Slow Running Query With A High Lob Logical Reads, Lob Data

Jun 1, 2007

we had some slow down complaints lately and this query seems to be the culprit almost every single time. The estimated execution plan is a clustered index seek as there is a clustered index on the uidcustomerid column. setting profile statistics on shows that every time it executes it does an index seek.

profiler session showed a huge number of reads for these queries depending on the value being looked up. 1500 through 50000. i set up profile io on and the culprit is lob logical reads. everything else is 0 or very low. in this case lob logical reads is over 1700.

3 of the columns in the select statement are text columns. when i take them out of the query the lob logical reads drops to 0 and goes up incrementally as i add each column back in.

is there anyway to improve the performance without changing data types to varchar(max)?


select SID,Last_name,Name_2,First_name,Middle_initial,Descriptives,Telephone_number,mainline,Residence,ADL,
DID_number,Svce_street,Svce_town,Svce_state,Svce_appt,Mailing_street,Mailing_town,Mailing_state,Mailing_appt,
Mailing_zip,Listing,Addl_listing,Published,Listed,Gold_number,PIN,status,SSnumber,tax_jurisdiction,
Bill_date,Past_balance,Service_start_date,Service_end_date,LOA,FCC_type,Line_type,I_W,Jacks,Voice_messaging,
vms_ring_cycles,CCS,phonesmarts,ringmate,voice_dialing,Bill_detail,Contact_Number,Contact_extension,
Best_Time,suspend,suspend_start,suspend_end,credits_allowed,credits_granted,home_region,Calling_Plan,Local_Plan,
Local_Plan_Rate,Flat_Rate,Sales_agent,Community,Building_Mgmt,How_Heard,Incentive_1,Incentive_1a,Incentive_1b,
Incentive_1c,Incentive_2,Incentive_2a,Incentive_2b,Incentive_2c,Incentive_3,Incentive_3a,Incentive_3b,
Incentive_3c,block_operator,block_collect,block_group,block_adult,block_call_return,block_repeat_dialing,
block_call_trace,block_caller_id,block_anonymous,block_all_high_toll,block_regional_and_ld,block_DA_Call_Completion,
block_DA,block_3rd_party,bank,prepayment,dial_around_number,custid,waive_interest,Financial_Treatment,
Other_Feature_1_code,Other_Feature_1_rate,Other_Feature_2_code,Other_Feature_2_rate,Other_Feature_3_code,
Other_Feature_3_rate,Other_Feature_4_code,Other_Feature_4_rate,Partial_Account,mail_date,snp_1_date,snp_2_date,
terminate_date,snp1notified,snp1peak,snp1offpeak,snp2notified,snp2peak,snp2offpeak,avg_days_paid,Pulled_Ld,SNP1,
SNP2,Treatment,Collections,Installment,Nynex_BTN,LD_rate,local_discount,to_month,rounds_up,full_package_made,
local_made,PIC,LPIC,tax_exempt_local,tax_exempt_federal,CommissionedAgent,LDRateID,UidCustomerId,
accVchLineClassUSOC,block_Inter_Reg_LD,block_international,block_DA_3rd_Collect,block_DH2,block_ISP_2,block_ISP_3,
block_ISP4_3_GBAS,block_ISP3_3_GBAS,block_collect_only,block_LD_Reg_DA,block_usage_based,block_ISP5_3_GBAS,
block_ISP5_2_GBAS,block_group_adult,csr_PIC,csr_LPIC,csr_SA,csr_exception,cutover_status,cutover_datetime,
OutsideAgent,prfVchAttributes,uidResellerID,Category,uidDealID
from profiles where UidCustomerID in (352199267)

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Report Running Very Slow Compared To Query Analyzer - High TimeDataRetrieval

Jun 26, 2007

Hi,



I have a report in SQL Reporting Services 2005 which calls a stored proc and the report takes a very long time to run and sometimes returns zero records. But when i run the stored proc in query analyzer it takes about 4 seconds!!



I have checked the execution log on the RS using the below sql:






Code Snippet

use ReportServer

Select * from ExecutionLog with (nolock) order by TimeStart DESC



It shows that i have a large amount of time for the dataretrieval (601309ms, about 10mins) and does not return any records most likely because of a query timeout:



TimeDataRetrieval TimeProcessing TimeRendering Source Status ByteCount RowCount
601309 2227 3 1 rsSuccess 4916 0



The weird thing is that when i run it in query analyzer, i get about 400 records in 4 seconds !!



I dont understand what RS is doing to take up so much time like this to retrieve data.



The report is very simple - it basically returns the records straight out into a table.



The only thing I somewhat suspected was a parameter data type conflict between RS and SQL, specifically dates. I have a start and end date parameter in the report - i tried specifying this as date and string to see if it made any difference but it didn't.



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(4162 row(s) affected)

Table 'WebProxyLog'. Scan count 3, logical reads 873660, physical reads 3493, read-ahead reads 505939, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.

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The table and index scripts are below:




Code Snippet
-- =================== Table and Clustered index ===========================
CREATE TABLE [dbo].[WebProxyLog](
[ClientIP] [bigint] NULL,
[ClientUserName] [nvarchar](514) NULL,
[ClientAgent] [varchar](128) NULL,
[ClientAuthenticate] [smallint] NULL,
[logTime] [datetime] NULL,
[servername] [nvarchar](32) NULL,
[DestHost] [varchar](255) NULL,
[DestHostIP] [bigint] NULL,
[DestHostPort] [int] NULL,
[bytesrecvd] [bigint] NULL,
[bytessent] [bigint] NULL,
[protocol] [varchar](12) NULL,
[transport] [varchar](8) NULL,
[operation] [varchar](24) NULL,
[uri] [varchar](2048) NULL,
[mimetype] [varchar](32) NULL,
[objectsource] [smallint] NULL,
[rule] [nvarchar](128) NULL,
[SrcNetwork] [nvarchar](128) NULL,
[DstNetwork] [nvarchar](128) NULL,
[Action] [smallint] NULL,
[WebProxyLogid] [int] IDENTITY(1,1) NOT NULL,
CONSTRAINT [pk_webproxylog_webproxylogid] PRIMARY KEY CLUSTERED
(
[WebProxyLogid] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]

-- =================== Nonclustered Index ===========================

CREATE NONCLUSTERED INDEX [dta_ix_WebProxyLog_Kaction_clientusername_logtime_uri_mimetype_webproxylogid] ON [dbo].[WebProxyLog]
(
[Action] ASC
)
INCLUDE ( [ClientUserName],
[logTime],
[uri],
[mimetype],
[WebProxyLogid]) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]

-- =================== Query which is called regularly on the table ===========================

SELECT [User] = CASE
WHEN LEFT(clientusername,3) = domain' THEN RIGHT(clientusername,LEN(clientusername) - 3)
ELSE clientusername
END,
logtime AS [Date],
desthost AS [Site],
uri AS [Actual Site]
FROM webproxylog
WHERE CONVERT(Datetime,CONVERT(VarChar(25),logtime,106),106) BETWEEN '20 apr 2008' AND '14 may 2008'
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AND LEFT(mimetype,6) = 'text/h'
AND (uri NOT LIKE '%sometext.local%')
AND (uri NOT LIKE '%sometext.co.uk%')
AND [action] = 9
AND (clientusername IN ('USERNAME'))
ORDER BY logtime ASC;





PS There are 60,078,605 rows in the table

Please help!

Many Thanks

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OS Name Microsoft(R) Windows(R) Server 2003, Standard Edition
Version 5.2.3790 Service Pack 1 Build 3790
Other OS Description Not Available
OS Manufacturer Microsoft Corporation
System Name ARK-SQL
System Manufacturer HP
System Model ProLiant DL380 G5
System Type X86-based PC
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Processor x86 Family 6 Model 15 Stepping 6 GenuineIntel ~1866 Mhz
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SMBIOS Version 2.3
Windows Directory C:WINDOWS
System Directory C:WINDOWSsystem32
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Locale United States
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User Name Not Available
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Total Physical Memory 3,327.30 MB
Available Physical Memory 938.20 MB
Total Virtual Memory 1.10 GB
Available Virtual Memory 2.78 GB
Page File Space 2.00 GB
Page File C:pagefile.sys)

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Hello sql and .net gurus :-)I have a problem with my website www.eventguide.it. It's completly developed under .NET 2 and SQL Server 2005 Express. My problem is the folowing:The server is a Intel 3Ghz HT processor with 1GB Ram. No other page on the running system is a CPU consuming site. We optimized the SQL statements, the code, the caching and many other parts of the website (pooling on SQL access), but the SQL Server uses about 50% to100% of the CPU and about 400MB RAM all the time. The whole site seems to be very, very slow. In fact there are many of SQL operations on every page request, but we cache a lot of them in different ways (page output caching, application caching). So I don't understand we have so much performance problems. Any suggestions for optimised code in general? I read nearly all of the MS .NET performance papers - but real world experience is the missing part :-) It is better to cast the values of a SQL reader like thisDim String1 as String = Ctype(DataReader.item(0), String)Dim Integer1 as Intger = Ctype(DataReader.item(1), Integer)or like thisDim String1 as String = DataReader.item(0)
Dim Integer1 as Intger = DataReader.item(1)Thanks a lot for your help!FOX

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Hi list,
I'm a long time lurker on this list and really enjoy the discussions, although I rarely get a chance to participate.

Here is my situation: We are importing chunks of data (500 records at a time) from a C++ interface. The records have to be transformed before inserting into the target table which I am doing using a stored proc which is working fine. The records are in memory in C++ and the programmer is looping through the records building inserts into a temp table through ADO (which my proc picks up). The server business object is using the connection.execute method which is inserting one record at a time. That part of the process is taking over 15 seconds for 500 records which is the bulk of the total time.

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Hi guys.

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