Re: HDR and Client Redirection

Obnoxio The Clown wrote: > Karl Ostner said: > >>Joachim, >> >>you can do it this way: >> >>sqlhosts file: >>myServer group - - >>myServer1 onsoctcp myHost1 myPort1 g=myServer >>myServer2 onsoctcp myHost2 myPort2 g=myServer >> >>setup HDR pair using myServer1 and myServer2. >> >>for your client, set INFORMIXSERVER=myServer > > > That is documented to work as far as ER is concerned, but TFM does not > explicitly say that it's OK for application use. I would love this to work > for everything, can someone confirm whether it's a documentation issue or > whether it's not supported for application use. > It works in all applications with or without ER running. We began to use this when DBPATH was broken in CSDK 2.60 or so (forget the release) and have never wanted to go back. It's much more elegant and the DBAs have control over the failover cascades. With DBPATH you're at the user's mercy: User: "The primary server crashed and I can still connect to the database with dbaccess through the backup server. Why isn't my application connecting?" DBA: "What's the app?" User: "We just run flugelhorn.exec!" DBA: "Hmm, flugelhorn.exec works for me!" User: "Well it doesn't work out of the cron script that starts it up hourly!" DBA: "<sigh> What's the name of the cron script?" User: "NotATrumpet.ksh" DBA: "The NotATrumpet.ksh script sets DBPATH to the old backup server explicitely after running the environment setup script. That server was replaced 5 years ago!" User: "Well that script's been working fine for 7 years! What did you do to break it now?" Art S. Kagel

All We changed the behaviou of connecting via the group as part of the ER/HDR logic that we put into 9.4 so that it would ensure that the 'primary' server would be the one that we connected to any time that we connected to the group. Made the change in both client->server connection logic and in distributed transactions connection logic. If you want to use this technique, you might also want to consider setting INFORMIXCONTIME down low as well so that you don't end up waiting too long on a primary server that isn't there. M.P. "Art S. Kagel" <kagel@bloomberg.net> wrote in message news:441F2D37.6030902@bloomberg.net... > Obnoxio The Clown wrote: > > Karl Ostner said: > > > >>Joachim, > >> > >>you can do it this way: > >> > >>sqlhosts file: > >>myServer group - - > >>myServer1 onsoctcp myHost1 myPort1 g=myServer > >>myServer2 onsoctcp myHost2 myPort2 g=myServer > >> > >>setup HDR pair using myServer1 and myServer2. > >> > >>for your client, set INFORMIXSERVER=myServer > > > > > > That is documented to work as far as ER is concerned, but TFM does not > > explicitly say that it's OK for application use. I would love this to work > > for everything, can someone confirm whether it's a documentation issue or > > whether it's not supported for application use. > > > > It works in all applications with or without ER running. We began to use > this when DBPATH was broken in CSDK 2.60 or so (forget the release) and have > never wanted to go back. It's much more elegant and the DBAs have control > over the failover cascades. With DBPATH you're at the user's mercy: > > User: "The primary server crashed and I can still connect to the database > with dbaccess through the backup server. Why isn't my application connecting?" > > DBA: "What's the app?" > > User: "We just run flugelhorn.exec!" > > DBA: "Hmm, flugelhorn.exec works for me!" > > User: "Well it doesn't work out of the cron script that starts it up hourly!" > > DBA: "<sigh> What's the name of the cron script?" > > User: "NotATrumpet.ksh" > > DBA: "The NotATrumpet.ksh script sets DBPATH to the old backup server > explicitely after running the environment setup script. That server was > replaced 5 years ago!" > > User: "Well that script's been working fine for 7 years! What did you do to > break it now?" > > Art S. Kagel

This is a documentation issue. It'll take sometime to get this info into documentation. cheers, Keshav.