6.3.12 Determining the memory requirement for executing the adbmodarea command

When the adbmodarea command is executed, the HADB server uses the type of memory described in this subsection. Determine the requirement for each type of memory.

■ Shared memory

Process common memory (PROC_MODASZ)
Real thread private memory (RTHD_MODASZ)

■ Process memory

Heap memory (MODA_MEM)

Organization of this subsection

(1) Determining the process common memory requirement (for executing the adbmodarea command)
(2) Determining the real thread private memory requirement (for executing the adbmodarea command)
(3) Determining the heap memory requirement (for executing the adbmodarea command)

(1) Determining the process common memory requirement (for executing the adbmodarea command)

Use the following formula to determine the process common memory (PROC_MODASZ) required for executing the adbmodarea command.

Formula (kilobytes)

PROC_MODASZ = MODA_ROWS + MODA_CTL + MODA_DBH + PROC_AUDINFSZ^# + 8

#

Add this value when the audit trail facility is enabled.

Explanation of variables

MODA_ROWS

Determine the value as explained in (a) Determining the variable MODA_ROWS.
MODA_CTL

Determine the value as explained in (b) Determining the variable MODA_CTL.
MODA_DBH

Determine the value as explained in (c) Determining the variable MODA_DBH.
PROC_AUDINFSZ

Determine the value of the variable PROC_AUDINFSZ according to (r) Determining the variable AUDINF in (3) Determining the process common memory requirement (for starting the HADB server) under 6.3.3 Determining the memory requirement for starting the HADB server.

(a) Determining the variable MODA_ROWS

Use the following formula to determine the value of variable MODA_ROWS.

Formula (kilobytes)

MODA_ROWS = ↑ (256 x row_cnt) / 1,024 ↑

Explanation of variables

row_cnt: Number of rows in the dictionary table SQL_DBAREAS

(b) Determining the variable MODA_CTL

Use the following formula to determine the value of variable MODA_CTL.

Formula (kilobytes)

MODA_CTL= 
    8,192 + MODA_REQ + ↑ ( (8 x row_cnt)
    + (64 x (bdev_num_new + bdev_num_alloc))
    + (8 x bdev_num_area) + (256 x bdev_num_file)) / 1,024 ↑

Explanation of variables

MODA_REQ: See the description of the variable MODA_REQ in (2) Determining the real thread private memory requirement (for executing the adbmodarea command).
row_cnt: Number of rows in the dictionary table SQL_DBAREAS
bdev_num_new: Number of new block special files to be allocated
bdev_num_alloc: Number of already allocated block special files
bdev_num_area: Number of DB areas in which block special files are allocated
bdev_num_file: Total number of DB area files in DB areas for which block special files are allocated

(c) Determining the variable MODA_DBH

Use the following formula to determine the value of variable MODA_DBH.

Formula (kilobytes)

[Figure]

#: If you add or expand multiple DB areas, determine the value for each DB area. Then, add up the determined values.

Explanation of variables

add_dbarea_file_num: Number of DB area files added when DB areas are added or expanded by using the adbmodarea command
add_dbarea_file_num_all: Total combined number of existing DB area files and DB area files added by expansion of DB areas

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(2) Determining the real thread private memory requirement (for executing the adbmodarea command)

Use the following formula to determine the amount of real thread private memory (RTHD_MODASZ) required to execute the adbmodarea command.

Formula (kilobytes)

[Figure]

Explanation of variables

MODA_REQ

Use the following formula to determine this value.

[Figure]

bdev_num_new

Number of new block special files to be allocated

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(3) Determining the heap memory requirement (for executing the adbmodarea command)

Use the following formula to determine the heap memory (MODA_MEM) required to execute the adbmodarea command.

Formula (megabytes)

[Figure]

Explanation of variables

bdev_num_new: Number of new block special files to be allocated

Important

When you use the adbmodarea command to add or delete a DB area, the memory requirements listed below change. Therefore, estimate them again.

Global buffer page requirement (variable SHM_BUFGLOBAL)

See (2) Determining the global buffer page requirement (for starting the HADB server) in 6.3.3 Determining the memory requirement for starting the HADB server.
Process common memory requirement (variable BUFGLOBAL)

See (3) Determining the process common memory requirement (for starting the HADB server) in 6.3.3 Determining the memory requirement for starting the HADB server.

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