Hi Emmanuel, Actually, I misunderstood what you were saying. Yes, I think I need to put triggers on my database tables. I just want to make sure that my idea putting triggers to my database tables directly is correct or not. From now it is clear.
Thanks a lot! On Wed, Dec 3, 2008 at 9:36 PM, Emmanuel Cecchet <[EMAIL PROTECTED]>wrote: > 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 > -- 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)
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