Configuration Enforcement

by Nov 30, 2016

This post is a companion to the webcast today. I’ll update it once the webcast airs and I have the recording up.

Here is the complete set of scripts from the webcast I was using.

-- turn on optimize for ad hoc workloads
EXEC sys.sp_configure N'optimize for ad hoc workloads', N'1'
GO
RECONFIGURE WITH OVERRIDE
GO

-- turn off optimize for ad hoc workloads
EXEC sys.sp_configure N'optimize for ad hoc workloads', N'0'
GO
RECONFIGURE WITH OVERRIDE
GO

/* from user Kin on dba.stackexchange.com
dba.stackexchange.com/.../why-would-i-not-use-the-sql-server-option-optimize-for-ad-hoc-workloads
*/

--- for 2008 and up .. Optimize ad-hoc for workload
IF EXISTS (
-- this is for 2008 and up
SELECT 1
FROM sys.configurations
WHERE NAME = 'optimize for ad hoc workloads'
)
BEGIN
DECLARE @AdHocSizeInMB DECIMAL(14, 2)
,@TotalSizeInMB DECIMAL(14, 2)
,@ObjType NVARCHAR(34)

SELECT @AdHocSizeInMB = SUM(CAST((
CASE
WHEN usecounts = 1
AND LOWER(objtype) = 'adhoc'
THEN size_in_bytes
ELSE 0
END
) AS DECIMAL(14, 2))) / 1048576
,@TotalSizeInMB = SUM(CAST(size_in_bytes AS DECIMAL(14, 2))) / 1048576
FROM sys.dm_exec_cached_plans

SELECT 'SQL Server Configuration' AS GROUP_TYPE
,' Total cache plan size (MB): ' + cast(@TotalSizeInMB AS VARCHAR(max)) + '. Current memory occupied by adhoc plans only used once (MB):' + cast(@AdHocSizeInMB AS VARCHAR(max)) + '. Percentage of total cache plan occupied by adhoc plans only used once :' + cast(CAST((@AdHocSizeInMB / @TotalSizeInMB) * 100 AS DECIMAL(14, 2)) AS VARCHAR(max)) + '%' + ' ' AS COMMENTS
,' ' + CASE
WHEN @AdHocSizeInMB > 200
OR ((@AdHocSizeInMB / @TotalSizeInMB) * 100) > 25 -- 200MB or > 25%
THEN 'Switch on Optimize for ad hoc workloads as it will make a significant difference. Ref: sqlserverperformance.idera.com/.../. www.sqlskills.com/.../procedure-cache-and-optimizing-for-adhoc-workloads.aspx'
ELSE 'Setting Optimize for ad hoc workloads will make little difference !!'
END + ' ' AS RECOMMENDATIONS
END

/* modified for our use in uptime to return just how many MB are used for adhoc query plan storage
200 MB or more is the recommended size for using optimize for ad hoc workloads */
IF EXISTS (
-- this is for 2008 and up
SELECT 1
FROM sys.configurations
WHERE NAME = 'optimize for ad hoc workloads'
)
BEGIN
DECLARE @AdHocSizeInMB DECIMAL(14, 2)
,@TotalSizeInMB DECIMAL(14, 2)
,@ObjType NVARCHAR(34)

SELECT @AdHocSizeInMB = SUM(CAST((
CASE
WHEN usecounts = 1
AND LOWER(objtype) = 'adhoc'
THEN size_in_bytes
ELSE 0
END
) AS DECIMAL(14, 2))) / 1048576
,@TotalSizeInMB = SUM(CAST(size_in_bytes AS DECIMAL(14, 2))) / 1048576
FROM sys.dm_exec_cached_plans

SELECT cast(@AdHocSizeInMB AS VARCHAR(max))
END

-- reconfigure if we see the value set false

IF (SELECT value FROM sys.configurations WHERE NAME = 'optimize for ad hoc workloads') = 0
-- turn on optimize for ad hoc workloads
BEGIN
EXEC sys.sp_configure N'optimize for ad hoc workloads', N'1'
RECONFIGURE WITH OVERRIDE
END
ELSE
BEGIN
select 1;
END