hadoop-common-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Mingliang Liu (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HADOOP-14478) Optimize NativeAzureFsInputStream for positional reads
Date Fri, 02 Jun 2017 23:53:04 GMT

     [ https://issues.apache.org/jira/browse/HADOOP-14478?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel

Mingliang Liu updated HADOOP-14478:
    Status: Patch Available  (was: Open)

> Optimize NativeAzureFsInputStream for positional reads
> ------------------------------------------------------
>                 Key: HADOOP-14478
>                 URL: https://issues.apache.org/jira/browse/HADOOP-14478
>             Project: Hadoop Common
>          Issue Type: Bug
>          Components: fs/azure
>            Reporter: Rajesh Balamohan
>            Assignee: Rajesh Balamohan
>         Attachments: HADOOP-14478.001.patch, HADOOP-14478.002.patch
> Azure's {{BlobbInputStream}} internally buffers 4 MB of data irrespective of the data
length requested for. This would be beneficial for sequential reads. However, for positional
reads (seek to specific location, read x number of bytes, seek back to original location)
this may not be beneficial and might even download lot more data which are not used later.
> It would be good to override {{readFully(long position, byte[] buffer, int offset, int
length)}} for {{NativeAzureFsInputStream}} and make use of {{mark(readLimit)}} as a hint to
Azure's BlobInputStream.
> BlobInputStream reference: https://github.com/Azure/azure-storage-java/blob/master/microsoft-azure-storage/src/com/microsoft/azure/storage/blob/BlobInputStream.java#L448
> BlobInputStream can consider this as a hint later to determine the amount of data to
be read ahead. Changes to BlobInputStream would not be addressed in this JIRA.

This message was sent by Atlassian JIRA

To unsubscribe, e-mail: common-issues-unsubscribe@hadoop.apache.org
For additional commands, e-mail: common-issues-help@hadoop.apache.org

View raw message