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https://issues.apache.org/jira/browse/IOTDB-5093?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17642504#comment-17642504
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周沛辰 commented on IOTDB-5093:
----------------------------
*跨空间选文件流程：* #
从TsFileManager里获取seqFiles和unseqFiles
#
过滤掉被删除的顺序文件和被删除、isCompacting、isCandidate的乱序文件，放入CandidateList
#
从CandidateList里选择有重叠的顺乱序文件，每选一个乱序文件，就检查其顺序文件是否有效（若isCompacting、isCandidate、isDeleted则无效），若否则返回
*Bug产生：*
!image-2022-12-02-21-29-16-925.png|width=853,height=205!
文件3 4正在被其他线程合并，接着来了跨空间选文件，选文件流程： #
获取的seqFiles里有1 2 3 4 5。（接着其他合并线程对文件3'与3 4进行内存置换，然后 3 4 被置为deleted并删除了）
#
第二步的时候就会过滤掉 3 4，将 1 2 5放入CandidateList里
#
从CandidateList里进行选文件，选中1 2 5 6，导致合出来的目标文件与其他文件有重叠
*解决方法：* #
获取 1 2 3 4 5
#
不对顺序文件进行过滤，因此顺序CandidateList里有1 2 3 4 5
#
选文件发现3 4 正在被其他合并占用或者被删除 丢弃文件
> Fix compaction selector bug
> ---------------------------
>
> Key: IOTDB-5093
> URL: https://issues.apache.org/jira/browse/IOTDB-5093
> Project: Apache IoTDB
> Issue Type: Bug
> Affects Versions: master branch, 0.13.0-SNAPSHOT
> Reporter: 周沛辰
> Assignee: 周沛辰
> Priority: Major
> Labels: pull-request-available
> Fix For: 1.0.0
>
> Attachments: image-2022-12-02-21-29-16-925.png
>
>
> *Description*
> target file overlap with previous file
>
> *Reason*
> In the process of getting the file list and starting to select files, the
> file list is updated (the file is deleted or the status is updated). When a
> seq file is occupied and deleted by other compaction thread, and it happens
> to select files in cross space compaction, the deleted file will be filtered
> out, resulting in an overlap target file.
>
> *Solution*
> Do not filter out any seq files before selecting the files. After selecting
> the files, judge whether the seq files have been deleted or being compacted.
> If there are any, the task will be discarded.
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