TRANSFER-CONTAINER

This statement sets the size of the transfer container.

Definition

A lower-level DBH option of STORAGE-SIZE

Function

When SQL access plans are processed, SQL scans are produced. These are subareas of an evaluation rule for an SQL statement. During the processing of CALL DML applications, inquiry and response areas are requested for each logical file by means of the OPEN statement.

The SESAM/SQL DBH reserves the above areas in the transfer container, where they are available for further processing.

You use the DBH option TRANSFER-CONTAINER to set the size of the transfer container. The size of the transfer container is specified in units of 1 Kbyte.

The storage space requirements for the transfer container depend on the maximum number of concurrent scans or logical files in existence and their question-and-answer requirements.

You can adjust the values of the option during the DBH session by means of the MODIFY-STORAGE-SIZE administration statement (see "MODIFY-STORAGE-SIZE").

TRANSFER-CONTAINER

= *STD / *PARAMETERS(...)
	*PARAMETERS(...)
		|	INITIAL = 64 / <integer 64..1000000>
		|	,MAXIMUM = 16000 / <integer 64..1000000>

Operands

TRANSFER-CONTAINER = *STD

The default values for the size of the transfer container are described under *PARAMETERS(...).

TRANSFER-CONTAINER = *PARAMETERS(...)

Changes the size of the transfer container.

INITIAL = 64 / <integer 64..1000000>
Sets the size of the transfer container at the beginning of the DBH session. The default is 64 Kbytes.

The initial value for TRANSFER-CONTAINER is compared to the initial value of SUBORDERS. This results in the following minimum value for the initial value of TRANSFER-CONTAINER:

(initial value of SUBORDERS + x) * 4 [Kbytes]

The following applies to x:

• in the independent DBH:

x = 1 + 2 * min(10, [SQL-DATABASE-CATALOG/4]) + 4 * ([THREADS+10]/10)

• in a linked-in DBH: x = 3

MAXIMUM = 16000 / <integer 64..1000000>
Defines the maximum size which the transfer container may reach. The default is 16000 Kbytes.

If the maximum value is smaller than the specified value for INITIAL, then the value of MAXIMUM is adjusted according to the value of INITIAL.

The maximum value for TRANSFER-CONTAINER is also compared to the maximum value of SUBORDERS in the same manner as for the initial value. This results in the following maximum value for TRANSFER-CONTAINER:

(maximum value of SUBORDERS + x) * 4 [Kbyte]

The following applies to x:

• in an independent DBH:

x = 1 + 2 * min(10, [SQL-DATABASE-CATALOG/4])

• in a linked-in DBH: x = 3

Information on the transfer container

You can obtain information on the transfer container and its extensions from the operational statistics of the SESAM/SQL monitor SESMON.
You will find information in the “SYSTEM-INFORMATION” form (see "DBH form SYSTEM INFORMATION") on the size of the container and its extensions.

The “ Performance” manual describes the cases in which it makes sense to modify the container size at the next DBH startup.