Disk Space

sql_use_spacelimit

Parameter description: Specifies the space size for files to be flushed to disks when a single SQL statement is executed on a single DN. The managed space includes the space occupied by ordinary tables, temporary tables, and intermediate result sets to be flushed to disks.

Type: USERSET

Value range: an integer ranging from -1 to INT_MAX. The unit is KB. –1 indicates no limit.

Default value: –1

bi_page_reuse_factor

Parameter description: Specifies the percentage of idle space of old pages that can be reused when page replication is used for data synchronization between primary and standby DNs in the scenario where data is inserted into row-store tables in batches.

Type: USERSET

Value range: an integer ranging from 0 to 100. The value is a percentage. Value 0 indicates that the old pages are not reused and new pages are requested.

Default value: 70

• In an upgrade, the default value of this parameter is the same as that in the cluster before the upgrade. In a newly installed 8.1.1.500 cluster, the default value of this parameter is 0.
• You are not advised to set this parameter to a value less than 50 (except 0). If the idle space of the reused page is small, too much old page data will be transmitted between the primary and standby DNs. As a result, the batch insertion performance deteriorates.
• You are not advised to set this parameter to a value greater than 90. If this parameter is set to a value greater than 90, idle pages will be frequently queried, but old pages cannot be reused.

temp_file_limit

Parameter description: Specifies the size of a single file spilled to disk if splitting is triggered in a session. The temporary file can be the one used by sorting or hash tables, or cursors in a session.

This is a session-level setting.

Type: SUSET

Value range: an integer ranging from -1 to INT_MAX. The unit is KB. –1 indicates no limit.

Default value: –1

This parameter does not apply to disk space occupied by temporary tablespaces used for executing SQL queries.