Re: usage of the dbexport.

In article <9655@emory.mathcs.emory.edu> mana-s@ascii.co.jp (Manabu Shimohira) writes: > >Hello to networld. > >Is there anybody who can let me understand why the dbexport is not >suitable for database backup, or why I should avoid using dbexport >for database backup. > >I thought the dbexport and dbimport is a handy method for archiving >data with their schema. > >But I can find several caution to not to use dbexport for database >backup (ex. p4-7 in I-SE ADMIN, p5-24 in GUIDE TO SQL TUTORIAL, >p3-113 in I-OnLine ADMIN.. all for v5.0) > >There will be some reason not to use dbexport. I just want to know why. I didn't email this as I'm sure there is some general interest in the topic. The answer has several parts. First, and I think most important, is that logs cannot be applied to a database restored via dbimport. So your backup is a static picture of the database at a particular moment in time. If it is sufficient to restore your system to that point only, then dbexport may be an appropriate choice for backup for you. However, the secondf part is that dbexport takes a long time and locks the database while it does its work. This means that you cannot access any data until the export is complete. Again, if this is acceptable for your application, then dbexport may be the right choice. If you are using OnLine, you probably want to minimize downtime, so the OnLine backup utilities will be more useful, since the allow on-line archiving as well as full restoration from logs. If you are using SE, then you would use a Unix backup utility. Again, if you are not using a log (or don't need to recover xactions from the time of the last backup to the time of the crash), then dbexport may be ok. Bear in mind that it will take longer than a dd (for example) and it will take longer to restore the database, should you need to (again, compared to dd or equivalent). Dave -- Disclaimer: These opinions are not those of Informix Software, Inc. ************************************************************************** The heart and the mind on a parallel course, never the two shall meet. -E. Saliers