My select process with isolation level=CS on a table with locksize =
row waits until the other insert process commits.I don't lock the
table level and if I change the select process' isolation level to UR,
it doesn't wait.
I would like to have my processes with CS isolation level to be able to
read all "clean" rows without any wait. How can I make them skip dirty
rows?
Regards,
Mehmet Baserdem 5 1719
You can do this using DB2 REGISTRY VARIABLES like
DB2_EVALUNCOMMI TTED
Check the DB2 ADMIN GUIDE
or using Proper indexes
cheers....
Shashi Mannepalli
Mehmet Baserdem wrote: My select process with isolation level=CS on a table with locksize = row waits until the other insert process commits.I don't lock the table level and if I change the select process' isolation level to UR, it doesn't wait.
I would like to have my processes with CS isolation level to be able to read all "clean" rows without any wait. How can I make them skip dirty rows?
Regards,
Mehmet Baserdem
Mehmet Baserdem wrote: My select process with isolation level=CS on a table with locksize = row waits until the other insert process commits.I don't lock the table level and if I change the select process' isolation level to UR, it doesn't wait.
I would like to have my processes with CS isolation level to be able to read all "clean" rows without any wait. How can I make them skip dirty rows?
Regards,
Mehmet Baserdem
DB2_EVALUNCOMMI TTED http://publib.boulder.ibm.com/infoce...e/c0011223.htm
Cheers
Serge
--
Serge Rielau
DB2 Solutions Development
IBM Toronto Lab
Probably you need DB2_SKIPINSERTE D.
Let's say, that there are 10 rows in table1.
UserA inserts 1 row without committing data.
UserB issues "select * from table1 with cs" and receives 10 rows. He is
not aware of the newly inserted row, until it's committed. http://publib.boulder.ibm.com/infoce...n/c0012389.htm
-- Artur Wronski
Thanks Artur, DB2_SKIPINSERTE D register resolved my problem.
DB2_EVALUNCOMMI TTED didn't work for me with the following
configuration:
DB2 Client ver 8.1.4 and DB2 server ver 8.2.2
I guess we better to use DB2_SKIPINSERTE D register for the db2 servers
of version v8.2.2.
regards
Mehmet Baserdem
Mehmet,
DB2_EVALUNCOMMI TTED just checks if the evaluated row fits the query
criteria.
Let's say there are 10 rows in table table1:
1, 'A'
2, 'B'
3, 'C'
4, 'D'
....
UserA updates row #3 without committing data:
update table1 set col2='X' where col1 = 3
UserB issues:
select * from table1 where col2='A' with cs
and receives one row 1,'A'
Without the registry variable UserB have to wait (as there are no
indexes in table1 and DB2 is forced to do sequential scan).
But this variable can cause some inconsistencies .
If UserB issues:
select * from table1 where col2='C' with cs
will receive no rows, as current evaluated value is 'X'. But if userA
rollback the work the same query will return one row.
So, bottom line is: the variable can increase concurrency when users
are working on excluding data sets (in the same table).
-- Artur Wronski This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics |
by: francis70 |
last post by:
Hi,
I have these 2 problem? Is there a way in Oracle to read UNCOMMITED
data. i.e. in Oracle the normal behaviour is that a user's updates to a
table are visible to other users ONLY when the user commits. But in
Informix there is this thing called ISOLATION LEVELS. For example by
setting the ISOLATION LEVEL to DIRTY READ, a user will read dirty data,
i.e. the last uncommited updated value of a field by some other user. Is
|
by: Bob |
last post by:
Does anybody know what might cause the following message to show up in
the SQL Server Error Log?:
Time out occurred while waiting for buffer latch type 2, bp
0x12260f80, page (5:77914), stat 0x40d, object ID 7:421576540:0,
waittime 500. Continuing to wait.
I've read several articles about what to do about this situation on
SQL Server 2000, but I'm running SQL Server 7.0. Specifically, I'm
running version 7.00.842. Is there a way to...
|
by: Holyman |
last post by:
Hi group
I have an application running on a couple of pc's all connecting to
the same SQL-serve databaser. The other day one of my applications
started a transaction which it never committed (programming error) .
The application continiued running for a couple og hours filling every
insert and update statement to the sql-server log-file, where they
remain rigt now. The applications on all the other machines
deadlocket because they...
|
by: Daniel Chou |
last post by:
Hello,
We are running java applications which uses DB2 as the data store.
But sometimes we get the following exception:
2004-04-25 22:51:39,478 FATAL
LogService.logFatal(LogSer
vice (?:?) - JavaException: Error 11070 Collaboration exception at
step 3 in VBJ
ThreadPool Workerjava.lang.Object@692a4004CxCommon.FlowExecContext@6954c004.mai
|
by: wxqun |
last post by:
I'm try tuning a SELECT statement which is used by a Cognos cube on a
DB2 V7.2 +FP13. After I did the tuning, the "dynexpln" shows the
"total cost" is down to 8214567 from 37345265, also I try to run the
SQL in the cmd line, it now only took several minutes to return about
50M rows instead of +10 hours.
The cube is re-built after the tuning, and I could see the same SQL
running by "get snapshot for application.." , also the "list...
| |
by: wxqun |
last post by:
I'm trying tuning a SELECT statement which is used by a Cognos cube on
a
DB2 V7.2 +FP13. After I did the tuning, the "dynexpln" shows the
"total cost" is down to 8214567 from 37345265, also I try to run the
SQL in the cmd line, it now only took several minutes to return about
50M rows instead of +10 hours.
The cube is re-built after the tuning, and I could see the same SQL
running by "get snapshot for application.." , also the "list...
|
by: Sam Durai |
last post by:
Hello, is there is any snapshot element availble which could give the
no of uncommited Insert/Update/Delete stmts there were executed by an
application.
In the app shap I understand that this element "Update/Insert/Delete
statements executed" would give the list of Up/In/Del that have been
executed after the connection has established.
Thanks,
Sam.
|
by: prakashgrp |
last post by:
Hi,
first i am new to sql server:
server version is sql server 2000
we used to get lot of blocking session and we thought of use isolation level read uncommited instead of read commited(default behaviour)
could any body advise me to set this parameter in database level
|
by: jankhana |
last post by:
Hi all,
I'm having an application in that i use Sql Compact 3.5 with VS2008. I'm running multiple threads in my application which contacts the compact database and accesses the row. It selects and deletes those rows in a fashion i.e selecting and giving to the application 5 rows and deleting those rows from the table. It works great with a single thread but if i use multiple threads i.e if 3 or more threads are running I get very...
|
by: Oralloy |
last post by:
Hello folks,
I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>".
The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed.
This is as boiled down as I can make it.
Here is my compilation command:
g++-12 -std=c++20 -Wnarrowing bit_field.cpp
Here is the code in...
|
by: Hystou |
last post by:
Overview:
Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For most users, this new feature is actually very convenient. If you want to control the update process,...
| |
by: tracyyun |
last post by:
Dear forum friends,
With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each protocol has its own unique characteristics and advantages, but as a user who is planning to build a smart home system, I am a bit confused by the choice of these technologies. I'm particularly interested in Zigbee because I've heard it does some...
|
by: conductexam |
last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one.
At the time of converting from word file to html my equations which are in the word document file was convert into image.
Globals.ThisAddIn.Application.ActiveDocument.Select();...
|
by: TSSRALBI |
last post by:
Hello
I'm a network technician in training and I need your help.
I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs.
The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols.
I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls...
|
by: adsilva |
last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
|
by: 6302768590 |
last post by:
Hai team
i want code for transfer the data from one system to another through IP address by using C# our system has to for every 5mins then we have to update the data what the data is updated we have to send another system
|
by: muto222 |
last post by:
How can i add a mobile payment intergratation into php mysql website.
| |
by: bsmnconsultancy |
last post by:
In today's digital era, a well-designed website is crucial for businesses looking to succeed. Whether you're a small business owner or a large corporation in Toronto, having a strong online presence can significantly impact your brand's success. BSMN Consultancy, a leader in Website Development in Toronto offers valuable insights into creating effective websites that not only look great but also perform exceptionally well. In this comprehensive...
| |