4.3.3 Estimating memory requirements during execution of the adbidxrebuild command

The following table shows the formula for calculating the amount of memory required when the adbidxrebuild command is executed.

Table 4‒5: Memory requirement determinations (during execution of the adbidxrebuild command)

No.	Memory type		Formula (megabytes)	Related server definitions
1	Shared memory	Shared memory management area	100	None
2		Global buffer page	dbarea_num × 1,024	adbbuff operand
3		Process common memory	1,024 + max_users + GBUF	adb_sys_proc_area_max operand adbbuff operand
4		Real thread private memory	512 + SORTBUF + BLKBUF	adb_sys_rthd_area_max operand
5	Process memory	Heap memory	1,024 + sort_rthd × 0.5	None

Explanation of the variables

dbarea_num

Number of data DB areas

If this value cannot be estimated, use the combined total number of tables and indexes that will be defined.

max_users

Value specified for the adb_sys_max_users operand in the server definition

GBUF

Global buffer

Assume 20 megabytes for each 400 megabytes of the global buffer page size calculated in No. 2.

SORTBUF

Sort buffer

Use the following formula to determine the value.

Formula (megabytes)

sort_buff_size

Value specified for the adb_idxrebuild_sort_buff_size index rebuild option

sort_rthd

Use the following formula to determine the value.

value-specified-for-index-rebuild-option-adb_idxrebuild_rthd_num - 1

BLKBUF

Buffer for creating indexes

Use the following formula to determine the value.

Formula (megabytes)

buff_blk_size

Assume 4,096.

buff_blk_num

Value specified for the adb_idxrebuild_buff_blk_num index rebuild option

scan_rthd

Use the following formula to determine the value.

↓(value-specified-for-index-rebuild-option-adb_idxrebuild_rthd_num - 1) ÷ 2↓

dividx_rthd

Use the following formula to determine the value.

value-specified-for-index-rebuild-option-adb_idxrebuild_rthd_num - 1

txt_sort_buff_size

Value specified for the adb_idxrebuild_txt_buff_size index rebuild option

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