Re: informix vs oracle

mail@markscranton.com wrote: > To all - > > I just returned from Mexico and Tokyo, and have some good news for the > Informix faithful...In Mexico, Informix is still leading Oracle in > market share. No - I don't know the percentages. We will continue to > visit Mexico clients to support these accounts, and grow new business. > > In Brazil, a very large Informix customer is starting a migration to > Informix from Oracle. This is very good news. > > Also, in Tokyo, we are securing consulting resources to help one of > Japan's largest Informix customers migrate some of their systems from > Oracle to Infomix as well. > > By the way, I'm not looking to compare "how many have migrated from > Informix to Oracle" over the last couple of years versus the inverse. > We are very aware of those situations. I just felt this was info the > Informix community should be aware of to help further the cause. > > Thanks, > Mark Scranton > > utkanbir wrote: > >>Hi Gurus , >> >>After 7 years with informix and 2 years with oracle , these are my > > own > >>comments about them. All the comments / corrections are wellcomed: >> >>1. backup / restore >> >>informix : the backup set is a complete object . It does not depend >>anything .It can be used as the only object in order to do restore. >> >>oracle : lots of things must be considered. You must know what you >>do. 'I just want to backup and restore my db ' is not enough. To do > > a > >>complete restore of the db , first it is necessary to copy all the >>files to a backup location (including datafiles,control files, undo >>and redo log?no be careful if you want to recover the db after > > copying > >>files back , you need current logs so backing up redo logs are not >>necessary . On the other hand copying entire datafiles before any > > type > >>of incomplete recovery is very important . (in order to restore a db > > , > >>copying the files once again huh...) And dont expect the ontape -r >>command's lovely message: do you want to backup the current logs? No >>such a thing exist....) >> >>If someone who only knows oracle ,doesnt know aynthing about the > > other > >>databases , this backup method can be the best one. But if you know >>the other databases restore backup methods, oracle method is much > > more > >>difficult and complex. >> >> >>2. Parallel query >> >>oracle : parallel query bypasses the buffer cache. it directly reads >>data from the disk into the user process's pga memory . It also does >>not check whether a block is cached in memory or not , it reads the >>disk every time. So same parallel query executed several times makes >>the same amount of disk io . >> >> >>On the other hand , parallel query architecture is more flexible than >>informix. It does not depend on tablespace number / partition . And >>parallel dml , parallel optimizer hints are very rich. (last veison > > of > >>informix i used is 9.2 so may be informix have some improvments which >>i dont know) >> >> >> >>3. Nologging operations: >> >> >>In oracle , it is possible to do certain operations without > > generating > >>redo log . These are called unrevorable operations : >> >>create table test nologging as (select * from dual)>> >>insert /*+append */ into a select * from dual >> >>these operations is not logged in redo logs so cant be reovered. >> >>But the drawback of such an operation is , if you have to recover the >>db server or datafile by using redo logs , the entire table becomes >>useless. Not >>only these insert statements are invalid but also the whole table. >> >>4. multi-versioning >> >>oracle has no dirty read concept but instead multi-versioning . So if >>session a updates data , session b see the previous version of the >>recods .But this can also happen for a long running queries!Although >>no updates take place , lots of different versions can be put in >>memory especially if your db is a datawarehouse type. >> >> >>Kind Regards, >>hope Is there a source for this information that can be verified or this just something you heard in a cantina? -- Daniel A. Morgan University of Washington damorgan@x.washington.edu (replace 'x' with 'u' to respond)

After working several years with Informix, we are planning to migrate to Oracle because the lack of support in Mexico. Just a couple of weeks ago we were going to migrate from one version to another so we asked Informix people to help us, and after a brief meeting, their conclusion was that "we knew more than them"..... I think Informix is a great database, but the lack of support it's a shame. I totally disagree with Mark because at least several companies in Mexico that have SAP with Informix, are planning to migrate to Oracle or Sql server. Also SAP has announced that they are not going to support Informix for Netweaver. And what about documentation ? There are only very old books about Informix compared with lots of documentation about Oracle. I think IBM is not doing a good job in supporting and positioning Informix. If IBM bought Informix -- Message posted via http://www.dbmonster.com