To reduce loading times or main-memory requirements, you can make use of the possibility to load SESAM LLMs via DSSM as subsystems.
Loading SESAM-LLMs as subsystems
SESAM delivers several LLMs that can be loaded by the dynamic subsystem management facility (DSSM) of BS2000. Hence several tasks in BS2000 can use these modules shared.
Some communication modules and parts of SESDCN can be loaded into class 4 memory as subsystems under DSSM with the following command:
/START-SUBSYSTEM SUBSYSTEM-NAME=<SESAM_subsystem_name>, VERSION=<SESAM_product-version mandatory-man-corr>, VERSION-PARALLELISM=*COEXISTENCE-MODE
Specifying VERSION-PARALLELISM=*COEXISTENCE-MODE (coexistence permitted) enables you later to start multiple correction statuses of SESAM/SQL in parallel, thus facilitating the migration to a new correction status during ongoing operation. If you do not want this, you can use the default value VERSION-PARALLELISM=*NONE.
The VERSION-PARALLELISM=*EXCHANGE-MODE operand is not supported by SESAM/SQL.
Example
/START-SUBSYSTEM SUBSYSTEM-NAME=SESKOM,VERSION=9.1A00,-
/ VERSION-PARALLELISM=*COEXISTENCE-MODE
DSSM controls the dynamic loading, initialization, suspension, continuation and termination of the subsystems (see the “Subsystem Management (DSSM/SSCM)” manual).The START-SUBSYSTEM command is described in the “Commands” manual.
Parallel use of multiple correction statuses
With SESAM/SQL-Server, several correction statuses can be used in parallel. If one or more subsystems of SESAM/SQL are already loaded when a new correction delivery status is loaded, the SESAM subsystems do not automatically load the new correction delivery status.
If you have started the systems with coexistence permitted as described in the section “Loading LLMs as subsystems”, you can start the subsystems with the new correction statuses parallel to the running subsystems using START-SUBSYSTEM without impairing database operation, e.g.
/START-SUBSYSTEM SUBSYSTEM-NAME=SESKOM,VERSION=9.1A10,-
/ VERSION-PARALLELISM=*COEXISTENCE-MODE
Subsequently all newly started SESAM/SQL tasks use the new subsystems. When all SESAM/SQL tasks which were not yet connected with the “old” subsystems have been terminated, the subsystems with the old correction status can be terminated.
As an alternative to the process described above you can terminate all tasks which are attached to the SESAM subsystems. You must then also stop the subsystems with the
/STOP-SUBSYSTEM SUBSYSTEM-NAME=<SESAM_subsystem_name> command.
Database operation will then be interrupted. The SESAM subsystems must then be restarted using the command:
|
SESAM/SQL can then restart the tasks. These tasks now load the new correction status (see also the section “Specifying the correction status with the start command”).
Lists of the SESAM/SQL share modules
The tables below list the available SESAM/SQL share modules. The column entitled “DSSM subsystem” indicates the subsystems into which the LLMs are grouped when loaded with DSSM.
In the LLM names, “xx” is a placeholder for the digits in the version number of SESAM/SQL.
LLM name | Meaning | DSSM subsystem |
SECDNxx | SESDCN share module | SESKOMMD |
Table 3: Share module of SESDCN, the distribution component for distributed processing with SESAM/SQL-DCN
LLM name | Meaning | DSSM subsystem |
SECLAxx | Communication LLM for non-distributed processing | SESKOMOD |
SECVAxx | Communication LLM for distributed processing | SESKOMMD |
SERTSxx | SQL runtime system | SESSQLRT |
Table 4: communication share modules
LLM name | Task types that use the share module | DSSM subsystem |
SEZCSxx | DBH, SESDCN and independent communication in the application program | SESKOM for |
SEJSVxx | DBH and independent communication in the application program | |
SECCSxx | Independent communication in the application program | SESKOM for |
SECSVxx | Independent communication in the application program |
Table 5: Share modules used by several task types