> The VOC file on my UV/NT box is set up as a type 3 file .. I'm thinking that > that's NOT the right type for the file, but I'm not sure yet ..
The descriptions of the hashing processes refer to character types to make them easier to understand. The algorithms actually aren't interested in character types but look at only a restricted number of bits of each byte. So, don't be fooled into thinking that character type is all that important. Hashing is totally a statistical guessing game. Whichever static file type you choose, the hashing process takes your record ids, looks at specific bits from a limited number of characters from one end as specified by the hashing algorithm, applies whatever the calculation is that the algorithm does to make a big number, divides the result by the file's modulo and uses the remainder plus one as the group number. The actual record ids present may make an apparently wrong choice of algorithm actually work better than one that looks as though it should be better. The VOC file starts life a type 3 because this does give the best distribution for the particular records in it. As soon as you have added your stuff on top of these, this choice may now be wrong. There is a catch to resizing the VOC. Although you can usually get away with doing it from in the same account, the command processor seems to get a bit confused and be unable to find some records afterwards, probably because it is caching information about the VOC. You need to quit out and re-enter UniVerse. If you are really unlucky, QUIT is on eof the commands it can't find! The safest solution is to make an F-pointer from some other account and do the resize remotely. In teaching UniVerse training courses to people who have moved from other databases I find that they often say that their old system wasn't this complex as they didn't have to worry about file types. Effectively, their previous system used an equivalent to type 18. This works well for most data. The other file types, 2 - 17, allow you to get that last little bit of performance for critical files but take a lot of work to get right. In most cases, type 18 is just fine and it isn;t worth the effort of doing anything better except for files that are critical to the system's performance. Martin Phillips Ladybridge Systems 17b Coldstream Lane, Hardingstone, Northampton NN4 6DB +44-(0)1604-709200 ------- u2-users mailing list [EMAIL PROTECTED] To unsubscribe please visit http://listserver.u2ug.org/
