Thread Pool

enable_thread_pool

Parameter description: Specifies whether to enable the thread pool function. This parameter is a POSTMASTER parameter. Set it based on instructions provided in Table 1.

Value range: Boolean

• on indicates that the thread pool function is enabled.
• off indicates that the thread pool function is disabled.

Default value: off

thread_pool_attr

Parameter description: Specifies the detailed attributes of the thread pool function. This parameter is valid only when enable_thread_pool is set to on. Only the sysadmin user can access this parameter. This parameter is a POSTMASTER parameter. Set it based on instructions provided in Table 1.

Value range: a string, consisting of one or more characters

This parameter consists of three parts: thread_num, group_num, and cpubind_info. The meanings of the three parts are as follows:

• thread_num indicates the total number of threads in the thread pool. The value ranges from 0 to 4096. The value 0 indicates that the database automatically configures the number of threads in the thread pool based on the number of CPU cores. If the value is greater than 0, the number of threads in the thread pool is the same as the value of thread_num. You are advised to set the thread pool size based on the hardware configuration. The formula is as follows: Value of thread_num = Number of CPU cores x 3–5. The maximum value of thread_num is 4096.
• group_num indicates the number of thread groups in the thread pool. The value ranges from 0 to 64. The value 0 indicates that the database automatically configures the number of thread groups in the thread pool based on the number of NUMA groups. If the value is greater than 0, the number of thread groups in the thread pool is the same as the value of group_num.
• cpubind_info indicates whether the thread pool is bound to a core. The available configuration modes are as follows: 1. '(nobind)': The thread is not bound to a core. 2. '(allbind)': Use all CPU cores that can be queried in the current system to bind threads. 3. '(nodebind: 1, 2)': Use the CPU cores in NUMA groups 1 and 2 to bind threads. 4. '(cpubind: 0-30)': Use CPU cores 0 to 30 to bind threads. 5. '(numabind: 0-30)': Use CPU cores 0 to 30 in the NUMA group to bind threads. This parameter is case-insensitive.

Default value: '16, 2, (nobind)'

thread_pool_stream_attr

Parameter description: Specifies the detailed attributes of the stream thread pool function. This parameter is valid only when enable_thread_pool is set to on. Only the sysadmin user can access this parameter. This parameter is a POSTMASTER parameter. Set it based on instructions provided in Table 1.

Value range: a string, consisting of one or more characters

This parameter consists of two parts: stream_thread_num and stream_proc_ratio. The meanings of the two parts are as follows:

• stream_thread_num indicates the total number of threads in the stream thread pool. The value ranges from 0 to 4096. The value 0 indicates that the database automatically configures the number of threads in the thread pool based on the number of CPU cores. If the value is greater than 0, the number of threads in the thread pool is the same as the value of stream_thread_num. You are advised to set the thread pool size based on the hardware configuration. The formula is as follows: Value of stream_thread_num = Number of CPU cores x 3–5. The maximum value of stream_thread_num is 4096.
• stream_proc_ratio indicates the ratio of proc resources reserved for stream threads. The value is a floating point number. The default value is 0.2. The reserved proc resources are calculated as follows: stream_proc_ratio x stream_thread_num.

Default value: '16, 0.2'