• CONFIG 语法
    • gflags 参数
      • 显示变量
      • 获取变量
      • 更新变量

    CONFIG 语法

    Nebula Graph 使用 gflags 进行运行时配置。

    gflags 参数

    相关的 gflags 参数有四个，其中，max_edge_returned_per_vertex 用来控制一个点最多可以搜索返回的边数，rocksdb_db_options，rocksdb_column_family_options，rocksdb_block_based_table_options 三个参数均为 json 格式，其中每个参数 key 和 value 均为 string 格式。例如可以在 storage 的 conf 文件中做如下设置：

    1.     rocksdb_db_options = {"stats_dump_period_sec":"200", "enable_write_thread_adaptive_yield":"false", "write_thread_max_yield_usec":"600",
    2.     "max_edge_returned_per_vertex":"INT_MAX"}
    3.     rocksdb_column_family_options = {"max_write_buffer_number":"4", "min_write_buffer_number_to_merge":"2", "max_write_buffer_number_to_maintain":"1"}
    4.     rocksdb_block_based_table_options = {"block_restart_interval":"2"}

    另外目前支持动态修改 storage service 的部分 rocksdb 参数, 如下

    1.     // rocksdb_column_family_options
    2.     max_write_buffer_number
    3.     level0_file_num_compaction_trigger
    4.     level0_slowdown_writes_trigger
    5.     level0_stop_writes_trigger
    6.     target_file_size_base
    7.     target_file_size_multiplier
    8.     max_bytes_for_level_base
    9.     max_bytes_for_level_multiplier
    10.     ttl
    11.     disable_auto_compactions
    13.     // rocksdb_db_options
    14.     max_total_wal_size
    15.     delete_obsolete_files_period_micros
    16.     max_background_jobs
    17.     base_background_compactions
    18.     max_background_compactions
    19.     stats_dump_period_sec
    20.     compaction_readahead_size
    21.     writable_file_max_buffer_size
    22.     bytes_per_sync
    23.     wal_bytes_per_sync
    24.     delayed_write_rate
    25.     avoid_flush_during_shutdown
    26.     max_open_files

    示例

    1. nebula> UPDATE CONFIGS storage:rocksdb_column_family_options = \
    2.         { disable_auto_compactions = false ,         level0_file_num_compaction_trigger = 10 }

    显示变量

    1. SHOW CONFIGS [graph|meta|storage]

    例如

    1. nebula> SHOW CONFIGS meta
    2. ============================================================================================================================
    3. | module | name                                        | type   | mode      | value                                        |
    4. ============================================================================================================================
    5. | META   | v                                           | INT64  | IMMUTABLE | 4                                            |
    6. ----------------------------------------------------------------------------------------------------------------------------
    7. | META   | help                                        | BOOL   | IMMUTABLE | False                                        |
    8. ----------------------------------------------------------------------------------------------------------------------------
    9. | META   | port                                        | INT64  | IMMUTABLE | 45500                                        |
    10. ----------------------------------------------------------------------------------------------------------------------------

    获取变量

    1. GET CONFIGS [graph|meta|storage :] var

    例如

    1. nebula> GET CONFIGS storage:load_data_interval_secs
    2. =================================================================
    3. | module  | name                      | type  | mode    | value |
    4. =================================================================
    5. | STORAGE | load_data_interval_secs   | INT64 | MUTABLE | 120   |
    6. -----------------------------------------------------------------
    1. nebula> GET CONFIGS load_data_interval_secs
    2. =================================================================
    3. | module  | name                    | type  | mode      | value |
    4. =================================================================
    5. | GRAPH   | load_data_interval_secs | INT64 | MUTABLE   | 120   |
    6. -----------------------------------------------------------------
    7. | META    | load_data_interval_secs | INT64 | IMMUTABLE | 120   |
    8. -----------------------------------------------------------------
    9. | STORAGE | load_data_interval_secs | INT64 | MUTABLE   | 120   |
    10. -----------------------------------------------------------------
    11. Got 3 rows (Time spent: 1449/2339 us)

    更新变量

    1. UPDATE CONFIGS [graph|meta|storage :] var = value

    更新的变量将永久存储于 meta-service 中。 如果变量模式为 MUTABLE，更改会即时生效。如果模式为 REBOOT，更改在服务器重启后生效。 支持在 UPDATE CONFIGS 中使用算式。

    例如

    1. nebula> UPDATE CONFIGS storage:load_data_interval_secs=1
    2. Execution succeeded (Time spent: 1750/2484 us)
    3. nebula> GET CONFIGS storage:load_data_interval_secs
    4. ===============================================================
    5. | module  | name                    | type  | mode    | value |
    6. ===============================================================
    7. | STORAGE | load_data_interval_secs | INT64 | MUTABLE | 1     |
    8. ---------------------------------------------------------------
    9. Got 1 rows (Time spent: 1678/3420 us)