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| |
| # 数据分区 |
| |
| 时间序列数据在存储组和时间范围两个层级上进行分区 |
| |
| ## 存储组 |
| |
| 存储组由用户显示指定，使用语句"SET STORAGE GROUP TO"来指定存储组，每一个存储组有一个对应的 StorageGroupProcessor |
| |
| 其拥有的主要字段为： |
| |
| * 一个读写锁: insertLock |
| |
| * 每个时间分区所对应的未关闭的顺序文件处理器: workSequenceTsFileProcessors |
| |
| * 每个时间分区所对应的未关闭的乱序文件处理器: workUnsequenceTsFileProcessors |
| |
| * 该存储组的全部顺序文件列表（按照时间排序）: sequenceFileTreeSet |
| |
| * 该存储组的全部乱序文件列表（无顺序）: unSequenceFileList |
| |
| * 记录每一个设备最后写入时间的map，顺序数据刷盘时会使用该map记录的时间: latestTimeForEachDevice |
| |
| * 记录每一个设备最后刷盘时间的map，用来区分顺序和乱序数据: latestFlushedTimeForEachDevice |
| |
| * 每个时间分区所对应的版本生成器map，便于查询时确定不同chunk的优先级: timePartitionIdVersionControllerMap |
| |
| |
| ### 相关代码 |
| |
| * src/main/java/org/apache/iotdb/db/engine/StorageEngine.java |
| |
| |
| ## 时间范围 |
| |
| 同一个存储组中的数据按照用户指定的时间范围进行分区，相关参数为partition_interval，默认为周，也就是不同周的数据会放在不同的分区中 |
| |
| ### 实现逻辑 |
| |
| StorageGroupProcessor 对插入的数据进行分区计算，找到指定的 TsFileProcessor，而每一个 TsFileProcessor 对应的 TsFile 会被放置在不同的分区文件夹内 |
| |
| ### 文件结构 |
| |
| 分区后的文件结构如下： |
| |
| data |
| |
| -- sequence |
| |
| ---- [存储组名1] |
| |
| ------ [时间分区ID1] |
| |
| -------- xxxx.tsfile |
| |
| -------- xxxx.resource |
| |
| ------ [时间分区ID2] |
| |
| ---- [存储组名2] |
| |
| -- unsequence |
| |
| ### 相关代码 |
| |
| * src/main/java/org/apache/iotdb/db/engine/storagegroup.StoragetGroupProcessor.java 中的 getOrCreateTsFileProcessorIntern 方法 |
