Feature Description
TDStore uses the LSM-tree structure to organize and store data. The LSM-tree organizes data in hierarchical levels, ranging from Level 0 to Level N. Newly written data is first flushed to Level 0. The LSM-tree periodically initiates compaction operations to reorganize stored data, gradually moving data from upper levels to lower levels to maintain an optimal state. During this process, expired versions of data are cleaned up to release redundant disk space, achieving optimal read and write performance. When the database experiences excessive write pressure and compaction operations cannot reorganize newly written data in time, the LSM-tree structure degrades, leading to reduced read and write performance. Upon reaching a certain threshold, TDStore automatically enters a write-throttling state (limiting the speed of write requests) or even a write-rejection state (rejecting all write requests). At this point, TDStore's write performance reaches a bottleneck.
tdstore_user_cf_level0_stop_writes_trigger is used to set the threshold for TDStore to enter the write-rejection state. When the number of data files at LSM-tree level 0 exceeds this parameter, TDStore will enter the write-rejection state and reject all write requests. By properly setting tdstore_user_cf_level0_stop_writes_trigger, you can control the threshold for entering the write-rejection state, thereby optimizing system performance and resource utilization.
Attribute Description
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Parameter Type | UINT |
Default Value | 128 |
Value Range | 1 ~ 2147483647 |
Effective Scope | GLOBAL |
Restart Required | No |