Keeping Master Files Open on the FOCUS Database Server
The SET SUWEDGE command provides a mechanism for keeping Master Files in memory
on a FOCUS Database Server even though no users are accessing the files. This
enhances performance by eliminating repeated parsing of Master Files on FOCUS
Database Servers that have a large number of users running multiple applications using
different files on the server.
You can specify that a number of files be wedged open, that specific named files be
wedged open, or a combination of both. The maximum number of files that will be wedged
open is 128, regardless of how many you specify.
Syntax: How to Wedge Master Files Open on a FOCUS Database Server
Place one or more of the following commands in the server profile (PROFILE HLI):
SET SUWEDGE = {n|ddname} [, {n|ddname} ...]
where:
- n
- Is a number of Master Files to be wedged open. You can specify any number, but once
128 files are wedged open, additional files will not be wedged. The default is zero.
- ddname
- Is the ddname of a specific file to be wedged open in addition to the n files specified
by number (if any).
Note: To set both a number of files to be wedged and one or more specific ddnames to be
wedged, you can issue the SET SUWEDGE command multiple times or specify multiple
options in one SET SUWEDGE command. Specific ddnames are not counted in the number
of files specified (as long as the total does not exceed the maximum number of wedged
files allowed). If you specify a number multiple times, the last one specified is the one
used.
Reference: Usage Notes for SET SUWEDGE
- The most improvement in performance is gained by wedging open large Master Files and those used most often in MODIFY applications.
- Master Files are not opened by the SUWEDGE facility until a MODIFY or Maintain procedure that references them is executed.
- If a wedged Master File has a static cross reference to another Master File, only the parent Master File is wedged open when it is used in a MODIFY or Maintain application. A cross-referenced file is only wedged open when it is explicitly referenced in a MODIFY or Maintain procedure.
- All Master Files that participate in a COMBINE structure are opened when the COMBINE structure is referenced in a MODIFY application. Similarly, all files participating in a MAINTAIN procedure are opened when the Maintain procedure is executed.
- Using the SUWEDGE facility causes increased use of memory on the FOCUS Database Server.
- The maximum number of Master Files that can be open at one time on a FOCUS Database Server is 256, regardless of wedging.
- Files whose names begin with a number cannot be wedged open by explicitly specifying their names in the SET SUWEDGE command.
- If you specify a number of files to be wedged open and you issue a TABLE request on the FOCUS Database Server, the FOCUSSU file will be wedged open.
- You can see which files have been wedged open by examining the HLIPRINT file. The first OPN command listed for a wedged file will be associated with the user ID suwedge.
Example: Wedging Files Open on a FOCUS Database Server
The following commands wedge open any three FOCUS data sources plus the EMPLOYEE
and CAR data sources:
SET SUWEDGE = 3
SET SUWEDGE = EMPLOYEE
SET SUWEDGE = CAR
or
SET SUWEDGE = 3
SET SUWEDGE = EMPLOYEE, CAR
or
SET SUWEDGE = EMPLOYEE, CAR
SET SUWEDGE = 3
or
SET SUWEDGE = 3, EMPLOYEE, CAR