FAQ

Regarding the FAQ, here are some criticisms and comments: In 6.1, Configuring OnLine: default Transaction high-water marks -- Should be less than 50%, to allow a roll-back. Have enough logs that whatever number you choose is enough for your largest long transaction. 70/80 is not nearly low enough. add number of locks -- depending on your application and the number of users you will have concurrently, increase this. A lot. The max is one quarter million, default is 2,000. I always set mine to be >100,000 and <200,000. Remember, a massive delete (such as can be easily run from SQL) can generate tens of thousands of locks in a hurry. If you run out of locks the index can and will be corrupted. You may have to restore from backup to recover. This will cost you some memory but not much. Number of licenses used -- if you use the SQL user menu to launch another informix application (one you wrote in 4gl, say) the user will have consumed 2 licenses! One for the menu, and one for the application. You can quickly run out of licenses this way. We use a shell script for the front-end user menu and have it run one informix application at a time. Disk Allocation -- store different parts of your database on different spindles on different controllers. For example, store the root db, the log space, the data tables all on *different* disks, and if your bottleneck then becomes controller I/O, run these different disk drives on different controllers. Ensure your tables are in contiguous disk space by a) creating each table in a specific dbspace, which is linked to a specific disk partition. You can choose which partition receives which data, and influence where on the disk the data physically resides. Data on the inner sectors are denser than those in the outer sectors, and read faster. b) allocating enough space in 1 extent with the EXTENT SIZE qualifier to the CREATE TABLE command. c) loading each table immediately after creation, before the next table is created, to REALLY put the data in contiguous space. That ought to about do it for now. I'm posting this since I haven't publicly spoken on some of these issues before. I'll be in the UK for the next couple of weeks so don't look for a witty response to flames before then. Tally ho y'all, __________________________________________________________________ | Clem Akins Standard Disclaimers Apply | | Reynolds Metals Co. "Climb High, Cave Deep!" | | Muscle Shoals, Alabama USA cwakins@jabba.rmc.com | |________________________________________________________________|