there are a couple of finer points that are left out... There are really two versions of TAF that they are talking about here...
1) Session Failover -- it's easy to do, just rebuild the TNSNAMES.ORA file on the client machine, and create a backup connection. If the connection fails to connect to the primary, it will retry it on the secondary, after XX number of seconds (and a couple other options as well.) The client has no idea that it even reconnected. This works with about 99% of applications written with OCI8. However, since all it does is reconnect the user, any in process transactions are lost, and the user does not know it until they try and commit, and then they select that data back, and only half of it is there. It's a risky solution, but works GREAT for demos. 2) Session Failover and reprocessing of in process transactions - This method actually replays any in process activities on the secondary node, and then allows the user to continue on as if nothing happened. This is one way not to have perceived data corruption. But it does require extensive modification to the OCI connection layer so that the Client product is 'TAF aware' And it means the client software must record all the uncommitted activity that a session does, so that when oracle fails it to the other machine, it knows to replay that activity before giving any response back to the user. This works today in SQL*Plus without any modification (try it it's pretty cool) but will require HUGE amounts of code changes to any other app to get it to work. (i.e. try it with Oracle forms, or People Soft clients -- no chance it will work.) so, the Microsoft is right and wrong at the same time... odd how they do that so well. Nick -----Original Message----- Sent: Wednesday, July 02, 2003 10:04 AM To: Multiple recipients of list ORACLE-L Has anyone read the articles? One point states that failover for RAC requires coding changes to take advantage of it. Not from the demo I saw. HPaq (or whoever they are these days) took a circa '99 Oracle test GUI called Oracle Workload Generator and got failover to work with only changes to the sqlnet.ora. I've seen the demo twice, once with Unix servers and once with Windohs servers (since the app is Windohs, the client had to be Windohs), and while the Unix did the failover much faster (1-2 secs vs. 20-30 secs), both worked seamlessly. As an aside, the load balancing queries worked flawlessly, too. So, what's the case for code changes? Makes me want to read the articles further... Rich Rich Jesse System/Database Administrator [EMAIL PROTECTED] Quad/Tech Inc, Sussex, WI USA -----Original Message----- Sent: Tuesday, July 01, 2003 1:00 PM To: Multiple recipients of list ORACLE-L FYI One of my friends at Microsoft, (yes I must to confess, I have friends at MS) gave me a "present", it's a 4 cd's kit called "SQL Server 2000 for the Oracle Customer", the kit consist in 4 cd's with demos, docs, presentations, videos and a lot of stuff showing why sql server is a better option as a DB instead oracle, contains price lists, performance evaluation and many other "information", maybe you'd like to spend some of your time giving Billy a chance to defend his product. The 4 cd's are available (almost completely) as links in: http://www.microsoft.com/sql/oraclekit Any comments? Gabriel -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Jesse, Rich INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Nick Wagner INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
