Re: Replication Question ~ Answered: amber (solid confidence) — Only a reply survives in the archive (original question by Rob Prop is quoted, not archived separately); it gives a real, specific answer about ER's default timestamp-based collision resolution and hybrid conflict resolution via stored procedures, but the original asker never confirms it solved their problem.

Advisory only.

At 07:14 AM 1/7/98 +1300, Peter Tashkoff wrote: }Rob }I was not actually intending to answer you question as we do not use Enterprise Replication at this site. We have our own trigger based multi-way replication which we built prior to the availability of CDR. (And have only upgraded to 7.23 last week). But since no-one who is actually using it appears to have replied to you, then here is my opinion. }My understanding , having reviewed the documentation, is that the purpose of ER is to allow multi way continuous data replication at a table level. }IE you do not have to copy the whole database, just the bits you want. }IE, yes to your question, if you are wanting to synchonise data between 2 or more *informix* databases then you do not have to buy a third party product, ER will do the job for you. }ER works off the transaction logs and as such does not affect user response on the operational databases. }I suggest to you that you review the documentation and give it a go. }Although ER has a number of methodologies for resolving collisions, where possible if you handle these in your business rules you will save yourself a lot of strife. If each office is only accessing it's own dataset then I do not think that you will have any problems. }I am not sure whether the resolution of ER goes as far as a column level or just row level, IE, if someone updates customer name, while someone on another site simultaneously updates customer address, (both attributes in this hypothetical case of customer) is this a collision or not? }Perhaps someone who is actually using ER could answer. }Cheers Yes there a some people using ER.... The default collision resolution is timestamp. Which ever row has the later time stamp would win. However you can define a hybrid conflict resolution using stored procedures. If each site only operates on its own set of rows, then the instances of collisions should be quite small, and therefore ER a good solution. My concern would be running this over a dial-up..... Jon } } } } }Peter Tashkoff <tashkop@iname.com> }Zespri International Limited Std Disclaimers Apply }All rights reserved. No party may use this document to vilify another. } }Zespri New Zealand Kiwifruit, The World's Finest } } }>>> Herve Delattre <herved@worldnet.fr> 6/01/98 21:33:44 >>> }Take a look at Praxis International OmniEnterprise. }http://www.praxisint.com } }Regards, } }Herve Delattre } } }Rob Prop <rprop@concepts.nl> wrote: } }>I have a question regarding Data Replication. One of our clients has 2 }> offices in 2 different cities. They want to know whats the best }>solution to set up their information system. The software they want to }> use is a system we developed in 4GL. They really want one central }>database. Both offices use (including insert and update) the same }>database, but other datasets. (Normally each office only uses it's }> own data). Their question was: Can we set a database server in each }>office and use replication to update the databases with High }>Availability Data Replication (HADR). My answer was NO !! }> What I know of data replication is that only one server can be updated, }> the other one is readonly. It also isn't wise to use HADR over }> telephone (ISDN or not) lines. They wanted this because when one server }> fails they have the possibility to work on the other. They also wants }>to keep telephone bill as low as possible. }> }> My questions are: }> - Does anyone have a solution ? }> - Can this be done with Enterprise Replication ? }> - Is it possible to synchronise the databases at night ? }> - Is it wiser to set up 2 different env. with a backup on the }> remote machine ? }> - Which software do I need, can I use OWGS or does I need ODS ? }> - Do I need exra software (for the replication etc.) ? }> }> Thank you very much in advance, help me I'm stuck !!! }> } } } ----------------------------------------------------------------------- Jon C. Vemo jon@etcscan.com Database Administration Deluxe Payment Protection Systems/SCAN Bothell, WA (425) 489-1120 -----------------------------------------------------------------------