[jira] [Assigned] (IOTDB-1264) Insert unseq file to seq files when possible

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

     [ https://issues.apache.org/jira/browse/IOTDB-1264?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

WangChao reassigned IOTDB-1264:
-------------------------------

    Assignee: WangChao

> Insert unseq file to seq files when possible
> --------------------------------------------
>
>                 Key: IOTDB-1264
>                 URL: https://issues.apache.org/jira/browse/IOTDB-1264
>             Project: Apache IoTDB
>          Issue Type: Improvement
>          Components: Core/Engine
>            Reporter: Tian Jiang
>            Assignee: WangChao
>            Priority: Minor
>              Labels: file, unseq
>
> We judge if data belongs to the seq region or unseq region only by the lastFlushedTime of each device, which makes the following situation possible:
> 2 seq files and their time ranges: seq1[0, 99], seq2[300, 500]
> 1 unseq file and its time range: unseq1[150, 200]
> Intuitively, we can just make them 3 seq files, which may potentially reduce query overhead.
> One solution may be: right after we close one unseq file, we check if it actually overlaps with any seq file(s), and if not, we insert it into a proper position of the seq files instead of keeping it in unseq files. Another merit is that this avoids the case mentioned in https://github.com/apache/iotdb/pull/2920#pullrequestreview-623932806, because each unseq file will definitely overlap at least one seq file.



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