Asynchronous I/O Operations
enable_adio_debug
Parameter description: Specifies whether O&M personnel are allowed to generate some ADIO logs to locate ADIO issues. This parameter is used only by developers. Common users are advised not to use it.
This parameter is a SUSET parameter. Set it based on instructions provided in Table 1.
Value range: Boolean
- on or true indicates that generation of ADIO logs is allowed.
- off or false indicates that generation of ADIO logs is disallowed.
Default value: off
enable_adio_function
Parameter description: Specifies whether to enable the ADIO function.
This parameter is a POSTMASTER parameter. Set it based on instructions provided in Table 1.
Value range: Boolean
- on or true indicates that the function is enabled.
- off or false indicates that the function is disabled.
Default value: off
enable_fast_allocate
Parameter description: Specifies whether the quick disk space allocation is enabled.
This parameter is a SUSET parameter. Set it based on instructions provided in Table 1. This function can be enabled only in the XFS file system.
Value range: Boolean
- on or true indicates that the function is enabled.
- off or false indicates that the function is disabled.
Default value: off
prefetch_quantity
Parameter description: Specifies the amount of the I/O that the row-store prefetches using the ADIO.
This parameter is a USERSET parameter. Set it based on instructions provided in Table 1.
Value range: an integer ranging from 128 to 131072. The unit is 8 KB.
Default value: 32MB (4096 x 8 KB)
backwrite_quantity
Parameter description: Specifies the amount of I/O that the row-store writes using the ADIO.
This parameter is a USERSET parameter. Set it based on instructions provided in Table 1.
Value range: an integer ranging from 128 to 131072. The unit is 8 KB.
Default value: 8MB (1024 x 8 KB)
cstore_prefetch_quantity
Parameter description: Specifies the amount of I/O that the column-store prefetches using the ADIO.
This parameter is a USERSET parameter. Set it based on instructions provided in Table 1.
Value range: an integer ranging from 1024 to 1048576. The unit is KB.
Default value: 32MB
cstore_backwrite_quantity
Parameter description: Specifies the amount of I/O that the column-store writes using the ADIO.
This parameter is a USERSET parameter. Set it based on instructions provided in Table 1.
Value range: an integer ranging from 1024 to 1048576. The unit is KB.
Default value: 8MB
cstore_backwrite_max_threshold
Parameter description: Specifies the maximum amount of buffer I/O that the column-store writes in the database using the ADIO.
This parameter is a USERSET parameter. Set it based on instructions provided in Table 1.
Value range: an integer ranging from 4096 to INT_MAX/2. The unit is KB.
Default value: 2GB
fast_extend_file_size
Parameter description: Specifies the disk size that the row-store pre-scales using the ADIO.
This parameter is a SUSET parameter. Set it based on instructions provided in Table 1.
Value range: an integer ranging from 1024 to 1048576. The unit is KB.
Default value: 8MB
effective_io_concurrency
Parameter description: Specifies the number of requests that can be simultaneously processed by a disk subsystem. For the RAID array, the parameter value must be the number of disk drive spindles in the array.
This parameter is a USERSET parameter. Set it based on instructions provided in Table 1.
Value range: an integer ranging from 0 to 1000
Default value: 1