[jira] [Assigned] (IOTDB-3100) Semantics change of TsFile filename

["Jialin Qiao (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/IOTDB-3100?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Jialin Qiao reassigned IOTDB-3100:
----------------------------------

    Assignee: yusicheng  (was: Haiming Zhu)

> Semantics change of TsFile filename
> -----------------------------------
>
>                 Key: IOTDB-3100
>                 URL: https://issues.apache.org/jira/browse/IOTDB-3100
>             Project: Apache IoTDB
>          Issue Type: Improvement
>          Components: Core/Engine
>            Reporter: Haiming Zhu
>            Assignee: yusicheng
>            Priority: Major
>              Labels: pull-request-available
>
> Currently, the filename format of each tsfile is \{file_created_time}-\{version_id}-\{inner_space_merge_num}-\{cross_space_merge_num}.tsfile. In one time partition, the order of tsfiles is guaranteed by the version_id, for example, 1651825804093-2-0-0.tsfile is after 1651825804092-1-0-0.tsfile
>  
> The problem is that filename conflict may occur in the cross space compaction and load scenes. In the cross space compaction, assuming there exists 3-2-0-0.tsfile, 4-3-0-0.tsfile and 5-5-0-0.tsfile in the sequence folder, if file 4-3-0-0.tsfile is selected, compaction cannot generate 3 or more target files because only 2 version_id are left between 2 and 5, so some big target files may be generated. In the load, assuming there exists 3-2-0-0.tsfile, 3-3-0-0.tsfile and 3-3-0-0.tsfile in the sequence folder, no more sequence files cannot be loaded between 3-2-0-0.tsfile and 3-3-0-0.tsfile, they can only be loaded into the unsequence folder.
>  
> In response to these problems, the format won't be changed, but the meaning of file_created_time and version_id will be different. Instead of version_id, we use file_created_time to guarantee the order of tsfiles, and if two tsfiles have the same file_created_time, then we use version_id to guarantee the order. This semantics change may afftect query, compaction and load module.



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