Hi Bogon, > Thank you for your reply. > I think that you meant I need to install triggers attached to the > recovery log table. So, whenever the tuple > of the recovery log table is added, the triggers add the old value and > new value to a different new table. > > But, I am not sure how I can reference the old value and new value of > a updated tuple in the original table > from the recovery log table's triggers. > > For example, let's assume that one tuple is added in the recovery log. > Something like this: > update ... ? ? ? | <value1><value2><value3> > > A update trigger in the recovery log table will detect its new insertion. > However, before detecting that insertion, already an original table > has updated, or over-written the old > value. So, how can we fetch an old value even in this scenario? Sorry, > I am not an expertise in a trigger. > > Or, you just meant that I need to install triggers to my > original(working) tables directly? If what you want to track is changes to your database tables, then the triggers have to be fined on your original working tables on the database backends. You should not touch the recovery log tables for any reason. > I could not understand easily how the triggers in the recovery log > table can still have old values > of my working tables, which have already been over-written by a > controller. Thanks a lot. I am not sure to understand what you are really trying to achieve and why you would like to manipulate the recovery log content.
Don't hesitate to clarify if I misunderstood your intent. Emmanuel > On Wed, Dec 3, 2008 at 12:34 AM, Emmanuel Cecchet > <[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>> wrote: > > Hi, > > I wonder if there is some easy way to audit old value and new > value, when a user updates his/her row. > I think I need to insert some trigger to do this in each > backend MySQL, in the worst case. When I look at the recovery > log table, it only keeps new values but now old values. Do you > think that there is some tricky way to put old values > in the recovery log? > > The recovery log just logs SQL statements that update the > database. It does not record any value. > You can retrieve the value that is updated with a trigger by > examining the tuple before and after. You can eventually log the > old value to another table but in that case the trigger has to be > the same on all backends since this is an internal database > mechanism and not something triggered by Sequoia. > Note that Sequoia cannot schedule trigger execution either so you > have to be careful on how you use them to prevent out of order > updates on different nodes. > > Best regards, > Emmanuel > > -- > Emmanuel Cecchet > FTO @ Frog Thinker Open Source Development & Consulting > -- > Web: http://www.frogthinker.org > email: [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> > Skype: emmanuel_cecchet > > _______________________________________________ > Sequoia mailing list > [email protected] > <mailto:[email protected]> > https://forge.continuent.org/mailman/listinfo/sequoia > > > > > -- > 여호와는 네게 복을 주시고 너를 지키시기를 원하며 > 여호와는 그 얼굴을 네게 비추사 은혜 베푸시기를 원하며 > 여호와는 그 얼굴을 네게로 향하여 드사 평강 주시기를 원하노라 > (민수기 6:24-26) > ------------------------------------------------------------------------ > > _______________________________________________ > Sequoia mailing list > [email protected] > https://forge.continuent.org/mailman/listinfo/sequoia -- Emmanuel Cecchet FTO @ Frog Thinker Open Source Development & Consulting -- Web: http://www.frogthinker.org email: [EMAIL PROTECTED] Skype: emmanuel_cecchet _______________________________________________ Sequoia mailing list [email protected] https://forge.continuent.org/mailman/listinfo/sequoia
