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Posted to dev@community.apache.org by "Xiangdong Huang (Jira)" <ji...@apache.org> on 2021/03/12 11:46:00 UTC
[jira] [Closed] (COMDEV-401) Apache IoTDB: Metadata (Schema)
Storage Engine
[ https://issues.apache.org/jira/browse/COMDEV-401?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Xiangdong Huang closed COMDEV-401.
----------------------------------
Resolution: Duplicate
deplicate with COMDEV-403
> Apache IoTDB: Metadata (Schema) Storage Engine
> ----------------------------------------------
>
> Key: COMDEV-401
> URL: https://issues.apache.org/jira/browse/COMDEV-401
> Project: Community Development
> Issue Type: Task
> Components: GSoC/Mentoring ideas
> Reporter: Xiangdong Huang
> Priority: Major
> Labels: IoTDB
>
> Apache IoTDB [1] is an Open Source IoT database designed to meet the rigorous data, storage, and analytics requirements of large-scale Internet of Things (IoT) and Industrial Internet of Things (IIoT) applications.
> Different with traditional relational databases, IoTDB uses a tree-based structure to store its schema (a.k.a, metadata) in memory, and only persists the structure on disk in a write ahead log form.
> In memory, the memory cost of each time series wil take about 300 bytes.
> However, when the tree is too large (e.g., there are 100 million time series), IoTDB will take too much memory.
> Therefore, we'd like to develop a metadata storage engine module. The engine will do the following tasks:
> 1. data file: Persist the tree on disk, like a b-tree structure. (need to support CRUD)
> 2. WAL: to accelerate the IO operation, we can save schema modification operations as Write Ahead Log, and then write back to the tree file in an atomic way.
> 3. Cache: If there is no much memory, just load a part of the tree into memory.
> What you need:
> 1. Java language
> 2. Know some basic design idea of database data file, e.g., slot file.[2]
> [1] https://iotdb.apache.org
> [2] http://pages.cs.wisc.edu/~dbbook/openAccess/firstEdition/slides/pdfslides/mod2l1.pdf
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