Re: Experience with large tables using Online

There are some annoying bug in 5.01. The worst I have found is with tbtape. 1) there is no way to verify an archive, might be good might be trash, who knows. 2) There is a serious problem with performing level-0 archives while the engine is on-line. It may not backup all pages to tape. This is because each page has a time-stamp of the last update or last archive or both (I'm not sure which), but this time-stamp can go negative at times which are skipped by a level-0 archive. There is ONLY 2 work arounds. A) Always perform 2 level-0 archives back to back (Informix told me this but I don't know how to restore both) and keep both tapes. This method is not absolutely secure since an active system could cause some pages to be left off both tapes. Correct me if I'm wrong about this. B) Go into quiescent mode and do 2 level-0 archives and only keep the the second. The first archive could be to to /dev/null for speed sake, but you still have to be down during the entire archive process, YUCK. There is also a problem with using temp tables. Apparently, when the engine drops the temp table, especially within a transaction, sometime the engine will attempt to drop the wrong table (YIKES). There is an internal trap to prevent the worst, but the engine comes down as a result. I have had to use perminent temp tables and delete contents each time they are needed (very slow). The last thorny bug only occurs with small tables with a lot of insert and delete activity, after a while you get a -245 error (ISAM error 103). When this occurs, the only fix is to unload, drop and re-load the table. I have looked for help an this problem, but no one seems to know any better work arounds. Using UPDATE STATISTICS more frequently helps this problem, but creates an even uglier concurrency problem (locks on the table AND on some system catalogs). My company is currently trying to decide whether to upgrade to 7.x or switch to a different RDBMS vendor all together. These bugs, and others, have created a serious image problem for my company and the complaints are primarily due to Informix bugs that cause down time and data loss. What is one to do? rmcall@on-ramp.ior.com brford@xmission.com (Russ Ford) wrote: >We are currently running Informix Online 5.01 on an NCR 3450 platform OS >2.01.01. We are looking at implementing a corp table which would contain >about 10G of data and index space. Are there any limitations to the >table size in Online 5.01? I know 7.1 would probably be better for this >but we have some severe time constraints. Anyone have any experience with >large tables like this in 5.01? What limitations are we facing working with >5.01? Thanks. >Russ Ford >brford@xmission.com -------------------------------------------------------- Rob McAllister rmcall@on-ramp.ior.com Spokane, WA "On all good programmers a little core must dump"