I have a problem in SQL Server 2005. In some cases SQL Server produces an execution plan of complex query (8 joins of views, some of views contains couple of joins) which does not contain a woktable creation in tempdb. As a result time of query execution increasion for about 5 seconds to about 4 minutes. All necessary indexes are created. It sims all data located in cache. Is there any way to enforce SQL Server to create worktable?
Query
SELECT [a0].[id],[a0].[Priority],[a0].[Heading],[a0].[DocumentDate],[a0].[LastName],[a0].[FirstName],[a2].[Name],[a1].[Position],[a4].[ContactTime],[a4].[Subject],[a0].[WorkPhone],[a0].[MobilePhone],[a0].[FaxNumber],[a0].[PrimaryEmail],[a5].[ContactTime],[a6].[Value],[a7].[id],[a7].[id_class],[a8].[id],[a8].[id_class],[a0].[FIO]
FROM [Bkc_EBM_Person_View] [a0]
LEFT JOIN [Bkc_EBM_ContactsInfo_View] [a3] ON ( a0.ContactsInfo_id = a3.[id] )
LEFT JOIN [Bkc_EBM_Contact_View] [a4] ON ( a3.LastContact_id = a4.[id] )
LEFT JOIN [Bkc_EBM_Contact_View] [a5] ON ( a3.NextContact_id = a5.[id] )
LEFT JOIN [Bkc_EBM_PersonType_View] [a6] ON ( a0.PersonType_id = a6.[id] )
LEFT JOIN [Bkc_EBM_Employment_View] [a1] ON ( a0.PrimaryEmployment_id = a1.[id] )
LEFT JOIN [Bkc_EBM_Client_View] [a2] ON ( a1.Client_id = a2.[id] )
LEFT JOIN [Bkc_EBM_Person_View] [a7] ON ( a0.Responsible_id = a7.[id] )
LEFT JOIN [Bkc_EBM_Department_View] [a8] ON ( a0.Department_id = a8.[id] )
Statistics
(2454 row(s) affected)
Table 'ReadRights'. Scan count 2455, logical reads 109411, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'ProcessAccounts'. Scan count 11102, logical reads 22266, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Bkc_EBM_Department'. Scan count 0, logical reads 4908, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Bkc_EBM_Person'. Scan count 0, logical reads 38986, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Bkc_EBM_Client'. Scan count 0, logical reads 4826, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Bkc_EBM_Employment'. Scan count 0, logical reads 83632238, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Bkc_EBM_PersonType'. Scan count 0, logical reads 4908, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Bkc_EBM_Contact'. Scan count 0, logical reads 9816, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Bkc_EBM_ContactsInfo'. Scan count 0, logical reads 4908, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
(1 row(s) affected)
SQL Server Execution Times:
CPU time = 231719 ms,elapsed time = 253491 ms.
Execution plan
http://rsdn.ru/File/22090/plan1.rar
Please post the view definitions.
It looks like your view definition for BKc_EBM_Employment has a bad join in it, You are processing 640Gb of data from the BKcEBM_Employment table
|||try forcing a recompile.
e.g.
select *
from ...
option (recompile)|||
Below is the view definition
Bkc_EBM_Employment is a table which connects Bkc_EBM_Person and Bkc_EBM_Client in a many-to-many relation.
ReadRights is a table which defines rights of user account to view particular document in system
processaccounts is a table, to which Application server writes corrspondence between current spid and user account id, before executing a query
USE [Oblik_CRM]
GO
/****** Object: View [dbo].[Bkc_EBM_Employment_View] Script Date: 10/04/2006 10:18:38 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE VIEW [dbo].[Bkc_EBM_Employment_View] WITH SCHEMABINDING AS
(SELECT [id], 1370 AS [id_class], cast([id] as varchar(64))+'_1370' AS [id_record], t.[EmployedPerson_id], t.[EmployedPerson_class_id], t.[Client_id], t.[Client_class_id], t.[Department_id], t.[Department_class_id], t.[Position], t.[PlaceOfWorkType_id], t.[PlaceOfWorkType_class_id], t.[RoleEmployee_id], t.[RoleEmployee_class_id], t.[FRC_id], t.[FRC_class_id], t.[InnerPhone], t.[IsPrimary], t.[IsFired], t.[EmploymentDate], t.[FiredDate], t.[FiredReason_id], t.[FiredReason_class_id], t.[Description], t.[RightToSign], t.[Heading], t.[Version] FROM dbo.Bkc_EBM_Employment t
inner join dbo.ReadRights r on (t.EmployedPerson_id = r.object_id) inner join dbo.ProcessAccounts pa WITH (NOLOCK) on (r.account_id = pa.account_id) where pa.spid=@.@.spid
)
|||
I rewrite the query without using viws. It helps a little because in new query data, that not needed by this query not queried by the views. But time of query execution is still to long. About 2 minutes
declare @.userID int
set @.userID = 104356
declare @.qp_0 int
set @.qp_0 = 0
DELETE ProcessAccounts WITH (ROWLOCK) WHERE spid=@.@.spid INSERT ProcessAccounts WITH (ROWLOCK) (account_id, spid) VALUES (@.userID, @.@.spid)
SELECT
[a0].[id],[a0].[Heading],[a0].[DocumentDate],[a0].[DocumentId],[a0].[Name],[a0].[PrimaryPhone],[a0].[PrimaryEmail],
[a1].[FIO],
[a3].[ContactTime],
[a4].[WorkPhone],[a4].[WorkEmail],[a4].[FIO],
[a5].[Value],
[a6].[Position],
[a7].[ContactTime]
FROM
(
SELECT [a0].[id],[a0].[Heading],[a0].[DocumentDate],[a0].[DocumentId],[a0].[Name],[a0].[PrimaryPhone],[a0].[PrimaryEmail], a0.Responsible_id, a0.ClientType_id, a0.ContactsInfo_id, a0.IsTemplate FROM [Bkc_EBM_Client] [a0]
INNER JOIN [ReadRights] [a0r] ON ([a0].[id] = [a0r].[object_id] )
INNER JOIN ( SELECT [account_id] FROM [ProcessAccounts] WITH (NOLOCK) WHERE [spid] = @.@.SPID ) [a0pa] ON ( [a0r].[account_id] = [a0pa].[account_id] )
) [a0]
LEFT JOIN [Bkc_EBM_ClientType] [a5] ON ( a0.ClientType_id = a5.[id] )
LEFT JOIN
(
SELECT [a1].[id], [a1].[FIO] FROM [Bkc_EBM_Person] [a1]
INNER JOIN [ReadRights] [a1r] ON ([a1].[id] = [a1r].[object_id] )
INNER JOIN ( SELECT [account_id] FROM [ProcessAccounts] WITH (NOLOCK) WHERE [spid] = @.@.SPID ) [a1pa] ON ( [a1r].[account_id] = [a1pa].[account_id] )
) [a1] ON ( a0.Responsible_id = a1.[id] )
LEFT JOIN [Bkc_EBM_ContactsInfo] [a2] ON ( a0.ContactsInfo_id = a2.[id] )
LEFT JOIN
(
SELECT [a3].[id], [a3].[ContactTime] FROM [Bkc_EBM_Contact] [a3]
INNER JOIN [ReadRights] [a3r] ON ([a3].[id] = [a3r].[object_id] )
INNER JOIN ( SELECT [account_id] FROM [ProcessAccounts] WITH (NOLOCK) WHERE [spid] = @.@.SPID ) [a3pa] ON ( [a3r].[account_id] = [a3pa].[account_id] )
) [a3] ON ( a2.LastContact_id = a3.[id] )
LEFT JOIN
(
SELECT [a4].[id], [a4].[WorkPhone],[a4].[WorkEmail],[a4].[FIO], [a4].[PrimaryEmployment_id] FROM [Bkc_EBM_Person] [a4]
INNER JOIN [ReadRights] [a4r] ON ([a4].[id] = [a4r].[object_id] )
INNER JOIN ( SELECT [account_id] FROM [ProcessAccounts] WITH (NOLOCK) WHERE [spid] = @.@.SPID ) [a4pa] ON ( [a4r].[account_id] = [a4pa].[account_id] )
) [a4] ON ( a2.LastContactPerson_id = a4.[id] )
LEFT JOIN
(
SELECT [a6].[id], [a6].[Position] FROM [Bkc_EBM_Employment] [a6]
INNER JOIN [ReadRights] [a6r] ON ([a6].[EmployedPerson_id] = [a6r].[object_id] )
INNER JOIN ( SELECT [account_id] FROM [ProcessAccounts] WITH (NOLOCK) WHERE [spid] = @.@.SPID ) [a6pa] ON ( [a6r].[account_id] = [a6pa].[account_id] )
) [a6] ON ( a4.PrimaryEmployment_id = a6.[id] )
LEFT JOIN
(
SELECT [a7].[id], [a7].[ContactTime] FROM [Bkc_EBM_Contact] [a7]
INNER JOIN [ReadRights] [a7r] ON ([a7].[id] = [a7r].[object_id] )
INNER JOIN ( SELECT [account_id] FROM [ProcessAccounts] WITH (NOLOCK) WHERE [spid] = @.@.SPID ) [a7pa] ON ( [a7r].[account_id] = [a7pa].[account_id] )
) [a7] ON ( a2.NextContact_id = a7.[id] )
WHERE ([a0].[IsTemplate] = @.qp_0 OR [a0].[IsTemplate] IS NULL )
DELETE ProcessAccounts WITH (ROWLOCK) WHERE spid=@.@.spid
Statistics
(1750 row(s) affected)
Table 'ReadRights'. Scan count 5891, logical reads 222578, physical reads 425, read-ahead reads 283, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'ProcessAccounts'. Scan count 6, logical reads 5891, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Bkc_EBM_Contact'. Scan count 0, logical reads 7000, physical reads 98, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Bkc_EBM_Employment'. Scan count 0, logical reads 33686288, physical reads 33, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Bkc_EBM_Person'. Scan count 0, logical reads 7000, physical reads 60, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Bkc_EBM_ContactsInfo_View'. Scan count 0, logical reads 3500, physical reads 5, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Bkc_EBM_ClientType_View'. Scan count 0, logical reads 3500, physical reads 1, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Bkc_EBM_Client'. Scan count 0, logical reads 33252, physical reads 43, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
(1 row(s) affected)
SQL Server Execution Times:
CPU time = 111797 ms, elapsed time = 123889 ms.
Execution Plan
http://rsdn.ru/File/22090/plan4.rar
|||
Please post the scripts for all the tables involved and indexes.
To get performance you need to reduce the amount of data being read from Bkc_EBM_Employment
|||Do you have a where clause on your query ?|||
 SimonS_ wrote: |
|
| Do you have a where clause on your query ? |
Yes "WHERE ([a0].[IsTemplate] = @.qp_0 OR [a0].[IsTemplate] IS NULL ) " (see query in the answer above) but there is no records in database filtered by this condition.
About database
'ReadRights' ~ 500000 records
'ProcessAccounts' 1 record
'Bkc_EBM_Person' ~ 2500 records
'Bkc_EBM_Client' ~ 1700 records
'Bkc_EBM_ClientType' ~ 20 records
'Bkc_EBM_ContactsInfo' ~ 4000 records
'Bkc_EBM_Contact' ~ 5000 records
'Bkc_EBM_Employment' ~ 2500 records
Very strange, but it sims RECOMPILE option helps. Worktable is created even right after SQL Server restart. If RECOMPLIE not used after server restart Worktable not created.
|||
The problem is query plans. Your query won't change from one user to the next or from one template to the next however this means the same query plan will be used. However the same query plan will not be optimal for all situations.
What can happen is that a plan is put in the cache based on the first set of parameters supplied, if this plan is not suitable for all queries you can end up with the problem above.
The recompile will address this at the expense of having to compile the query every time.
|||
Thank you for your help Simon. RECOMPILE is really helps.
Maybe in my case using of parameters in a query is not the best choise? Especially @.userID ?
|||Can you still post the CREATE table statements and CREATE View statements so I can understand your query better, its quite difficult with your use of views to understand what is joining to what.|||
Script will be quite large. Maybe by email?
|||try SQLForumsATonarcDOTcom|||I send the script. Please check.|||Another problem. In SQL Server 2000 option (recompile) is not supported. Is there any way to enforce SQL Server 2000 to recompile execution plan every time?
