4.3.1 Estimating memory requirements during normal operation
The following table shows the formula for calculating the amount of memory required during normal operation.
|
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 + (db_idx × 1,024) |
adbbuff operand |
|
|
3 |
Process common memory |
1,024 + max_users + GBUF |
|
|
|
4 |
Real thread private memory |
rthd_num × 1,074 |
adb_sys_rthd_area_max operand |
|
|
5 |
Process memory |
Heap memory |
1,024 |
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.
- rthd_num: Total number of real threads
-
If this value cannot be estimated, use the number of CPU cores in the machine on which the HADB server was installed.
- db_idx: Size of the data DB area for storing indexes (gigabytes)
-
Substitute the values determined for the following items in Table 4‒1: Formula (DB directory size) in 4.2.1 Estimating the size of the DB directory.
-
Data DB area file for storing B-tree indexes
-
Data DB area file for storing text indexes
-
Data DB area file for storing range indexes
-