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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-402) Apache IoTDB: Metadata (Schema)
Storage Engine
[ https://issues.apache.org/jira/browse/COMDEV-402?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Xiangdong Huang closed COMDEV-402.
----------------------------------
Resolution: Duplicate
deplicate with COMDEV-403
> Apache IoTDB: Metadata (Schema) Storage Engine
> ----------------------------------------------
>
> Key: COMDEV-402
> URL: https://issues.apache.org/jira/browse/COMDEV-402
> 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 tree-based structure in memory to manage the schema (a.k.a, metadata), and use a Write-Ahead-Log-like file structure to persist the schema.
> Now, each time series will take about 300 Bytes in memory. However, an IoTDB instance may manage more than 100 million time series, which may take more than 30GB memory.
> Therefore, we'd like to re-design the schema management module.
> 1. File: Persist the tree on disk like a b-tree.
> 2. WAL: implement the WAL of the metadata. So we can update the tree on disk in batch, rather than one operation by one.
> 3. Cache: we may have no memory to load the whole tree. So a cache is needed and query from the tree on disk is needed.
> What knowledge you need to know:
> 1. Java
> 2. Basic design idea about Database [2]
> [1] https://iotdb.apache.org
> [2] http://pages.cs.wisc.edu/~dbbook/openAccess/firstEdition/slides/pdfslides/mod2l1.pdf
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