JunGuo 270006BN0K Visits (206)
Alfresco Connector is now available in Fix Central. The customer distribution file can be downloaded at Fix Central
Overview of Changes
Slakshmi 060001JD9S Visits (389)
Looking for a way to test Automatic Client Re-route using a simple JDBC program that uses IBM data server driver for JDBC & SQLJ (JCC) & JDBC DriverManager Connection?
Here are the steps to follow:
Step 1: UPDATE ALTERNATE SERVER INFORMATION in BOTH PRIMARY & STANDBY SERVERS:
Lets assume that following are the Primary and Standby Server's hostnames and Port numbers.
a) On DB2 Primary system:
Step 2: UPDATE THE JDBC CONNECTION URL WITH THE clie
Sample program to test the automatic Client re-route:
To compile the program:
Step 3: Once you run the above program, it connects to the primary. On the DB2 server, do a failover to the standby. Now the application will automatically re-route the connection to the former standby.
0XST_John_Gera 2700020XST Visits (846)
There are situations where in a HADR environment, transaction on the Primary are bloc
Brewer's CAP Theorem:
Brewer's CAP theorem states that, in a Distributed Computer System, we can guarantee only two of the following simultaneously:
- Consistency (all nodes see the same data at the same time)
- Availability (a guarantee that every request receives a response about whether it was successful or failed)
- Partition tolerance (the system continues to operate despite arbitrary message loss or failure of part of the system,)
Figure 1. Venn Diagram above shows that there can be only 2 of Consistency(C), Availability (A) or Partition tolerance(P) at a given time
Now putting that in terms of DB2 HADR for a LOGGED OPERATION:
Consistency (C) - Data is the SAME on Primary and Standby
Availability (A) - Clients are ALWAYS able to connect and get a response (i.e no blocking)
Partition Tolerance (P) - Netw
Basically the theorem says that in the presence of a partition event (like a network outage between the 2 hadr nodes) there MUST BE a tradeoff between availability and consistency.
HADR sync modes are the primary dial to control C vs. A tradeoffs:
Transaction are committed on the Primary after relevant logs have been written to disk on Primary and:
SYNC --> logs have been written to disk on Standby as well ==> Highest C (Data guaranteed on Standby)
NEARSYNC --> Logs are received into memory on Standby ==> More C
ASYNC --> Logs sent to the Standby on the Network (Don't wait for ACK) ==> More A
SUPERASYNC --> Don't wait for Standby!! ==> Highest A (No guarantee)
In SYNC mode, the total time for a log write = Σ (Primary_Log_Write + Log_Send + Standby_Log_Write + Ack_Message)
Figure 2: Shows the various sync modes
Further fine tuning C vs A :
HADR_TIMEOUT --> How long to wait before considering communication failure. Till we reach this time we are still considered PEER ==> More C
HADR_PEER_WINDOW --> In case of communication failure, how long to wait before actually breaking the connection ==> More C
When both HADR_PEER_WINDOW and HADR
Where does DB2_HADR_BUF_SIZE and DB2
DB2_HADR_BUF_SIZE --> For increasing the HADR standby log receive buffer size
Higher DB2_HADR_BUF_SIZE and DB2
In situation where we see the Transaction being blocked on the Primary, it is because the HADR setup is in favor of C vs A. For example:
1. Sync Mode = SYNC/NEARSYNC
2. There is a Partition event (standby log buffer full/network failure)
Then we see blocking on Primary i.e no A. In such situations we can tune:
- DB2_HADR_BUF_SIZE - (to get CA)
Note: Starting v10.1 we have introduced a new parameter 'HADR_SPOOL_LIMIT'. Log data that is sent by the primary is written, or spooled, to disk on the standby if it falls behind in log replay. The standby can later on read the log data from disk.
Bada Bing Bada Boom!! :)
Slakshmi 060001JD9S Visits (287)
Looking for step by step instructions for Installing DB2 on Windows?
Here are the education modules available with detailed description of each step in DB2 installation on Windows Operating System.
JunGuo 270006BN0K Visits (241)
kdillon 20000024FQ Visits (187)
JunGuo 270006BN0K Visits (185)
wilhap 0600007F3T Visits (207)
Please add the dates to your calender Apr 27 - May 1, 2014
The sessions chosen to present at the 2014 IIUG Conference cover a multitude of topics pertinent to Informix users and administrators; including many popular Informix features, as well as tried and true "must have" topics like those involving maximizing your system performance while minimizing system downtime. Our speakers for this year's conference are the best the Informix community has to offer, including not only the familiar faces, but also new speakers eager to share their experience and expertise. The sessions we've selected include both interesting and relevant topics that can be used to reinforce your professional skills and keep current in today's ever changing market. Remember, the 2014 IIUG Conference is NOT "Just For DBAs": Bring your application developers too!
Here's a sneak peak at this year's upcoming sessions:
Stay tuned, we will soon be uploading sessions to the conference website. Please continue to review the website for regular updates. It will be refreshed to include details of sessions, hands-on-labs, and tutorials as they become available. The 2014 IIUG Conference in Miami will be our best conference yet.
KateDawson 060001TQ2C Visits (281)
Exciting news today for everyone who likes to read technical content on the go... a brand new IBM Redbooks mobile app is now available! This app provides access to Redbooks publications, announcements, and social sites. You can download the app for both iOS and Android devices.
Check out the blog
kdillon 20000024FQ Visits (300)
Three new IBM InfoSphere Information Server training modules are now in production:
IMLillianLei 120000CR7P Visits (369)
Logging helps debugging JavaAPI programs. In this blog, I will show you how to log JavaAPI logs for MDMCS. This information applies to MDMPIMv9.1.x, MDMCSv10.1.x and MDMCSv11.0.x.
1. Check JavaAPI logging from log.xml
<category name="JavaAPI" additivity="false">
2. In Java program,
1) import Logger class.
2) create Logger object and invoke the logger object.
Context ctx = PIMC
3. Find the JavaAPI logging information.
You may run the usecase to invoke the JavaAPI program, then find the logging information from $TOP
For example, the above code logged one line in javaapi.log file as follows.
2014-01-15 14:32:28,083 [Wor
MaryKKassey 2700055CKK Visits (429)
Here is a collection of useful DB2 Performance Tips from our DB2 Advanced Problem Determination team, please visit this link for details which currently includes the following blogs:
Follow our blogs, post your question and keep watching for more!
0XST_John_Gera 2700020XST Visits (498)
The db2ReadLog API is used to read log records from the DB2® database logs, or queries the Log Manager for current log state information.
Bada Bing Bada Boom!!
kdillon 20000024FQ Visits (326)
Two new external self-assist videos went to production on 1/17/2014. These modules are now found on the IBM Education Assistant website in the IBM Electronic Support tools and resources -> Download fixes and updates section.
KateDawson 060001TQ2C Visits (462)
To more quickly and accurately address your issues, we are making an important change to our IBM Software Appliance Service Request process. These changes will take effect between now and July 2014.
What you need to know:
Here is a screen shot of how you will enter your serial number in the Service Request Tool:
For more information, please refer to the links in the What you need to know section above.