I have been trying to the query optimizer to generate a parallel execution plan but no matter the MaxDOP (0) or Cost Threshold (5) settings I use it will only execute in serial.
UPDATE [dbo].[Targus_201412_V7_B]
SET [URBAN] =(
CASE
WHEN [METRO_STATUS] = 'Urban' THEN 1
ELSE 0
END)
if t-sql query is perfectly run in development and when I execute in production at that time I want to use execution plan which is in development . so how I can do using cache? I know about hint we can use hint USE_PLANE. but I want to do with cache .
View 1 Replies View RelatedThe benefit of the actual execution plan is that you can see the actual number of rows passing through each step - compared to the estimated number of rows.But what about the "cost percentages" ?I believe I've read somewhere that these percentages is still just an estimate and is not based on the real execution.Does anyone know this and preferable have a link to something that documents it?Thanks
View 1 Replies View RelatedHi
View 5 Replies View RelatedIs there any way to run a stored procedure in parallel to another one? i.e. I have a stored procedure that sends an email. I then scan a table and send any unsent emails. I do not want the second part to slow the response to the user.
View 2 Replies View RelatedI'd like to run 4 stored procedures in parallel on 4 different processors on our server.
Does anyone know the syntax to do that? (Could not find it on the web so far).
Anything else I need to do in addition to the specific syntax (i.e. any specific properties to set in Enterprise Manager)?
Your help is greatly appreciated!
Lana
I’ve been looking at a bug in an application stored proc. This merely inserts 7 million rows from one table into another (empty) table.
INSERTÂ
dbo.TradeDataPrimary
(Id, SinaiTrade)Â
SELECTÂ
ts.Id,
CAST(ts.XmlTrade
AS varbinary(MAX))
FROM dbo.TradePrimary ts
Both tables have a clustered index with the same key order (on the first column) but the query optimizer insisted on placing a SORT step in the query plan. This use a lot of tempdb which I wanted to avoid.
I discovered that the bug was a data type mismatch. Fixing the bug and/or dropping the clustered index from the target table before the insert resulted in the plan I expected, that is, with no sort.
I was hoping it would run faster but, unfortunately, as can be seen from the new plan below, a serial plan is used. This results in the insert taking nearly three times as long as the original.
I’ve been looking at Paul White’s article: [URL] ....
and Adam Machanic’s: [URL] ....
Both are excellent articles but neither approaches i.e. trace flag 8649 or make_parallel () give me a parallel plan. Am I missing a trick here? How I can force parallelism? I know there are no features that require a serial zone in the plan otherwise the plan with the sort would not be parallel..
This is SQL Server 2012 Enterprise 11.0.5522.0, 512 GB of RAM and 16 procs.
We have a monitoring tool that find a query that is using most of execution time of all sessions on the server.
I located it, and found it is a data flow task in an SSIS package.
It export data from a table which has big mount of data to another database.
I know it only executes one time, but I see in the monitoring tool it executes 4 times.
I am wondering is it because SSIS is doing it in parallel execution automatically?
We use all default settings, and the server physical cpu is 4.
Also it says the query is slow is because it has a wait called PREEMPTIVE_OS_WAITFORSINGLEOBJECT
not sure what does that mean
I have another post here regarding SQL 2005 running a query 50% slower than on 2000. It was discovered that 2005 runs the query in series whereas 2000 runs it in parallel.
Even with "Cost Threshold For Parallelism" set to a default value – 0, 2005 still executes my query in series. Does anyone know how to force a query to run in parallel in SQL 2005. I specifically want to set it at the database level.
I have a SQL 7 db with a union query (view), and I'm getting the error, "Thequery processor could not start the necessary thread resources for parallelquery execution." This union query has been in place for about two years nowwith no problems until just now, though I haven't changed anything. Also, Ihave a local copy of the database on my machine, and the query runs fine.As noted, I haven't changed anything in the query, nor in the SQL settings.There is a network administrator, so it's possible that he may have changeda setting, but I don't know what. The query is reproduced below. Any ideasas to what's going on would be appreciated.NeilMain query:SELECT Tmp.INVCUST, Tmp.SDNBR, Tmp.SDBOOK, Tmp.SDIVCLN,Tmp.SDPAID, Tmp.SDPRICE, Tmp.SDCOPIES, Tmp.Location,INVTRY.AUTHILL1, Tmp.INVDATE, INVTRY.SaleSrc,INVTRY.HoldInitFROM (SELECT INVDATE, INVCUST, SDNBR, SDBOOK, SDIVCLN,SDPAID, SDPRICE, SDCOPIES, 'P' AS LocationFROM vwInvoiceDetUNION ALLSELECT INVDATE, INVCUST, SDNBR, SDBOOK, SDIVCLN,SDPAID, SDPRICE, SDCOPIES, 'N' AS LocationFROM vwInvoiceDetNUNION ALLSELECT INVDATE, INVCUST, SDNBR, SDBOOK, SDIVCLN,SDPAID, SDPRICE, SDCOPIES, 'M' AS LocationFROM vwInvoiceDetM) Tmp INNER JOINdbo.INVTRY ON Tmp.SDBOOK = dbo.INVTRY.[Index]vwInvoiceDet:SELECT tabInvoice.INVDATE, tabInvoice.INVCUST,SALEDET.SDNBR, SALEDET.SDBOOK, SALEDET.SDINVNUM,SALEDET.SDPRICE, SALEDET.SDPAID, SALEDET.SDCOPIES,SALEDET.SDIVCLN, tabInvoice.INVNBR, SALEDET.SDIDFROM dbo.tabInvoice INNER JOINdbo.SALEDET ONdbo.tabInvoice.INVNBR = dbo.SALEDET.SDNBR(vwInvoiceDetN and vwInvoiceDetM are similar to vwInvoiceDet.)
View 2 Replies View RelatedHi,
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
Is is possible to get the iterations in a foreach loop to run in parallel? What I need to do is to spawn an arbitrary number of parallel execution paths that all look exactly the same. The number is equal to the number of input files, which varies from time to time. Any help is appreciated!
View 27 Replies View RelatedHi,
we're accessing a SQL Server as a source for some SSIS packages using quite complex SQL commands. We have dataflows getting data from up to 10 queries. The problem is that SSIS starts all these queries in parallel using up all the memory of the server (the source SQL server, not the server SSIS is running on). So the queries are very slow. Is there any way to force SSIS to start the queries after each other?
I already browsed the web for some answers on that and I'm not very optimistic... Maybe the only solution is really to feed the result of the query in raw files and process them later...
Thanks,
I have a scenario where i have to run update task on multiple servers in parallel and once all of them are completed (success or failure) another task is to be run on another server
1. in maintenance plan, if we add tasks which are not joined, will they run in paralled at the same time
2. if we link the last task to all the tasks with link type 'completed' will the last task complete after all tasks are completed or when any one of them is completed (i have big doubt here)
the business requirement behind this is to bring data from multiple servers into shadow copies locally and then process them together. its ok if some server data transfer fails, but its not ok to start processing centrally while data transfer is going on. further, we want to run data transfer from multiple servers in paralleled to save time.
I've got an SSRS report that is set up using a data-driven subscription to supply input parameters to the stored procedure that is called to generate the report results.
I was wondering if there is any way to specify the execution processing method (running the reports in parallel or serially). The subscription that we have set up appears to be running all of the reports in parallel which is causing massive load on our servers.
Thanks.
I'm new to SQL server but familiar enough with databases to know this doesn't seem right.
Here's the situation:
I have a table with real estate property information. There are about 650,000 rows in it. I have a nonclustered non-unique index on the city where the property is located. There are about 40 unique values in this index.
I do a simple query like:
SELECT city,address from propinfo where city= 'CARLSBAD'. The query will return about 4,000 rows. The problem is that the execution plan that it chooses is to do a full table scan. I.E. Even though there is an index on City, it chooses to look through 650,000 rows rather than do an index seek. Something sounds inefficient here. BTW, this happens in both SQL 7 and SQL 2000. Can anyone explain why this happens? I've got to think that SQL Server is more efficient here.
Hello, I have been looking at the execution plan for a procedure call and the select, compute scalar, stream aggregates, constant scan, nested loops, asserts are all at 0% cost, the PK costs are 2% apart from a rogue 7% and a few 20%, tables scans are all at 23%. The query cost realtive to the batch is 100%. What does this all mean?
I have put non-clustered indexes on all the table attributes that are involved in the select statements but this has made no difference, i am guessing this is because my tables are not heavily populated and i may have seen a difference if i had thousands of entries in the tables the select statements acted on, is this assumption correct?
Does anyone else bother using the execution plan to tweak there DB or is it a negligible tool?
Jill
In sql server 2005 management studio where do I find the option to run the sql query in the query analyser and also show the execution plan?
At present I see the option under Query menu which is "Display estimated Execution plan" which only shows the plan but does not execute the query.
Thanks
Does anyone know of a good way to copy the execution plan when using "Include Actual Execution Plan"?
I often need to copy this and mail it.
I know I can use PrintScreen button, but I need a more efficient way to do this.
If I just could rightclick the execution plan and select "Copy" and get complete plan it would be great.
Mladen?
E 12°55'05.25"
N 56°04'39.16"
Which of the following does NOT cause the execution plan of a query to berecompiled ?- new column is added to a table accessed by a query OR- index used by a query has been dropped from the database OR- query perfoms a join to return data from multiple tables OR- significant amount of data in a table has been mofified
View 1 Replies View RelatedHi,I have a table-valued user defined function (UDF) my_fnc.The execution of statement "select * from my_fnc" takes much longertime than runnig the code inside my_fnc (with necessary changes).What can be the reason?How can I see an execution plan used for UDF?Thanks a lotMartin
View 1 Replies View RelatedSelect A.* from A inner join B on ( A.ID= B.ID )
I know there is some key word that you use to force SQL server to generate a new query plan ?What can that be ?
Hi,I want to access the real execution plan via my webapplication after I have executed an SQL statement. I know how to get the estimated execution plan:1 cmd.CommandText = "SET SHOWPLAN_XML ON";2 cmd.ExecuteNonQuery();3 4 cmd.CommandText = myStatement;5 SqlDataReader dataReader = cmd.ExecuteReader();6 7 String plan = String.Empty;8 9 while (dataReader.Read()) {10 plan += dataReader.GetSqlString(0).ToString();11 }12 13 cmd.CommandText = "SET SHOWPLAN_XML OFF";14 cmd.ExecuteNonQuery();I want do compare the estimated costs with the real costs of the same statement. If I change code line 1 an 13 to "SET STATISTICS XML [ON|OFF]" the string "plan" will contain the result of the submitted SELECT statement, but I just need to get the plan and not the result itself. Thanks in Advance,Dominik
View 6 Replies View RelatedWhat does 'tablename. index... cost: 100%' mean when I use display estimated execution plan?
View 1 Replies View RelatedHello ,
I wanted to know whether we have an execution plan enabled in SQL 6.5 as we have it in SQL 7.0 and SQL 2000 .
I.e when we execute a query and if we enable ' show execution plan 'then it creates a map and shows the vital statistics .
If that is available on SQL 6.5 then i am missing that tool .
How can i have it installed on my SQL 6.5 server ??
Thanks.
Hi,
I want to know how to analyze query execution plan for complex queries and what information is useful from that for improving the performance. I have gone through details in some sites like www.like sql-performance.com (http://www.sql-server-performance.com/query_execution_plan_analysis.asp), where it was more generic. I want more info regarding this.
Can any one tell about the resources for this or do you have any white papers or documents, which you can share with me.
Thanks in advance,
sekhar
Hi ,
when
operator = then index SEEK
operator <> then index SCAN
Is normal ?
Example
SELECT *
FROM dbo.Batch
WHERE (Status = 'Batch Completed')
(1 row(s) affected)
StmtText
---------------------------------------------------------------------------------------------------------------------------------
|--Bookmark Lookup(BOOKMARK:([Bmk1000]), OBJECT:([PriceAvisPr].[dbo].[Batch]))
|--Index Seek(OBJECT:([PriceAvisPr].[dbo].[Batch].[IX_Batch]), SEEK:([Batch].[Status]='Batch Completed') ORDERED FORWARD)
StmtText
---------------------------------------------------------------------------------
SELECT *
FROM dbo.Batch
WHERE (Status <> 'Batch Completed')
(1 row(s) affected)
StmtText
------------------------------------------------------------------------------------------------------------------------
|--Clustered Index Scan(OBJECT:([PriceAvisPr].[dbo].[Batch].[PK_Batch]), WHERE:([Batch].[Status]<>'Batch Completed'))
Hi all,
I am experiencing performance problems with one of my stored procedures. When the stored procedure is first compiled an executed, it behaves as expected (it usually takes 1 or 2 seconds to complete). But its performace it is degradated, so in 1 day, it usually takes 120 seconds to complete !!!. Once the stored procedure is compiled, its performance it is then the expected.
It is a complex stored procedure with two integer parameters with only one select, but composed by multiple views and sub-queries. We have been trying to break the query into small pieces using temporary tables but without success. The SQL Profiler shows an unusual number of reads when it goes wrong (more than a million reads).
I think the problem is in the execution plan. I know than compiling the stored procedure, the problem is fixed, but I do not know exactly when and why it starts to happen.
The stored procedure is running under the following configuration:
- Microsoft SQL Server Standard Edition (64-bit).
- Version: 9.00.1399.06
- RAM 16 MB
- 8 CPUs
Anyone has any ideas or possible solutions?
Thanks in advance,
Carlos.
The cost of query with usage of functions is as same as that of withoutfunctionsIn the below code, the query cost of insert is 0.02% and two selectstatements costs same 0.04%Declare @t table(mydate datetime)Declare @i intset @i=1while @i<=5000Begininsert into @t values(getdate())set @i=@i+1EndSelect mydate from @tSelect convert(varchar,mydate,112) from @tBut I thought usage of convert function will take more query costWhat do you think of this?Madhivanan
View 5 Replies View RelatedWe've got as slightly unusual scenario happening whereby a statement ispassed to SQL which consists of two parts.BEGIN TRANSACTIONDELETE * FROM WhateverBULK INSERT INTO Whatever...(etc)COMMIT TRANSACTIONThe first is a deletion of the data and the second is the bulk insertof replacement data into that table. The error that we see is aviolation of the primary key (composite).The violation only happens if we run both processes together. If we runone, then the other, it works fine. If we set a line by line insert, itworks fine.My suspicion is that the execution plan that is being run is mostlikely working the two parts in parallel and that the records stillexist at the point that the insert is happening. Truncate is not anoption. The bulk insert was added for performance reasons. There is anoption of trying the bulk insert, and if that fails, do the line byline insert, but it's far from ideal.I think we can probably wrap this into two individual transactionswithin the one statement as follows :BEGIN TRANSACTIONDELETE * FROM WhateverCOMMIT TRANSACTIONBEGIN TRANSACTIONBULK INSERT INTO Whatever...(etc)COMMIT TRANSACTIONWill this give sufficient hint to SQL about the order it processes itso that it completes as we intend and not as it sees being the mostefficient method ?Or, is there a better approach to this ?I've seen that some hints can be passed to SQL for optimizing, but myunderstanding was that it was always better to trust the optimiser andre-work the query as needed.With the server having two processors, is it feasible that one is doingone part and the other processor the other part in parallel ? Willtelling it to use a single processor be worthwhile looking at ? MAXDOP1 ?Finally, I'd imagine that the insert is quicker to process than thedeletion. Is this correct ?ThanksRyan
View 14 Replies View RelatedUsing SQL Server 2000 SP4.There is a relatively complex stored procedure that usually completes inless than 20 seconds. Occasionally it times out after 180 seconds. The SPis called via ADO 2.8, using adCmdStoredProc command type. If I useProfiler to capture the EXEC that ADO sends to run the procedure, and runthat from QA, the procedure completes in less than 20 seconds as it should.The procedure is created WITH RECOMPILE. One additional twist is thatsp_setapprole is called from the client before running the procedure inquestion. This may be irrelevant, because even if I include the samesp_setapprole call when running the procedure from QA, it still executesquickly, and even if I comment out the call to sp_setapprole in the clientcode, the proc still times out when run from the client.The only thing that fixes it, at least for a day or two, is DBCCFREEPROCCACHE. So it appears that a bad plan is somehow stuck in memory andis only used when the procedure is called from the client app, and is notflushed even though the procedure was created WITH RECOMPILE.Other than scheduling the DBCC call to run every night, is there anythingelse I could try to get this resolved? Thanks.--(remove a 9 to reply by email)
View 5 Replies View RelatedI was hoping someone could shed some light on wierd situation i'm experiencing. I have the following query:
select count(*) LeadCount
from auto_leads al
where received > dbo.GetDay(GetDate())
dbo.GetDay simply returns a smalldatetime value of today's date.
Now I recently got thrown into a data mess and for some reason this query takes 8 seconds to run. Now the first thing I did was update the stats on the Received column of this auto_leads table. I re-run the query and I'm still getting 8 seconds. I look at the execution plan I can make figure out why this is happening.
I then change the above query so the filter received > dbo.GetDay(GetDate()) is now just received > '5/31/2006' and the query comes back immediately. This doesn't make sense to me because the GetDay function is really simple and comes back immediately. I then try the following query to confirm it isn't a problem with the GetDay function:
declare @Today DateTime
set @Today = dbo.getday(GetDate())
select count(*) leads
from auto_leads al
join type_lead_status tls on (tls.type_lead_status_id = al.type_lead_status_id)
where received > @Today
Sure enough, the query came back immediately. Next thing to go through my mind is that the query execution plan has been cached by SQL Server using the execution plan from before I updated the stats on the received column. So I executed sp_recompile 'auto_leads' and tryed the original query again. Still taking 8-10 seconds to come back.
So my question, is why when I remove the GetDay function call in my query filter is the query slow, as opposed to me just passing a variable into the query? Thanks!
- James
I'm new to sql server 2005 and was reviewing the execution plan on one of my queries.
I have a query that selects about 62,000 rows from a table of about 20 million
I see there is a index seek indicated but further down the execution plan I see that a large percent is being assigned to a RID LOOKUP on the same table.
Should I be concerned with this and if so, what would you recommend I do to correct it?