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 SqlServer — Store Procedure Performance Issue

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ssfier
Starting Member

2 Posts

Posted - 2012-01-30 : 09:13:33
--I have a table that's being inserted every night and then queried as a reporting table.
--the store proc that works for the query, has dynamic sql string, paging and two temporary tables within it.
--it works well for the first week
--starting from the second week, its performance starts to drop sharply
--I have acquired and then run the output string of the dynamic sql, it's dramatically faster, so I guess it could be related to compiler
--then I did some optimization, like changing count(*) to count(event_id), the performance is immediately back, but the next morning the performance is down again.
--then I changed 'select into' to declaring the temp table explicitly, the performance is immediately back, but the next morning the performance is down again.
--then I changed declaring the temp table explicitly back to 'select into', the performance is immediately back, but the next morning the performance is down again.
--so I guess it has nothing to do with code optimization, it seems every time the SP got compiled, the performance can be better for only less than 24 hours
--I am thinking about the nightly insertion, which is also 24 hours' cycle, then I found this no (nolock) thing, which could have locked up Table1
--After adding Nolock, the store procedure ran well for a week, after which we got the same problem again, except that this time, only the web page calling the SP is slow, running SP from DB is fast…
--If you have time, please give me some clue here.
--Here is the dynamic sql store proc:


CREATE PROCEDURE [dbo].[fs_1_usp_query]
@paramerter_client_id int = null,
@paramerter_event_type_id int = null,
@paramerter_start_date datetime = null,
@paramerter_end_date datetime = null,
@paramerter_page_index int = 1,
paramerter_sort_direction varchar(20),
@paramerter_page_count int = 30
AS
BEGIN
SET ARITHABORT ON;
SET NOCOUNT ON;

declare @sql nvarchar(max)

set @sql = '

create table #output2
(
page_index int,
rownumber int,
page_count int,
client_id int,
date datetime,
)




--insert into #output1
select
page_count = count(event_id) over(),
table1.*
into #output1'
set @sql = @sql + '
from
table1 table1 with (nolock)
inner join
table2 table2 with (nolock)
on
............................
inner join
table3 table3 with (nolock)
on
............................
inner join
table4 table4
on
............................
where
............................

if (@paramerter_client_id is not null)
set @sql = @sql + ' and table2.client_id = @paramerter_client_id'

if (@paramerter_event_type_id is not null)
set @sql = @sql + ' and table2.event_type_id = @paramerter_event_type_id'

if (@paramerter_start_date is not null)
set @sql = @sql + ' and table2.created_date >= @paramerter_start_date'
if (@paramerter_end_date is not null)
set @sql = @sql + ' and table2.created_date <= @paramerter_end_date'

declare @lv_begin_index int
declare @lv_end_index int
set @lv_begin_index = ((@paramerter_page_index - 1) * @paramerter_page_count) + 1
set @lv_end_index = @lv_begin_index + @paramerter_page_count

set @sql = @sql + '

UPDATE #output1
SET osat_rating = ''-''
WHERE LEFT( osat_rating , 1 ) = ''-''

insert into #output2
select
page_index = ' + convert(varchar, @paramerter_page_index) + ',
row_number() over (order by [' + @paramerter_sort_expression + '] '+ @paramerter_sort_direction + ') as rownumber,
#output1.*
from #output1

select #output2.*
from #output2
where
rownumber >= ' + convert(varchar, @lv_begin_index) + '
and
rownumber < ' + convert(varchar, @lv_end_index) '

set @sql = @sql + '
drop table #output1
drop table #output2 '

visakh16
Very Important crosS Applying yaK Herder

52326 Posts

Posted - 2012-01-30 : 11:40:59
i guess you know potential problem using nolock
http://visakhm.blogspot.com/2010/02/avoiding-deadlocks-using-new.html

now for the sp performance i think it might be due to bad plan getting cached. can you try WITH RECOMPILE clause and see if it helps?

------------------------------------------------------------------------------------------------------
SQL Server MVP
http://visakhm.blogspot.com/

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ssfier
Starting Member

2 Posts

Posted - 2012-02-14 : 09:43:26
Thanks for the tips, :=)
Yes, regarding Plan Caching, I am taking off dynamic strings and doing static SQL, hopefully within the next two weeks I will get back here with an update whether this will work out:

Where
Column3 = Coalesce(@parameter3, Column3)
and
(@parameter_start_date is null or Column_created_date >= @parameter_start_date)

and
(@parameter_1 is null
or
(@parameter_1 not in (‘ConstantString1’, 'ConstantString2’) and Column1 = @parameter_1)
or
(@parameter_1 = ‘ConstantString1’ and Column1 like 'ConstantString1%')
or
(@parameter_1 = ‘ConstantString2’ and (Column1 is null or Column1 = ''))
)


If(@parameter_sort_direction = 'DESC')
Begin
insert into #temp_table_result
select
page_index = convert(varchar, @parameter_page_index),
row_number() over
(
order by CASE
WHEN @parameter_sort_expression = 'Column1' THEN Column1
WHEN @parameter_sort_expression = 'Column2' THEN Column2
WHEN @parameter_sort_expression = 'Column3' THEN Column3
WHEN @parameter_sort_expression = 'Column4' THEN Column4
WHEN @parameter_sort_expression = 'Column5' THEN Column5
WHEN @parameter_sort_expression = 'Column6' THEN Column6
WHEN @parameter_sort_expression = 'Column7' THEN Column7
WHEN @parameter_sort_expression = 'Column8' THEN Column8
END desc--CASE
-- WHEN @parameter_sort_direction = 'ASC' THEN asc
-- WHEN @parameter_sort_expression = 'DESC' THEN desc
--END
) as rownumber,
#temp_table_staging.*
from #temp_table_staging
END
ELSE
Begin
insert into #temp_table_result
select
page_index = convert(varchar, @parameter_page_index),
row_number() over
(
order by CASE
WHEN @parameter_sort_expression = 'Column1' THEN Column1
WHEN @parameter_sort_expression = 'Column2' THEN Column2
WHEN @parameter_sort_expression = 'Column3' THEN Column3
WHEN @parameter_sort_expression = 'Column4' THEN Column4
WHEN @parameter_sort_expression = 'Column5' THEN Column5
WHEN @parameter_sort_expression = 'Column6' THEN Column6
WHEN @parameter_sort_expression = 'Column7' THEN Column7
WHEN @parameter_sort_expression = 'Column8' THEN Column8
END asc
) as rownumber,
#temp_table_staging.*
from #temp_table_staging
END


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visakh16
Very Important crosS Applying yaK Herder

52326 Posts

Posted - 2012-02-14 : 09:58:19
the set of or condition in where clause can also cause bad query plans getting created and cause query to perform poorly especially for large datasets. In such cases, using dynamic sql with sp_executesql may perform better

------------------------------------------------------------------------------------------------------
SQL Server MVP
http://visakhm.blogspot.com/

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