default_progressive_merge_num specifies the default number of progressive compactions when a table is created.
| Attribute | Description |
|---|---|
| Type | Integer |
| Default value | 0 |
| Value range | [0, +∞) |
| Effective upon restart of OBServer node | No |
OceanBase Database supports progressive compactions on table data. After performing a DDL operation that needs to rewrite the data, OceanBase Database can distribute data rewriting to multiple compaction operations. During each compaction, only some of the data is rewritten. You can use the table-level attribute progressive_merge_num to control the compaction, or use the default_progressive_merge_num parameter to set the default number of progressive compactions when a table is created.
If you do not specify the progressive_merge_num attribute when you create a table, OceanBase Database will set the value of this attribute to the value of default_progressive_merge_num.
The values of the progressive_merge_num attribute are described as follows:
- 0: indicates that the default value 100 is used.
- 1: indicates that a full compaction is force performed and that no progressive compaction is performed.
- X: indicates that the data will be rewritten in X rounds of compactions. 1/X of the data is rewritten in each round of compaction.