TABLE #Temp
END

DROP TABLE #TEMP

GO

DECLARE @Temp TABLE(
        ID INT
)

DECLARE @Int INT,
        @InnerInt INT
SELECT  @Int = 1,
        @InnerInt = 1

WHILE @Int < 50000
BEGIN
    WHILE @InnerInt < 10
    BEGIN
        INSERT INTO @Temp SELECT @InnerInt
        SET @InnerInt = @InnerInt + 1
    END
    SELECT @Int = @Int + 1,
            @InnerInt = 1
    DELETE FROM @Temp
END

From Sql Profiler

CPU     Reads   Writes  Duration
36375     2799937   0       39319

vs

CPU     Reads   Writes  Duration
14750   1700031 2       17376