[jira] [Resolved] (CARBONDATA-458) Improving carbon first time query performance

[Akash R Nilugal (Jira)]

     [ https://issues.apache.org/jira/browse/CARBONDATA-458?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Jacky Li resolved CARBONDATA-458.
---------------------------------
       Resolution: Fixed
    Fix Version/s: 0.3.0-incubating

>  Improving carbon first time query performance
> ----------------------------------------------
>
>                 Key: CARBONDATA-458
>                 URL: https://issues.apache.org/jira/browse/CARBONDATA-458
>             Project: CarbonData
>          Issue Type: Improvement
>          Components: core, data-load, data-query
>            Reporter: kumar vishal
>            Assignee: kumar vishal
>             Fix For: 0.3.0-incubating
>
>          Time Spent: 4.5h
>  Remaining Estimate: 0h
>
> Improving carbon first time query performance
> Reason:
> 1. As file system cache is cleared file reading will make it slower to read and cache
> 2. In first time query carbon will have to read the footer from file data file to form the btree
> 3. Carbon reading more footer data than its required(data chunk)
> 4. There are lots of random seek is happening in carbon as column data(data page, rle, inverted index) are not stored together.
> Solution:
> 1. Improve block loading time. This can be done by removing data chunk from blockletInfo and storing only offset and length of data chunk
> 2. compress presence meta bitset stored for null values for measure column using snappy
> 3. Store the metadata and data of a column together and read together this reduces random seek and improve IO

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