Parameter |
Description |
Recommended value/range |
|---|---|---|
| syslog_io_bandwidth_limit | The maximum process log printing bandwidth. | Recommended value: 10 MB. The default value is 30 MB. |
| syslog_level | The system log level. | PERF for performance scenarios. |
| clog_sync_time_warn_threshold | The threshold of log synchronization time for reporting an alert in the log. | We recommend that you set it to a larger value. However, note that a large value may affect the investigation into slow clog synchronization issues. |
| trace_log_slow_query_watermark | The threshold of transaction execution time for the generation of slow trans logs. | We recommend that you set this parameter to a large value to avoid the generation of trace logs for slow queries. |
| max_syslog_file_count | The maximum allowed number of observers.log files. The log files are automatically recycled when the specified number is reached. | We recommend that you adjust the value based on the disk space. |
| enable_sql_operator_dump | Specifies whether to allow SQL layer operations such as hash join to dump intermediate results. Enabling this feature helps avoid memory overflow errors. | We recommend that you enable it for AP testing. |
| _temporary_file_io_area_size | The total size of intermediate SQL (such as hash join) results at the storage layer. | We recommend that you set it to a larger value for AP testing. |
| builtin_db_data_verify_cycle | The macroblock inspection cycle. Inspection is disabled if the value is set to 0. | We recommend that you set this parameter to 0 for performance scenarios. |
| disk_io_thread_count | The number of disk I/O threads. The value must be an even number. | You may adjust the value based on the I/O load. |
| enable_async_syslog | Specifies whether to enable asynchronous logs. | We recommend that you set the value to True for performance scenarios. |
| fuse_row_cache_priority | The priority of the fuse row cache in the KV cache. OceanBase Database features a multi-level storage architecture. For a query of a row with multiple columns in the MemStore, mini SSTable, minor SSTable, and SSTable, OceanBase Database needs to fuse these columns. In this case, the fuse row cache is used to cache the row, so that OceanBase Database no longer needs to fuse the row for subsequent queries. The cache has some effect on performance. | We recommend that you set it to a value greater than 1 to avoid premature replacement of this cache. |
| micro_block_merge_verify_level | The macroblock verification level. The value 0 indicates no verification. | In performance scenarios, you can set it to 0. However, we do not recommend that you change the default value in a production system. |
| compaction_low_thread_score | The number of concurrent threads for low-priority compactions. Low-priority compactions are initiated for major SSTables. | The default value is 0, which indicates six concurrent threads. To increase the number of concurrent threads, you can increase the value of this parameter. |
| compaction_mid_thread_score | The number of concurrent threads for medium-priority compactions. Medium-priority compactions are initiated for minor SSTables. | The default value is 0, which indicates six concurrent threads. To increase the number of concurrent threads, you can increase the value of this parameter. |
| compaction_high_thread_score | The number of concurrent threads for high-priority compactions. High-priority compactions are initiated for mini SSTables. | The default value is 0, which indicates six concurrent threads. To increase the number of concurrent threads, you can increase the value of this parameter. |
I/O parameters
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