6.3.6 Operands related to lock
- 11) pd_fes_lck_pool_size = front-end-server-lock-pool-size
<unsigned integer> (KB)- 32-bit mode: ((1-2000000))
- 64-bit mode: ((1-2000000000))
- Specifies in kilobytes the size of the shared memory area to be used for locking by a front-end server.
- Specification guidelines
- In the 32-bit mode, the amount of lock pool space required for six lock requests is 1 KB.
- In the 64-bit mode, the amount of lock pool space required for four lock requests is 1 KB.
- Use the following formula to determine the value of this operand:
(a + b)
c
(KB)
- a: Total number of transaction lock requests to be executed concurrently by the front-end server. The number of lock requests depends on the SQL. For details about how to determine the total number of lock requests, see E. Determining the Number of Locked Resources.
- b: (value of pd_max_users + 3)
(value of pd_max_access_tables + 4) - c: Use 6 and 4 for 32- and 64-bit modes, respectively.
- Tuning the specified value
- See the usage rate for the locked resources management table (%OF USE LOCK TABLE) displayed for the front-end server in the statistical information on system operation by the statistics analysis utility. If the maximum usage rate equals or exceeds 80%, it is recommended that the operand's value be increased in preparation for future database expansion. If the maximum usage rate does not exceed 10%, it is recommended that the operand's value be decreased to conserve shared memory space.
- Note
- If the value specified for this operand is too small, an SQL may return an error.
- 12) pd_lck_hash_entry = lock-pool-hash-entry-count
<unsigned integer>((0-2147483647))- Specifies the number of hash table entries to be used in the lock pool. According to the value specified here, HiRDB allocates a lock pool in the shared memory for the unit controller.
- Specification guidelines
- Normally, omit this operand.
- Consider specifying a value for this operand in the following cases:
- If you do not wish to change the shared memory size if possible when upgrading to Version 06-02 or a newer version, specify 11261. In this case, the same number of hash entries is allocated as in the older version, and the hash table size inside the lock pool remains the same as before.
- Specifying for this operand a value greater than the recommended value may improve performance. However, specifying a value greater than variable a described in Determining the recommended value does not improve performance over a case in which a is specified.
- Operand rules
- If 0 is specified for this operand or if this operand and the pd_lck_hash_entry operand of the server common definition are omitted, HiRDB computes a recommended value for each server. For details about recommended values, see Specification guidelines for the pd_lck_hash_entry operand.
- If a non-zero value or a non-prime number is specified for this operand, HiRDB assumes that the largest prime number not exceeding the specified value has been specified.
- Note
- If the value specified for this operand is too small, hash entry shortage may occur, resulting in performance degradation. If this operand is omitted, neither hash entry shortage nor performance degradation due to hash entry shortage occurs.
- Determining the recommended value
- For details on the recommended values, see Determining the recommended value for the pd_lck_hash_entry operand of the server common definition.