Difficult Shrink Tempdb Question
Jul 2, 1999
How do you shrink the tempdb in SQL Server 7 after you allocated a large space to it but later realized you allocated too much.... I need to reclaim the space allocated to it but when I try to change the size or do a shrinkdb it either tells me I cannot shrink it smaller than allocated size or it shrinks tempdb to current (which is too large)... I looked online but could not find anything...
Any suggestions or assistance would be much appreciated... up to my eyes in tempdb..... Bill.
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Jan 18, 2008
I was able to find a few posts on this topic, but none of them quiteseemed to fit the situation, so I'm hoping that someone else might beable to help me here.I have a client who is using SQL 2005 (sorry, don't have the exactbuild with me). They run a weekly process which causes TempDB to growto over 100GB before it fails due to a full disk. Once it's grown tothat size we can't seem to shrink it again short of restarting theserver.The database is set to Simple recovery mode and I believe that it isset to auto shrink.Here are some things that found out/tried:DBCC SHRINKFILE (tempdev, 50000) does nothing.DBCC OPENTRAN returns no transactions.If I look in TempDB for any temporary tables, I get a couple dozen.They all have zero rows in them though. I didn't think to look at thecolumns that they contain, but maybe that will give me an indicationof their use. I used SELECT OBJECT_NAME(id), rowcnt FROMtempdb..sysindexes WHERE OBJECT_NAME(id) LIKE '#%'sp_spaceused shows that almost none of the space is actually beingused.I've looked for reindexing operations in their code and didn't seeany, but there's quite a bit of code there. While there are someoperations against some very large tables, I didn't see any obviouscartesian products or sorts either. Again though, there's a lot ofcode and I haven't profiled much of it.My plan right now is to reboot, set up a trace to track both filegrowths and SQL statements and then see if I can find whichstatement(s) are causing the TempDB to grow to be so large. Anysuggestions on additional things to track? Even given this though, Idon't know if that will help me with the shrinking issue, except topossibly prevent it from being necessary in the future.Any advice or suggestions welcome. Please let me know if I've left outany important information. I always seem to forget at least oneobviously important bit of information. :-)Thanks!-Tom.
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Dec 22, 1999
Hi,
We're running our database on SQL Server 7 and we've setup the tempdb to grow automatically.Gradually,it has grown upto 11390 MB and the used space is only 14 MB.It's not shrinking when we used the shrinkdb option.We cannot move the tempdb to RAM as it's very big.Can anyone help us in this...
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Jul 1, 1999
How do you shrink the tempdb in SQL Server 7 after you allocated a large space to it but later realized you allocated too much.... I need to reclaim the space allocated to it but when I try to change the size or do a shrinkdb it either tells me I cannot shrink it smaller than allocated size or it shrinks tempdb to current (which is too large)... I looked online but could not find anything...
Any suggestions or assistance would be much appreciated... up to my eyes in tempdb..... Bill.
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Jun 4, 2004
Hi Guys,
Tempdb in one of our SQLSERVER is standing at 5GB. I try to shrink it to 2GB, using following commands.
DBCC shrinfile(2,2000)
DBCC SHRINKDATABASE (tempdb, 2000)
It doesn't want to shrink at all... I ran sp_spaceused it give following results
Reserved data indx_size unused.
808 KB 384 KB368 KB 56 KB
I dont understand why tempdb doesnt want to shrink...?? help is greatly appericated.. thanks..
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May 30, 2002
Does tempdb ever need to be shrunk, or have it's log (does it even have one) dumped or does sql server handle this chore?
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Oct 1, 2007
One of my boxes was built with all of the system databases on the C: drive, and tempdb is up to 2 GB and there is no room left on the drive
It should have been installed on the D: drive
I've never had to do this before, mostly because I never install sql serevr on the c partition
Any war stories or suggestions
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Feb 8, 2006
Hello friends..
We are getting below error every day.we have job Shrink TempDB which runs every hour..but once a day we are getting this error.Is this error becasue of other jobs also running by that time which uses huge resource from DB..I cant understand why???.. can any body have an idea??
Executed as user: NT AUTHORITYSYSTEM. ...97031). The PageId in the page header = (1:1056620160). [SQLSTATE 42000] (Error 8909) Table error: Object ID -720718983, index ID 0, page ID (1:297030). The PageId in the page header = (1:-1839155936). [SQLSTATE 42000] (Error 8909) Table error: Object ID -720718983, index ID 0, page ID (1:297029). The PageId in the page header = (1:1057229472). [SQLSTATE 42000] (Error 8909) Table error: Object ID 0, index ID 0, page ID (1:297023). The PageId in the page header = (0:0). [SQLSTATE 42000] (Error 8909) Table error: Object ID 0, index ID 0, page ID (1:297022). The PageId in the page header = (0:0). [SQLSTATE 42000] (Error 8909) Table error: Object ID -720718983, index ID 0, page ID (1:297021). The PageId in the page header = (1:1056467424). [SQLSTATE 42000] (Error 8909) Table error: Object ID -720718983, index ID 0, page ID (1:297015). The PageId in the page header = (2:1071640160). [SQLSTATE 42000] (Error 8909) Table error: Object ID -7207189... The step failed.
Papillon
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Jan 29, 2008
I have a install of SQL 2005 that is about 5 months old. The tempdb.mdf and master.mdf files have ballooned to a huge size almost filling my hard drive. How do I reset them to a reasonable size?
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Jul 23, 2005
I have a problem with my TEMPDB Database.It gets extra size throughimporting data into one of my databases in same server.How can I shrink my TempDB Databse?Thanks
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May 10, 2006
Hi,
I'm running Sql 2000 with many users logged in. My tempdb database has grown to a large size 3/4 of it free space. Is there a way to shrink the database while users are logged on. I tried using the enterprise mgr. to shrink the tempdb database, but it did not work. How can I shrink this? It's using a ton of free space.
Thank You in advance
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Feb 11, 2002
I have a tempdb that was created at 1Gig. I don't know why but I want to shrink it below the original creation size. Is there a way to shrink this file or create a new file and delete the old?
I have tried shinkfile and shrink database with no luck.
Thanks Jeff
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Apr 17, 2002
A customer on SQL7 has a 40GB tempdb (which is usually 2-5GB) which has filled the drive. ShrinkDb/ShrinkFile do nothing as the db has only 2GB of free space. How can I truncate the data or blitz tempdb and create a new (2-5GB) one (Stopping the server, deleteing the .mdf, starting the server creates a new tempdb with the same size as the old one!)
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Oct 2, 2015
I need a script to Backup & Shrink tempdb.
namesize
tempdev1024
templog64
tempdev21024
tempdev31024
tempdev41024
tempdev51024
tempdev61024
tempdev71024
tempdev81024
I can't believe how many tempdb's there are?
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Apr 27, 2015
Output of below query is
SELECT session_id,
SUM(internal_objects_alloc_page_count) AS task_internal_objects_alloc_page_count,
SUM(internal_objects_dealloc_page_count) AS task_internal_objects_dealloc_page_count
FROM sys.dm_db_task_space_usage where internal_objects_alloc_page_count >10 and session_id> 50
GROUP BY session_id;
[Code] ....
Database MDF is 27806 MB and I tried to shrink but unable to shrink. It is production server.I do not want Restart sql server.There is no open transaction.
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Jan 5, 2007
If you have problems shrinking a transaction log no matter what commands you issue, here's a way to shrink the tranlog:
1. Right click on the properties of the database and go to the options tab.
2. Change the recovery mode to simple.
3. Right click again on the database - go to all tasks - shrink database.
4. Shrink the database.
5. Change the recovery mode back to what you had it as.
I found this out by trial and error as I could not find any documentation on it and no matter what I tried, I could not get the transaction log to shrink.
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Jul 14, 2004
Has anyone seen the SQL Server error:
"tempdb is skipped. You cannot run a query that requires tempdb"?
We're running a .Net web application with a SQL Server 2000 backend, and we get the error intermittently. Restarting the SQL Server service seems to fix it, as it causes tempdb to be rebuilt, but this isn't a long term solution. Any direction or hints would be greatly appreciated. Thanks!
- Mike
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Dec 15, 2006
I have the following table:tblFriendsOwnerCode FriendCode7 107 1410 710 1210 1312 1013 1013 1814 718 13
I need a SP which return the following (im unsure about the best return datatype and the sql statement):
I want return all friendcodes of user nr 7 (10 and 14)and I want to return all friendcodes of user 10 and 14 (7,12,13,7) WITHOUT user 7
(if possible WITHOUT the use of a temptable!)
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Mar 11, 2008
I have roles set up for different companies. The role names are structured companyname_department, ex.,
CallawayContracting_SalesDepartment
CallawayContracting_Administration
FredsAutobody_PaintSales
How would I search the roles and return only departments that belong to a certian company and also users that belong to a certian company. I appear to have gotten myself into quite a bind. Any help would be much appreciated! I will be certian to click best answer.
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Apr 6, 2008
I'm pretty new to this so I'll explain as best I can.
I am building a small DB which will track attendance for employees based on a point system. I believe I'm almost there (with this piece) but am stuck.
The basic concept:
1. Collect all records from the attendance table for the previous 14 day period
2. sum the points column in the attendance table and group by UID, storing in a new table called TOTAL_POINTS ONLY for those UID's which have a value > 0
3. Perform a basic insert into statement on the attendance table for each UID matching those found in the previous TOTAL_POINTS table
Number 3 is where I'm failing and could really use some help.
My code thus far...
-------------------------------
/*Declare local variables for current date and start date.*/
--
DECLARE @DateNow DATETIME
DECLARE @StartDate DATETIME
SET @DateNow=getdate()
SET @StartDate = DATEADD(Day, -14, @DateNow)
--
/*Create table to hold totals for future calculations*/
CREATE TABLE POINT_TOTALS
(UID int, TOTAL float)
/*select ALL records from the table within the above defined date range
and group them by UID tallying the score column*/
--
INSERT INTO POINT_TOTALS
SELECT UID, SUM (POINTS) AS TOTAL_POINTS
FROM attendance
WHERE date >= @StartDate
GROUP BY UID
--
/*If the TOTAL_POINTS > 0 for the 14 day period, insert a record in to the
attendance table which deducts .5 points for the UID in question*/
*** This is where I'm failing ***
--This was just to make sure I was returning the correct results to the POINTS_TOTAL table.
SELECT UID FROM POINT_TOTALS
WHERE TOTAL > 0
/*All I want to do now is for each of the UID's in the POINT_TOTALS table,
I want to perform a basic insert on the ATTENDANCE table where the UID's in both
match. I would think this to be fairly simple but I can't seem to figure it out.
*/
DROP TABLE POINT_TOTALS
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Apr 25, 2008
--This is works
SELECT *
from vwClientsByAge
WHERE age like '18'
--This gives me an error
SELECT clientId, firstName, age
from vwClientsByAge
WHERE age < CONVERT(int, '18')
Error: The conversion of a char data type to a datetime data type resulted in an out-of-range datetime value.
Whats wrong with the conversion?
However, this works:
SELECT age
from vwClientsByAge
WHERE age < CONVERT(int, '18')
What is wrong?
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May 29, 2008
Hey i have a query i need help with.
I have a table where i have 4 columns in it which i need to group together and then sum up a cost column also. I want to sum up the columns where i have a parent and and child and then i want to sum up the other column where i have only a child.
Example of the data is below. I think i need to do this in a sub query
ID Ind Parent Child Cost
P110041012705921.8000
W11004101270595.4500
A110041012705921.8000
B110041012705916.3500
R110041012705916.3500
B0100420043.3000
P0100420043.3000
W0100420021.6500
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Aug 2, 2005
Hello !This is my table:Ordernr Date ArticleO1 1.1.05 22O2 2.2.05 33O3 5.5.05 22O4 2.2.05 33O7 8.8.05 55I need one result-row for each article with the newest Order(max(date)):article lastDate lastOrdernumber22 5.5.05 O333 2.2.05 O455 8.8.05 O7How can I get this ?I tried this:SELECT distinct article, max(date), max(ordernr)FROM tableGROUP BY articlearticle and max(date) is ok, but I am not sure that max(ordernr) andmax(date) comes from the same row.I think, I will need complex subqueries.Many thanksaaapaul
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Jan 25, 2006
Hello !I habe 2 TablesTable1: OrdersFields: Ordernr, OpiecesTable2: CalloffsOrdernr, CpiecesIn Table1 ordernr is primary key.In Table2 the same ordernr can exist oftenMy problemIf the sum(Cpieces) < Opieces:I have to create a new virtual calloffwith Cpieces = opieces - sum(cpieces)Its too high for me.Please helpBest regardsaaapaul
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Jul 20, 2005
HiI am trying to produce an update trigger. I understand the concept ofdelete and insert triggers without a problem. Unfortuantely, theupdate triggers do not have particularly simple documentation in BoL.So, can someone please explain to me, quite simply how I would producea trigger on the following:I have table 1 which we'll call simon. In here are various columns androws. I also have table 2, called simon_a, my audit table.Whenever anything is updated or deleted in simon, I want it sent tothe simon_a table. Delete, as above, is fine since it's conceptual buthelp me out on the update one. I cannot seem to figure out how to getthe information from the table before it's updated.As ever, champagne and beer for the successful answer.With thanksSimon
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Jul 20, 2005
I have a table that stores billing rates for our employees by client.Each employee can have a different billing rate for each client for aspecified period. Here are the columns in the table.eid - Employee ID#cid - Client ID#startdt - start date of billing rateenddt - end date of billing ratebrate - billing rateI need to create a script that will verify that for a given eid, and cidthat either the startdt or enddt for one billing rate, the periods donot overlap.For example, I need to be able to detect overlaps such as this:eid cid startdt enddt brate001 001 1/1/2003 12/31/2003 $50001 001 11/01/2003 04/01/2004 $75*** Sent via Developersdex http://www.developersdex.com ***Don't just participate in USENET...get rewarded for it!
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Jul 20, 2005
suppose I have the following table:CREATE TABLE (int level, color varchar, length int, width int, heightint)It has the following rows1, "RED", 8, 10, 122, NULL, NULL, NULL, 203, NULL, 9, 82, 254, "BLUE", NULL, 67, NULL5, "GRAY", NULL NULL, NULLI want to write a query that will return me a view collapsed from"bottom-to-top" in order of level (level 1 is top, level 5 is bottom)So I want a query that will returnGRAY, 9, 67, 25The principle is that looking from the bottom level up in each columnwe first see GRAY for color, 9 for length, 67 for width, 25 forheight. In other words, any non-NULL row in a lower level overridesthe value set at a higher level.Is this possible in SQL without using stored procedures?Thanks!- Robert
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Jan 6, 2008
I Installed CE 3.1 months ago to play around with it to see how easy or difficult it would be to move from SQL Express to CE. Got it all to work with SQL Managment and VS 2005. Now, months later I am back to really upgrading my product to use CE. Oops, now we are on version 3.5. Decided to stay with 3.1 until I realized transact-sql command "TOP" is not supported in 3.1. So, onto the hours of research to do a simple upgrade. Here's where I stand:
1. Uninstalled CE 3.1. Installed CE 3.5. Oh, if only it were that easy. Visual Studio 2005 is still using the dll from 3.1 and still can only see reference to 3.1 in the GAC.
2. SQL Management Studio now cannot open the .sdf database.
3. There is no mention of using CE 3.5 with VS 2005, only VS 2008. Is VS 2008 a requirement to be able to work with .sdf file in VS? I remember I had to install "Microsoft SQL Server 2005 Compact Edition Tools for Visual Studio 2005" when I went through the first installation of CE. Is this now obsolete if I want to use 3.5? I don't even remember what its purpose was other than I needed it.
It seems there is and upgrade.exe file that need to be run command line to updgrade my .sdf file. Are you kidding?
Has anyone upgraded while still using VS 2005? Any advice is greatly appreciated.
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Nov 22, 2006
Why have you made connecting to a sql server express database so difficult?
I have it working locally, but going to production has been nothing but a nightmare.
I can't even connect locally on the production box.
I am on a dedicated server and my login is an Admin on the box. I have just installed SQL Express + the fancy management interface.
I have made a copy of my database that I was connecting to dynamically (which was failing remotely) and I have attached it to the server. I have made myself a user of the database and granted my self evey permission available.
I have turned on impersonation in my web.config. The database knows it's me trying to connect and STILL denies me when I'm actually ON the production server. It is not even a remote connection problem.
How can I sit there an look at myself as a user of the database in the admin interface, yet I cannot connect via a web app. With SQL server 2000 and MSDE it was soooo simple....
Here is a snippet from my web.config
<connectionStrings>
<remove name="LocalSqlServer"/>
<add name="LocalSqlServer" connectionString="Data Source=localhost;Integrated Security=True;Initial Catalog=TEST" providerName="System.Data.SqlClient"/>
...
</connectionStrings>
Here is the error:
Cannot open database requested in login 'TEST'. Login fails.
Login failed for user 'DEDICATEDquick'.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.Data.SqlClient.SqlException: Cannot open database requested in login 'TEST'. Login fails.
Login failed for user 'DEDICATEDquick'.
I have a screen shot of the admin interface to prove I am a user.
This should be a 5 minute task that has eaten up days.
So frustrated...
Bernie Quick
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Nov 13, 2006
Hi.
I am developing for a system that receives an input from an external modem.
The Transaction is split into 2 sections,
Section 1 = grants the transaction ID,
Section 2 = deliver the transaction Data.
I have 2 corresponding tables,
One called tblremoteunitrequestID (Where the transaction ID is granted)
The other called tblremoteunitrequests (Where the transaction is completed, about 1 second later)
I am writing a diagnostic report that determines if the first part of the transaction completes but the second part fails.
I am having difficulties designing the SQL for this.
Here is some sample data for tblremoteunitrequestID: (The first stage of the transaction)
RecordDate | Serial
13/11/2006 14:00:36 0000-0000-0000-0006
13/11/2006 14:00:30 0000-0000-0000-0004
13/11/2006 13:59:04 0000-0000-0000-0092 (This didtn transaction didnt complete)
13/11/2006 12:15:22 0000-0000-0000-0092 (nor did this one)
13/11/2006 10:31:54 0000-0000-0000-0092
13/11/2006 10:00:29 0000-0000-0000-0006
Here is some sample data for tblremoteunitrequests: (The second stage of transaction, 1st stage has to be completed beforehand)
DateReceived | Serial
13/11/2006 14:00:37 0000-0000-0000-0006
13/11/2006 14:00:31 0000-0000-0000-0004
13/11/2006 10:31:56 0000-0000-0000-0092
13/11/2006 10:00:31 0000-0000-0000-0006
13/11/2006 10:00:25 0000-0000-0000-0004
13/11/2006 07:19:13 0000-0000-0000-0020
From this data I can see that serial number 0000-0000-0000-0006 Successfully completed part 1 and part 2 of the transaction, as did serial number 0000-0000-0000-0004.
Serial number 0000-0000-0000-0092 had trouble, it connected at 13:59:04 (tblremoteunitrequestID) but part 2 didnt complete, so it wasent saved in tblremoteunitrequests. The same happened at 12:15:22 but at 10:31:54 it was successful so it was saved.
I Only want to display the transactions that didnt complete, sounds easy huh?
This is what I hope to get in my Results table:
DateReceived | Serial
13/11/2006 13:59:04 0000-0000-0000-0092
13/11/2006 12:15:22 0000-0000-0000-0092
I was experimenting with T-SQL today, this is what I have done so far:
SELECT DISTINCT
TBLRemoteFeildUnitRequestID.Serial, TBLRemoteFeildUnitRequestID.RecordDate,
CASE WHEN TBLRemoteUnitRequests.DateReceived BETWEEN DATEADD(SECOND,-1,TBLRemoteFeildUnitRequestID.RecordDate) AND DATEADD(SECOND,10,TBLRemoteFeildUnitRequestID.RecordDate)
THEN ' Ok'
ELSE ' Not ok'
END AS PROBLEM
FROM TBLRemoteFeildUnitRequestID LEFT OUTER JOIN
TBLRemoteUnitRequests ON TBLRemoteFeildUnitRequestID.Serial = TBLRemoteUnitRequests.Serial
WHERE TBLRemoteFeildUnitRequestID.RecordDate BETWEEN DATEADD(WEEK, - 2, GetDate()) AND GetDate()
ORDER BY RecordDate DESC
This kinda worked, but it caused records that satisfied the between condition to be displayed twice, once as "Ok" and once as "Not ok".
Heres a sample of the result I got:
Serial | RecordDate (1st part of transaction) | Status
0000-0000-0000-0006 2006-11-13 14:00:36.000 Ok (Duplicated)
0000-0000-0000-0006 2006-11-13 14:00:36.000 Not ok
0000-0000-0000-0004 2006-11-13 14:00:30.000 Not ok (Duplicated)
0000-0000-0000-0004 2006-11-13 14:00:30.000 Ok
0000-0000-0000-0092 2006-11-13 13:59:04.000 Not ok (Correct) (Not duplicated)
0000-0000-0000-0092 2006-11-13 12:15:22.000 Not ok (Correct) (Not Duplicated)
0000-0000-0000-0092 2006-11-13 10:31:54.000 Not ok (Duplicated)
0000-0000-0000-0092 2006-11-13 10:31:54.000 Ok
0000-0000-0000-0006 2006-11-13 10:00:29.000 Ok (Duplicated)
0000-0000-0000-0006 2006-11-13 10:00:29.000 Not ok
I have just about had enough, I have wasted an entire day on this
Someone please Help
Dan
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Jan 4, 2000
Hello:
I am working with an application in mssql 65.5, with sp4.
I have the database option 'truncatelog on checkpoint' set, there are no transaction log dumps taken at this time.
We plan now that y2k is over to upgrade to sp 5a. I am not not sure the new configuration
parameter 'logLRU buffers'(I don't have the sp5a readme text with me now) in our situation.
Here is our situtation with the transaction logs: The log, mostly with month-end high actvity,
fills up when long-running, high activity transactions are run.
The log gets to 100% sometimes rather quickly and sometimes near that or above 80%easily.
We check with dbcc open tran and there are no current transaction running. We expand the log just a little.
But it still shows 100@ used when we run dbcc sqlperf (logspace).
Here's the rub: when we try to dump the log, with wither or both back-to-back: dump tran abcdb
with truncate_only and then dump tran with no_log still nothing happens.
Sometimes we stop and start the mssql server and that helps but not always and sometimes when
we are really desperate we stop/start the NT server box(at off hours). Sometimes, the transaction log
reduces to nearly 0% used when we run dbcc sqlperf (logspace) and sometimes not. So we run dump tran
a couple of more times. We wait for several minutes usually to if the dump tan started and if it shows up
under EM under curent activity
This is becoming very frustrating and dangerous as well.
1) has any one had similar experiences with mssql 6.5 sp4?
2) Can anyone advise what we can do to more easily to dump the transaction log? Are we doing
any thing really wrong?
3) Would upgrading to sp 5a really help or should we just start planning upgrading to mssql 7.0?
Any suggestiosn you can furnish will be helpful. Thanks.
David Spaisman
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Jul 6, 2005
hello,
I could need some help with a little query.
table "acme"
name1 varchar(128)
name2 varchar(128)
idate datetime
content
A,H,1/1/2005
A,H,2/1/2005
A,I,2/1/2005
A,J,3/1/2005
B,K,4/1/2005
B,L,5/1/2005
I want the following result (for 'A'):
1/1/2005,1
2/1/2005,3
3/1/2005,4
I want to filter for Column "Name1" and cumulative count the entries grouped by date.
what's the simplest solution?
best regards, thilo.
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Sep 20, 2007
I'm writing a workflow management application for my work, and its somewhat complicated, here's a general idea of how it works:
- Anything that a company does is defined by a workflow.
- A workflow consists of tasks.
- Some tasks in a workflow can't be started until other tasks have been completed. If task A can't be started until tasks B and C are finished, then task A depends on B and C.
You might imagine that a bank has a workflow for handling a house loan. Before a bank could sign a contract with an applicant, they'd need proof of house ownership, but before they could get proof of house ownership they need an applicant's proof of identity like a driver's license or military ID.
Here's an oversimplified visual:
Each arrow points to its dependency. Each task can have multiple dependencies.
The setup above is represented in the database by a Tasks and a Dependencies table. Tasks has an ID field, and Dependencies has a TaskID and DependencyID field which are both foreign keys to Tasks.ID.
Code:
[Tasks]
ID Status Name
-- ------ ----
1 Done Start Processing Loan Application
2 Done Photocopy applicant's driver's license
3 NotDone Photocopy proof of house ownership
4 NotDone Get a copy of applicant's W-2 forms
5 NotDone Perform credit check on applicant
6 NotDone Sign loan contract
[Dependencies]
TaskID DependencyID
------ ------------
1 0
2 1
3 1
4 2
5 2
5 3
6 4
6 5
Tasks has a many-to-many relationship with itself.
Here's the hard part:
- A task can't be started until all of its dependencies have been completed.
- after a task is completed (meanings its status is marked "done"), I need to return a list of all the new tasks that are ready to be started.
When TaskID 2 is marked "Done", then TaskID 4 is ready to begin; however, TaskID 5 is not ready to begin since it depends on 2 and 3, and 3 hasn't been completed yet.
The requirements of the query are very simple, but the implementation is difficult.
I'll post a prelimenary solution in the next post:
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