option #55

Map Q_NO_LOCK to Q_NO_TLOCK

WSupported on Windows
USupported on Unix
VSupported on OpenVMS
NSupported in Synergy .NET

When system option #55 is set, READS with LOCK:Q_NO_LOCK is automatically mapped to READS with LOCK:Q_NO_TLOCK. This setting enables you to make use of the READS prefetch feature of xfServer (and thus improve performance when doing sequential reads) without modifying your code.

Tip

Because Q_NO_TLOCK uses fewer resources than Q_NO_LOCK and provides similar performance to a READS on a file opened for input, system option #55 will provide performance gains, regardless of whether or not you use the prefetching feature.

Do not use this option if you want to see concurrent changes made by other users, as Q_NO_TLOCK does not guarantee changes will be seen. (See LOCK for more information.)

See READS and SCSPREFETCH for more information about the prefetch feature of xfServer.