Execution Plans Inconsistent With Performance
May 16, 2008
I've been working with SQL Server 2005 for a while now and I've noticed some odd behavior that I want to bounce of other members of the community. I should preface that I've been a forum viewer (and occasional contributer) here at SQL Team for a while and I've naturally developed a keen sense for optimizations.
Fundamentally, longer stored procedures with perfectly fine/optimized execution plans are inconsistent with real world performance. In some of these cases, a low subtree cost on a 4 core machine with 16gb of ram and 2 15 drive SAS arrays with little load takes excessively long to run or in some cases doesn't complete.
This isn't due to blocking or resource bottlenecks as I'm quite familiar with built in tools to troubleshoot and resolve those issues. In all cases, I am able to rearchitect the stored procedure into a higher subtree cost variant and get reasonable performance, but it's frustrating to have to redo work and there seems to be no common theme other than longer multi-statement procedures.
I've used SQL Server 2000 extensively and did not notice this level of inconsistency in performance with that product version. Just wondering if others in the community have experiences similar or if I'm just crazy.
Thanks for reading my rant.
- Shane
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Dec 7, 2005
Hi I am slowly getting to grips with SQL Server. As a part of this, I have been attempting to work on producing more efficient queries. This post is regarding what appears to be a discrepancy between the SQL Server execution plan and the actual time taken by a query to run. My brief is to produce an attendance system for an education establishment (I presume you know I'm not an A-Level student completing a project :p ). Circa 1.5m rows per annum, testing with ~3m rows currently. College_Year could strictly be inferred from the AttDateTime however it is included as a field because it a part of just about every PK this table is ever likely to be linked to. Indexes are not fully optimised yet. Table:CREATE TABLE [dbo].[AttendanceDets] ([College_Year] [smallint] NOT NULL ,[Group_Code] [char] (12) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL ,[Student_ID] [char] (8) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL ,[Session_Date] [datetime] NOT NULL ,[Start_Time] [datetime] NOT NULL ,[Att_Code] [char] (1) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL ) ON [PRIMARY]GO CREATE CLUSTERED INDEX [IX_AltPK_Clust_AttendanceDets] ON [dbo].[AttendanceDets]([College_Year], [Group_Code], [Student_ID], [Session_Date], [Att_Code]) ON [PRIMARY]GO CREATE INDEX [All] ON [dbo].[AttendanceDets]([College_Year], [Group_Code], [Student_ID], [Session_Date], [Start_Time], [Att_Code]) ON [PRIMARY]GO CREATE INDEX [IX_AttendanceDets] ON [dbo].[AttendanceDets]([Att_Code]) ON [PRIMARY]GOALL inserts are via an overnight sproc - data comes from a third party system. Group_Code is 12 chars (no more no less), student_ID 8 chars (no more no less). I have created a simple sproc. I am using this as a benchmark against which I am testing my options. I appreciate that this sproc is an inefficient jack of all trades - it has been designed as such so I can compare its performance to more specific sprocs and possibly some dynamic SQL. Sproc:CREATE PROCEDURE [dbo].[CAMsp_Att] @College_Year AS SmallInt,@Student_ID AS VarChar(8) = '________', @Group_Code AS VarChar(12) = '____________', @Start_Date AS DateTime = '1950/01/01', @End_Date as DateTime = '2020/01/01', @Att_Code AS VarChar(1) = '_' AS IF @Start_Date = '1950/01/01'SET @Start_Date = CAST(CAST(@College_Year AS Char(4)) + '/08/31' AS DateTime) IF @End_Date = '2020/01/01'SET @End_Date = CAST(CAST(@College_Year +1 AS Char(4)) + '/07/31' AS DateTime) SELECT College_Year, Group_Code, Student_ID, Session_Date, Start_Time, Att_Code FROM dbo.AttendanceDets WHERE College_Year = @College_YearAND Group_Code LIKE @Group_CodeAND Student_ID LIKE @Student_IDAND Session_Date <= @End_DateAND Session_Date >=@Start_DateAND Att_Code LIKE @Att_CodeGOMy confusion lies with running the below script with Show Execution Plan:--SET SHOWPLAN_TEXT ON--Go DECLARE @Time as DateTime Set @Time = GetDate() select College_Year, group_code, Student_ID, Session_Date, Start_Time, Att_Code from attendanceDetswhere College_Year = 2005 AND group_code LIKE '____________' AND Student_ID LIKE '________'AND Session_Date <= '2005-11-16' AND Session_Date >= '2005-11-16' AND Att_Code LIKE '_' Print 'First query took: ' + CAST(DATEDIFF(ms, @Time, GETDATE()) AS VarCHar(5)) + ' milli-Seconds' Set @Time = GetDate() EXEC CAMsp_Att @College_Year = 2005, @Start_Date = '2005-11-16', @End_Date = '2005-11-16' Print 'Second query took: ' + CAST(DATEDIFF(ms, @Time, GETDATE()) AS VarCHar(5)) + ' milli-Seconds'GO --SET SHOWPLAN_TEXT OFF--GOThe execution plan for the first query appears miles more costly than the sproc yet it is effectively the same query with no parameters. However, my understanding is the cached plan substitutes literals for parameters anyway. In any case - the first query cost is listed as 99.52% of the batch, the sproc 0.48% (comparing the IO, cpu costs etc support this). BUT the text output is:(10639 row(s) affected) First query took: 596 milli-Seconds (10639 row(s) affected) Second query took: 2856 milli-SecondsI appreciate that logical and physical performance are not one and the same but can why is there such a huge discrepancy between the two? They are tested on a dedicated test server, and repeated running and switching the order of the queries elicits the same results. Sample data can be provided if requested but I assumed it would not shed much light. BTW - I know that additional indexes can bring the plans and execution time closer together - my question is more about the concept. If you've made it this far - many thanks.If you can enlighten me - infinite thanks.
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Dec 4, 2007
Greetings,
I have a somewhat complex stored procedure running on 3 production servers. On 2 of the 3 servers the stored procedure executes in three seconds. The stored procedure runs to completion on the 3rd production server but requires 8 minutes to complete.
The sproc contains a single query that contains correlated subqueries that each call the same user function. If I copy the sproc's query and execute it directly from Management Studio, the query runs in 3 seconds, just like the stored procedure on the other two production servers. The sproc has one parameter.
I have updated statistics and recompiled the stored procedure and user function (on the 8 minute server). That doesn't help. I have used the WITH RECOMPILE option in the stored procedure. The query execution plan for the stored procedure is not the same execution plan prepared for the sproc's query when it is run on a standalone basis. I'm no expert with execution plan analysis but I can see significant differences between the sproc and the sproc's query.
The 3 servers are supposed to be identical in hardware and software configuration.
Can anyone provide any insight into what might be going wrong on the 8 minute server?
Thanks,
BCB
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Nov 16, 2001
I have two schematically identical databases on the same MS SQL 2000 server. The differences in the data are very slight. Here is my problem: the identical query has totally different execution plans on the different databases. One is (in my opinion) correct, the other causes the query to take 60 times as long. This is not an exaggeration, on the quick DB the query takes 3 seconds, on the other DB it takes 3 minutes. I have tried the following to help the optimizer pick a better execution plan on the slow db:
rebuild the indexes
dbcc indexdefrag
update statistics
I CAN put in a hint to cause the query to execute faster, but my employer now knows about the problem and he (and I) want to know WHY this is happening.
Any ideas would be greatly appreciated.
Thanks.
-Scott
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Jul 23, 2005
HiCan you give me sone pointers to where I can get more information aboutthe various operations like index seeks,Bookmark Lookups,ClusteredIndex Scan in an execution plan.ThanksRagu
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Jun 8, 2006
One of my developers recently installed a backup of the production database onto his test site. His test server has the same configuration as the production server.
One of the Stored Procedures that is called takes 1:45 to run on his machine, but only 2 seconds on the production server. This same SP takes only 2 seconds on my development database.
The SP is called iteratively, up to 10 times... to run against 10 separate fields. Depending on a value for a parameter called @CriteriaClassID, depends on which portion of the SP runs.
The significant difference in processing time in itself is baffling (since the servers are same specs / configuration, as far as I can tell, and the data is identical, since he has a backup of the most recent production data).
But more baffling: if, in his data, I switch the values from field 1 to field 2, and vice versa, his results take 2 seconds (switching the values in field 1 to field 2 switches the value in @CriteriaClassID which is passed through to this SP).
It's exactly the same SP; the only difference is that field 1 is processed first, field 2 second, field 3 third etc. On the production site and my development site, it doesn't make a difference in the order they are processed. On his machine it does.
Any ideas? I though perhaps his Indexes were corrupted in the rebuild, but we ran a SQL Server maintenance schedule to clean it up, and no improvement.
This is the SP, if it is of any help:
CREATE procedure [dbo].[st_pull_model_data] @ModelID as integer, @CriteriaID as integer
as
declare @ClientID as integer, @CriteriaClassId as char(1)
/*Procedure to pull data from org_model_data and postalcode_model_data for modeling and media analysis */
/*Need to have table #temp_data created outside of SP with fields org_id and zip_code */
/*This procedure is used by SP st_model_data */
If @CriteriaID is not null
begin
set @CriteriaClassId = (Select model_criteria_type from model_criteria where model_criteria_id = @CriteriaID)
if @CriteriaClassID = 'G' -- changes client_id from specific to general, if General is required.
begin
set @ClientID = 0
end
else
begin
set @ClientID = (Select client_id from model where model_id = @ModelID)
end
If @CriteriaClassId in ('G','P')
Begin
update#temp_data
setdata1 = postal_criteria_value
from #temp_data t
left outer join
(select postalcode, postal_criteria_value
from postalcode_model_data pmd
join model_org_trade_area mota on mota.zip_code = pmd.postalcode
join model_org mo on mo.model_org_id = mota.model_org_id
where model_criteria_id = @CriteriaID
and client_id = @ClientID
and mo.model_id = @ModelID) as PMD
onPMD.postalcode = t.zip_code
end
else
Begin
update#temp_data
setdata1 = org_criteria_value
from#temp_data t
left outer join
(select distinct postalcode, org_criteria_value, omd.org_id
from org_model_data omd
join org o on o.org_id = omd.org_id
join model_org_trade_area mota on mota.zip_code = omd.postalcode
join model_org mo on mo.model_org_id = mota.model_org_id and mo.org_id = o.org_id
where model_criteria_id = @CriteriaID and o.client_id = @ClientID and mo.model_id = @ModelID) as OMD
on OMD.postalcode = t.zip_code and omd.org_id = t.org_id
end
end
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Feb 13, 2007
Basically, I have a web-based application that queries aggregates from several big tables that grow rather quickly. I feel I am fairly accomplished at tuning individual queries and have optimized these particular stored procedures as much as I can and often see great results for a period of time. However, after time passes, it seems the stored procedures begins performing really badly. What's frustrating is that I have traced the server, located a stored procedure that consistently executes with an abnormally high duration, but when I run the exact same text directly against the sql server it returns instantly.
If I recompile the stored procedure using my direct connection by including the WITH RECOMPILE clause to the EXEC statement, the problem remains for the web-app. However, if I add the WITH RECOMPILE to the actual stored procedure, it is instantly resolved. I can then remove the WITH RECOMPILE from the stored procedure text and things will remain speedy for a period of time before they again slip back.
I'm curious as to what I can do from a SQL standpoint to correct for this. For now, the app team is setting a counter for each execution and then issuing a WITH RECOMPILE when the counter limit is exceeded.
I apologize if this question has most been asked before and I have attempted a review of the forums but was unable to find any material. Any suggestions, advice, links or general assistance would be most appreciated.
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Jul 23, 2005
Hi,I am facing a peculiar problem while looking ahead in a live Databasecurrently under operation in one of my client’s Project. AnApplication that is updating 3 - tables in the Database is missing toupdate a certain number of Fields in one of the Tables. The fact isnot frequent and I have checked through the Server Performance Monitorthat there is no performance slag of the Server during any point oftime.The Tables are indexed with common Key fields. Can anybody help me inthis regard ?Thanks & Regards.--Posted using the http://www.dbforumz.com interface, at author's requestArticles individually checked for conformance to usenet standardsTopic URL: http://www.dbforumz.com/General-Dis...pict193836.htmlVisit Topic URL to contact author (reg. req'd). Report abuse: http://www.dbforumz.com/eform.php?p=655931
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Nov 13, 2006
Hi everyone! I have a very brief question... I have 10 queues in my database and each of them are sent equal number of messages... There are instances where they execute/activate the stored procedures very fast but there are times where they don't, does anyone have an idea why this happens?
Thank you very much for taking the time to read my post. :)
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Apr 15, 2008
Hi Gurus,
What permissio0ns one should have to view execution plans on SQL SERVER 2005.
Thanks,
ServerTeam
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Jul 23, 2005
I'm looking for assistance on a problem with SQL Server. We have adatabase where a particular query returns about 3000 rows. This querytakes about 2 minutes on most machines, which is fine in thissituation. But on another machine (just one machine), it can run forover 30 minutes and not return. I ran it in Query Analyzer and it wasreturning about 70 rows every 45-90 seconds, which is completelyunacceptable.(I'm a developer, not a DBA, so bear with me here.)I ran an estimated execution plan for this database on each machine,and the "good" one contains lots of parallelism stuff, in particularthe third box in from the left. The "bad" one contains a "Nested Loop"at that position, and NO parallelism.We don't know exactly when this started happening, but we DO know thatsome security updates have been installed on this machine (it's at theclient location), and also SP1 for Office 2003.So it looks like parallelism has been turned off by one of these fixes.Where do we look for how to turn it back on? This is on SQL Server2000 SP3.Thanks for any help you might have for me!Christine Wolak -- SPL WorldGroup --Join Bytes!
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Jul 16, 2007
Hi,We are trying to solve a real puzzle. We have a stored procedure thatexhibits *drastically* different execution times depending on how itsexecuted.When run from QA, it can take as little as 3 seconds. When it iscalled from an Excel vba application, it can take up to 180 seconds.Although, at other times, it can take as little as 20 seconds fromExcel.Here's a little background. The 180 second response time *usually*occurs after a data load into a table that is referenced by the storedprocedure.A check of DBCC show_statistics shows that the statistics DO getupdated after a large amount of data is loaded into the table.*** So, my first question is, does the updated statistics force arecompile of the stored procedure?Next, we checked syscacheobjects to see what was going on with theexecution plan for this stored procedure. What I expected to see wasONE execution plan for the stored procedure.This is not the case at all. What is happening is that TWO separateCOMPILED PLANs are being created, depending on whether the sp is runfrom QA or from Excel.In addition, there are several EXECUTABLE PLANs that correspond to thetwo COMPILED PLANs. Depending on *where* the sp is run, the usecountincreases for the various EXECUTABLE PLANS.To me, this does not make any sense! Why are there *multiple* compileand executable plans for the SAME sp?One theory we have is, that we need to call the sp with the dboqualifier, ie) EXEC dbo.spHas anyone seen this? I just want to get to the bottom of this andfind out why sometimes the query takes 180 seconds and other timesonly takes 3 seconds!!Please help.Thanks much
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May 8, 2007
Hi all,
I have a table TableA with few million rows. When I query TableA , the execution plans changes based on the input parameter as shown below . Why this happens ? How to resolve this ? Any inputs would be appreciated.
SELECT * FROM TableA WHERE Column1 = 1 => SELECT -> Clustered Index Scan (100%)
SELECT * FROM TableA WHERE Column1 = 2 => SELECT -> Clustered Index Scan (100%)
SELECT * FROM TableA WHERE Column1 = 3 => SELECT -> Parallelism (3%) -> Clustered Index Scan (97%)
SELECT * FROM TableA WHERE Column1 = 4 => SELECT -> Nested Loops -> Index Seek (50%) -> Clustered Index Seek (50%)
(takes a very long time to retrieve the records)
Thanks in advance,
DBLearner.
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Jun 21, 2006
Does SQLCE 3 cache execution plans? Or even make use of them?
Thanks
Tryst
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Feb 13, 2006
Hi -Trying to chase down a baffling performance issue. Our database has beenrunning very slow lately. So we are performance tuning the database. Indoing so, we created a copy of our production database. In that database, Ichanged one clustered index on a table to try to improve performance. I ranone query - saw a slight improvement - but saw "lazy spool" in the executionplan.I tried to change it back to the original index by dropping the changedindex, and recreating the original index. I then ran the original query -which now went from 5 seconds to 36 seconds.I then ran DBCC REINDEX on that table. Performance of the query was stillmarkedly worse. I then reran the DBCC REINDEX on all tables, and then Iupdated each tables statistics. Performance of that query has never returnedto the original 5 seconds.What could be at issue here? Is there something else that I caused inchanging the index and changing it back?Ideas much appreciated.
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Dec 16, 2004
Pls tell me where i will be able to find a good material on interpreting the Execution plans................how do i compare 2 diff plans for Quries written in 2 diff ways...giving same output
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Jan 13, 2004
In using ADO to connect to SQL Server, I'm trying to retrieve multiple datasets AND statistics that are usually returned via the OnInfoMessage event. For those that are familiar with SQL Server, I need the results returned by the SET STATISTICS IO ON and SET STATISTICS PROFILE ON options. Anyone had any luck doing this before?
Thanks in advance.
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Jul 23, 2005
Hi there - hoping someone can help me here!I have a database that has been underperforming on a number of queriesrecently - in a test environment they take only a few seconds, but onthe live data they take up to a minute or so to run. This is using thesame data.Every evening a copy of the live data is copied to a backup 'snapshot'database on the same server and also, on this copy the queries onlytake a second or so to run. (This is testing through the QueryAnalyser)I've studied the execution plans for the same query on the snapshot dband the live db and they seem to be significantly different - why isthis? it's looking at the same data and exactly the same code!!Anybody got any ideas???
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Jan 26, 2007
Hi, just wondering if anyone noticed the MSSQL Express 2005 is so inconsistent with its performance. I was testing out a query with 2 joins, with the main table having about 13,600,000 records. With the same criteria value, sometimes it finished executing in 3 secs. sometimes almost a 1 min.
Could it be just the volume of the data? This is really driving me crazy!
Any advise will be greatly appreciated.
Rick..
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Dec 5, 2007
I have a query that joins two large partitioned tables and depending on the values in the where clause, I can get dramatically different performance results.
The first query completed in around 7s and has 47,000 logical reads.
select mo.monitor_id,
mo.site_id,
mo.testtime,
sum(mo.NumBytes),
sum(mo.DNSTime),
sum(mo.ConnectTime),
sum(mo.FirstByteTime),
sum(mo.ContentTime),
sum(mo.RelocTime)
from monitor_raw mr(nolock), monitor_object mo(nolock)
where mr.monitor_id in (5339, 5341, 5342, 943842, 943866)
and mr.testtime between 'Oct 31 2007 3:00:00:000PM' and 'Nov 30 2007 3:00:00:000PM'
and mo.returncode = 200
and mr.site_id in (101,102,105,109,110,112,115,117,119,122,126,151,132,139,129,135,121,138,143,142,159,148,128,171,176,177,178,111,113,116,118,120,127,133,131,130,174,179,185,205,200,202,203,204,210,211,208,209,212,213,216,199,214,224,225,229,230,232,235,241,245,247,250,254,261,267,264,265,266,268,269)
and mr.escalationlevel = 0
and mr.monitor_id = mo.monitor_id
and mr.testtime = mo.testtime
and mr.site_id = mo.site_id group by mo.monitor_id, mo.site_id, mo.testtime
The second query takes 188s to complete and has 1.8m logical reads. The only difference between the two is the value of the monitor_ids in the where clause.
select mo.monitor_id,
mo.site_id,
mo.testtime,
sum(mo.NumBytes),
sum(mo.DNSTime),
sum(mo.ConnectTime),
sum(mo.FirstByteTime),
sum(mo.ContentTime),
sum(mo.RelocTime)
from monitor_raw mr(nolock), monitor_object mo(nolock)
where mr.monitor_id in (152682, 5339, 5341, 5342, 268080)
and mr.testtime between 'Oct 31 2007 3:00:00:000PM' and 'Nov 30 2007 3:00:00:000PM'
and mo.returncode = 200
and mr.site_id in (101,102,105,109,110,112,115,117,119,122,126,151,132,139,129,135,121,138,143,142,159,148,128,171,176,177,178,111,113,116,118,120,127,133,131,130,174,179,185,205,200,202,203,204,210,211,208,209,212,213,216,199,214,224,225,229,230,232,235,241,245,247,250,254,261,267,264,265,266,268,269)
and mr.escalationlevel = 0
and mr.monitor_id = mo.monitor_id
and mr.testtime = mo.testtime
and mr.site_id = mo.site_id group by mo.monitor_id, mo.site_id, mo.testtime
The two tables have clustered indexes on monitor_id, testtime and site_id. Comparing the execution plan, I can see why there is such a difference in performance. The second query performs a clustered index seek on the monitor_object table starting at the lowest monitor_id, testtime & site_id through the highest monitor_id, testtime & site_id. The first query performs a clustered index seek where the monitor_id, testtime and site_id equals the same values from the monitor_raw table.
My question is, how can I force the second query to use the same execution plan as the first so that I can get better performance?
One possible workaround that I could use is to execute five individual queries, one for each monitor_id and then union the results together but this would require significant code changes to my stored procs.
Thanks,
Tim
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Feb 21, 2013
I think not. Microsoft says it is possible: one for parallel and one for serial execution. Don't believe that's possible for a stored procedure to change execution plans on the fly. Have an on-going problem with timeout occurring with an application and narrowed the culprit to a stored procedure. I couldn't find any obvious issues database wise, no locks, etc. so I recompiled (altered) the sproc without making any changes and the issue cleared for a couple days.
It happened again to day, and so I recompiled (altered) the sproc and it went away again. No code changes to both application (so they say) and stored procedure. I ran the below code snippet to check for sprocs with multiple cached plans and the offending one came up on a short list. So, my question is, Is it one sproc per query plan or can there be more than one. I understand the connection issues.
Code:
SELECT db_name(st.dbid) DBName,
object_schema_name(st.objectid, dbid) SchemaName,
object_name(st.objectid, dbid) StoredProcedure,
MAX(cp.usecounts) Execution_count,
st.text [Plan_Text]
INTO #TMP
[Code] .....
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Apr 16, 2008
Anyone know why using
SELECT *
FROM a LEFT OUTER JOIN b
ON a.id = b.id
instead of
SELECT *
FROM a LEFT JOIN b
ON a.id = b.id
generates a different execution plan?
My query is more complex, but when I change "LEFT OUTER JOIN" to "LEFT JOIN" I get a different execution plan, which is absolutely baffling me! Especially considering everything I know and was able to research essentially said the "OUTER" is implied in "LEFT JOIN".
Any enlightenment is very appreciated.
Thanks
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Apr 16, 2007
Hi,
We have a process that builds our data warehouse.
The processes execute SPs in serial order.
Each SP builds separate table.
Each table is build destructive (truncate and Insert Into).
I've tried to change the configuration by running 4 SP in parallel by SSIS to shorten the update time.
I've noticed in two declines in performance:
1. Each SP execution time is higher in the parallel execution in around 50% then in the serial execution. The CPU utilization is the same.
2. On each parallel execution we have a decline in performance of around 5 -10% compare to the previous parallel execution.
Do you have any directions to inquire?
Btw €“ we have Itanium 64bit x8 with 32GB memory
Thanks,
Assaf
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Mar 31, 2008
I am using SQL2005 EE with SP1. The server OS is windows 2K3 sp2
I have a table-valued function (E.g. findAllCustomer(Name varchar(100), gender varchar(1)) to join some tables and find out the result set base the the input parameters.
I have created indexes for the related joinning tables.
I would like to check the performance of a table-valued function and optimize the indexing columns by the execution plan.
I found the graphic explanation only show 1 icon to represent the function performance. I cannot find any further detail of the function. (E.g. using which index in joinning)
If I change the function to stored procedure, I can know whether the T-SQL is using index seek or table scan. I also found the stored procedure version subtree cost is much grether that the table-valued function
I would like to know any configureation in management studio can give more inform for the function performance?
Thanks
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Jul 27, 2015
For example in a Select Statement we have many tables and we have Where Clause with many conditions with AND operations. Do the SQL SERVER would apply the Where clause after all fetch or can dynamically decide about to include the related Tables from Select Statement Orderly with respect to where clause predicates? (SQL SERVER would not fetch data of those tables for its Select, where the AND condition in Where clause fails or by logic would be fruitless/not-related.)
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Aug 23, 2007
after moving off VS debugger and into management studio to exercise our SQLCLR sp, we notice that the 2nd execution gets an error suggesting that our static SqlCommand object is getting reused from the 1st execution (of the sp under mgt studio). If this is expected behavior, we have no problem limiting our statics to only completely reusable objects but would first like to know if this is expected? Is the fact that debugger doesnt show this behavior also expected?
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Feb 11, 1999
I need some advise on how to check the consistensy of a DateTime attribute.
Some of my Datetime field(s) won't read as a NULL and some does for example:
Select FileNo,DateReceived,DateEntered,DateFU from RECEIVING
where DateReceived is not null and DateEntered is not null and DateFU is not null
I should get several records but the result is zero.
Is there any articles out there about DateTime ?
I appreciate any help.
Thanks
Rey Caunca
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Apr 11, 2006
HiI have an oddity. If I run a piece of SQL:SELECT EmployeeNo, MailToFROM ST_PPS.dbo.Employeewhere AddedOn BETWEEN '01-jan-2006' and '01-feb-2006'AND MailTo NOT IN ( '3', 'x')order by MailToI get the resultsEmployeeNo MailTo----------- ------608384 1606135 1608689 1609095 1607163 1606165 1606472 1608758 1.....for 2594 rowsIf I create a stored procedure with the same SQL:-CREATE PROCEDURE dbo.PPS_testASSELECT EmployeeNo, MailToFROM ST_PPS.dbo.Employeewhere AddedOn BETWEEN '01-jan-2006' and '01-feb-2006'AND MailTo NOT IN ( '3', 'x')order by MailToGOand run it:-EXEC PPS_testI get three extra rowsEmployeeNo MailTo----------- ------607922 NULL606481 NULL605599 NULL606316 1608871 1607427 1608795 1.....for 2597Does anyone know what is happening here? It appears that the clause:-MailTo NOT IN ( '3', 'x')excludes NULL in raw SQL, but includes NULL (correctly I think) in astored procedure.Chloe CrowderThe British Library
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Jul 20, 2005
I get an error every so often with a DTS package on SQL 7. Error asfollows.The connection is currently being used by a task. The connectioncannot beclosed or re-used.This doesn't happen all the time and I can sometimes (more often thannot) get the DTS package to complete in it's entirety.To explain what the DTS package does...Truncate tables in reporting environment(several in a batch)Clear Transaction LogsCopies data from live environment into CSV (for speed)Copies data from CSV files into tables previously truncated.Builds up a table based on the data copied (for reporting)Clear Transaction logsI'm using a pretty basic set up, Connection (1st DB) -> Transformationto CSV -> Transformation to Connection (2nd DB). It seems to fail oneither the first or second transformation at random (?).I've checked the transformations so that they close the connectionafterwards so it should in theory be releasing the CSV files for thenext step. I suspect that there is a timing issue with this. I cancopy the CSV files over, but this is a little sloppy and I wouldprefer not to do it.Any ideas how to find a tidy way to ensure these are closed bothbefore and afterwards ?ThanksRyan
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May 5, 2008
Hi,
I am building a report with a recursive hierarchy for drill-down purposes. The hierarchy is built by querying a SSAS OLAP cube and defining a details grouping for the table/matrix.
Every time I run the report one or more of the leaf members in the recursive hierarchy "jumps" up to the highest level. First I thought that this may be due to the fact that the leafs parents are not part of the returned dataset. However, the queries makes sense and the "offending" members does never contain any data (while the query should return only non empty members) which is why this is a very strange behavior. Furthermore, the "offending" member differs between different executions of the report, despite the fact that the parameters is exactly the same and the cube is untouched between executions.
I am actually pressing "View Report", waiting for the report to execute and when I press "View Report" again, the returned datasets seem to differ, yielding different "offending" members in the report.
When I run the queries individually in the Data-tab in BIDS, the returned datasets are always the same. Execution caching is turned off for the report.
Checking against SSRS's ExecutionLog, the RowCount for consecutive executions with the exact same parameters differ. For example, RowCount:
3094
3080
3079
3088
3087
Why does SSRS behave such inconsistently? Any tips or tricks?
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Apr 10, 2001
I am running SQL Server 7.0 on NT 4.0. I have created a simple query:
SELECT SUM(month1) As total_month1
FROM eac_manload
WHERE project_number = 8800
and dept IN (50,51,52,55,57,60,61,62,63,64,65,68,69)
I first time I run the query I get the correct result. Subsequent times that I run the query the result is 1 record with a Null value. The data has not changed. If I stop MSSQLSERVER and restart the service I get the correct result the first time and the Null value each time thereafter. Anybody out there with any idea of what is going on here? Any help will be appreciated!!
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Mar 2, 1999
I apologize for the length of this message, but I think I need to include all this info so that the problem is understood. I am having what appears to be a problem capturing the return code from a failed BCP.
I create a stored proc to use BCP to load a table:
create procedure sp_bcp_load as
declare @RC int
execute @RC = master..xp_cmdshell "bcp JON..W4KPV in e:inetpubftprootfinreslaw4kpv.g4000.data /Sdbmtss1 /m 0 /f d:mssqluserdatafinresW4KPV.fmt /Usa /P /e d:mssqluserdatafinrescp1.err /t""|"" /r "
select 'Return code from bcp = ', @RC
if @RC <> 0
BEGIN
print 'BCP Error.'
return (8)
END
GO
If I execute the SP, and encounter a transaction log full error, the return code is still zero:
1000 rows sent to SQL Server. 45000 total
1000 rows sent to SQL Server. 46000 total
Msg 1105, Level 17, State 2:
Server 'DBMTSS1', Line 1:
Can't allocate space for object 'Syslogs' in database 'Jon' because
the 'logsegment' segment is full. If you ran out of space in Syslogs,
dump the transaction log. Otherwise, use ALTER DATABASE or sp_extendsegment to increase the size of the segment.
(54 row(s) affected)
----------------------- -----------
Return code from bcp = 0
If I execute the SP again, it correctly returns a non-zero value:
Msg 1105, Level 17, State 2:
Server 'DBMTSS1', Line 1:
Can't allocate space for object 'Syslogs' in database 'Jon' because
the 'logsegment' segment is full. If you ran out of space in Syslogs, dump the transaction log. Otherwise, use ALTER DATABASE or sp_extendsegment to increase the size of the segment.
(6 row(s) affected)
----------------------- -----------
Return code from bcp = 1
(1 row(s) affected)
BCP Error.
Does anybody have an idea why this behaves this way? Any suggestions on how to trap an error on the first call?
Thanks,
Jon Carter
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Jan 11, 2008
Hello all-
Maybe someone has some insight on this... I currently have some hash values (SHA512 through Enterprise Library) that I'm trying to compare to data in our database. When I sort the values on the pipeline (DT_STR, 1252) with a Sort and compare them against values coming out of an OLE DB Source (SQL_Latin_1_General_CP1_CI_AS) with a Merge Join, any hash that has a '/' in it is treated as inequal to the one in the database.
For even more fun, when I change the sort/merge join to a Lookup, everything (seems) to check out. Is the 1252 code page not the same as SQL_Latin_1_General_CP1_CI_AS? Any other reasons this might be happening?
Cheers,
-Brandon Tucker
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