Connection module parameters

DBCON require various parameters in order to fulfill its functions. The DBH name and the configuration name are important connection module parameters. They assign the application program linked to the connection module to a DBH and a configuration. Beyond that, there are various other DBCON configuration parameters

TIAM, DCAM and UTM applications

Connection modules for TIAM and DCAM applications that work with the independent DBH (DBCON) are usually parameterized through the application program's configuration file (see section “The configuration file”).

The user enters the connection module parameters in the configuration file and assigns them before the application program linked with the connection module is started. The parameters are then transferred to the connection module in the course of the start procedure.

In cases in which the linked-in DBH is used, where the DBH is directly linked with the application program, the DBH name and the configuration name are contained in the DBH's configuration file as DBH start parameters (see section “The configuration file for DBH start parameters”). No configuration parameters are used in connection with DBCONL.

The list below shows the connection module parameters for TIAM, DCAM and UTM applications, in each case in alphabetical order.

• It begins with connection module parameters used in connection with TIAM, DCAM and UTM applications.

• These are followed by connection parameters that are only used in connection with both DCAM and UTM applications or with DCAM applications only. Connection module parameters that apply only to UTM applications are described in section “Starting a SESAM/SQL UTM application”.

All parameters are DBCON parameters.

Connection module parameters for TIAM, DCAM and UTM applications

Spaces are not permitted in parameter lines.

CCSN=ccs-name	Coded character set with which the user program works.
ccs-name:	Name of the coded character set as defined in BS2000 (system component XHCS) or *NONE if no coded character set is to be sepcified for the user program. Default: *NONE If a coded character set is used (CODE-TABLE ccs_name clause in the CREATE CATALOG or ALTER CATALOG statement), the database’s CCS name must match the user program’s CCS name when the user program accesses the database. User program accesses with CCSN=*NONE or accesses by user programs from SESAM/SQL < V5.0 are rejected with SQLSTATE. This check does not take place for the utility statements CREATE/ALTER CATALOG, CREATE/REFRESH REPLICATION and RECOVER CATALOG [SPACE]. If no CCSN was specified for the database, this check does not take place either.
CNF=k	Name of the configuration in which the application program is to operate
k	A..Z, 0..9, ? Default: ?
DIAG-DUMP=(diag)	Criterion for the generation of a diagnostic dump
diag:	{SQLSTATE=state|STATUS=status} state: SQLSTATE with class and subclass (5 bytes);  status: CALL DML status with subnumber (4 bytes) SQLSTATE can be partially qualified by entering “***” for the  subclass. CALL DML status can be partially qualified by entering “**” for the  subnumber. The first time the relevant error message is issued (SQLSTATE or  CALL DML status), a user task dump will be output (see the  “Database Operation” manual)
ISOL-LEVEL= level	Default value for the isolation level of SQL transactions. Only effective in SQL applications.
level:	{READ-UNCOMMITTED | READ-COMMITTED | REPEATABLE-READ | SERIALIZABLE} Default: SERIALIZABLE Valid for all transactions of the ESQL application program if the isolation level was not specified by the appropriate SQL statement in the program. This parameter is only evaluated by TIAM and UTM applications.
NAM=x	Name of the DBH with which the application program is to work
x:	A..Z, 0..9, ? Default: ?
NOTYPE	The message SESAMxx not available ... is suppressed
NVT	The application can only run locally and it can only communicate with the DBH entered in the NAM parameter. This also applies when SESDCN is loaded.
PREFETCH-BUFFER=buffersize	Size in KB of the buffer used for the prefetch. Value range: 0 <= buffersize <= 4096 This parameter is only evaluated by TIAM and UTM applications.
PRIO-CHECK=t	Interval in seconds between two consecutive checks of the BS2000 task priority of the application program. 10 <= t <= 3600 Default: 300
PRIO-CHECK=OFF	The check of the BS2000 task priority of the application program will be deactivated following the first check.
SQLOPT-KEEP-JOIN- ORDER={YES | NO}	Default: NO
NO	The SESAM/SQL optimizer decides on the order of the join operands in the case of multiple joins.
YES	For the order of the joins, the SESAM/SQL optimizer keeps as closely as possible to the order of join operands defined in the SQL statement. This applies for explicit joins (e.g. table_1 JOIN table_2 ON search_condition).
SQLOPT-PREFERRED- JOIN-METHOD={SORT- MERGE | NESTED- LOOP | NONE}	Default: NONE
NONE	The SESAM/SQL optimizer decides on the join algorithm.
SORT-MERGE NESTED_LOOP	The SESAM/SQL optimizer uses the specified join algorithm as far as possible.

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Use these two SQL notes with care! They apply for all applications which work with this configuration file.However, pragmas and annotations of the SQL statements have priority over these SQL notes of the configuration file.

TRACE,TYPE=type	Logging of the call or message trace is activated when the application program starts.
type:	{CALL|MSG | (CALL,MSG)} [,OUTPUT={SYSOUT | SYSLST | (SYSOUT,SYSLST)}]  Default for output (OUTPUT): SYSLST Refer to the “Database Operation” manual for further information on call and message tracing.

DCAM- and UTM-specific connection module parameters

PUF=p	Maximum message length of DCAM or UTM applications in bytes 1 <= p <= 64000 Default: 4096 A message may be: the request (statement) of an application program to a SESAM/SQL DBH the response of a SESAM/SQL DBH to the application program Since the length of SQL messages is difficult to estimate, we recommend you choose the value 64000 for p for applications with SQL statements.
TOTAL-APPL=a	Maximum number of SESAM/SQL user applications in the configuration (this only applies to applications that do not operate in distributed mode) 1 <= a <= 128 Default: 64
TOTAL-USERS=u	Maximum number of SESAM/SQL user in the configuration (this only applies to applications that do not operate in distributed mode) 1 <= u <= 16000 Default: 128

The TOTAL-APP and TOTAL-USERS parameters apply to the entire configuration. The first application started determines the size of the user pool on the basis of these parameters. Any applications that are started subsequently simply make use of this pool. Any parameters specified in these applications are ignored.

DCAM-specific connection module parameters

NAME-APPL=appl	The name of the DCAM application.
appl:	1-8 printable characters of any kind Default: TSN=tsn
REQUEST-USERS=r	The maximum number of concurrent asynchronous calls per task in DCAM applications. 1 <= r <= 128 Default: 7
START	Cold start for DCAM applications. Default: warm start