This was implemented mainly as a test to see if ISAM access in a non-LOKSER environment could be significantly improved by not bothering to place a lock on the IDX "rock" when performing an ISAM operation. In theory, this simulates the way it works under AMOS when LOKSER is not on. In our experience so far, it does not seem to have that much of an effect. It was implemented as a file-oriented switch rather than a global option (like OPTIONS=ISAM_IDXLOK) because it is probably only practical, if at all, with files that are only going to be scanned and not updated.

WARNING: using this option with a file that is being updated may lead to IDX corruption, unless you have some other mechanism in place to make sure two users are updating the IDX at once!

History

2006 March, A-Shell 4.9.952:  In ISAM 1.0, when ASFLAG,32 is used to turn off all locking of the IDX file, if an error other than key-not-found (erf 33) occurs, A-Shell now retries the operation after doing a normal index lock. The theory here is that it may make it safer to use the no-lock mode in certain read-only situations (mainly in a peer-to-peer LAN environment) where normal locking has a high overhead and speed is the main consideration.