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From "Yi Deng (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HBASE-11046) New Scanner API
Date Tue, 22 Apr 2014 02:17:14 GMT

     [ https://issues.apache.org/jira/browse/HBASE-11046?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Yi Deng updated HBASE-11046:
----------------------------

    Description: 
A new scanner API for reducing unnecessary RPC calls:
Motivation:
# RPC is expensive to both client and server.
# The most important function for scanning is getting data, but for each scanning process
within a region, there are 3 times of RPC that doesn't transfer data: open, last next, and
close, I want to remove them all (for most of the situation)

Solution:
# a new scanner API (*scanOpen*) which has an option of transfer data along with the scannerID
back in this call
# a new scanner API (*scanNext*) which is similar to current next, but returns flags of whether
more data is available and whether need to scan next region. If no data left, automatically
close the scanner.
# *scanClose* is still useful when you want to close the scanner before reach the end.

For most of the meta-scan, only one RPC will fetch all lines.

  was:
A new scanner API for reducing unnecessary RPC calls:
Motivation:
# RPC is expensive to both client and server.
# The most important function for scanning is getting data, but for each scanning process
within a region, there are 3 times of RPC that doesn't transfer data: open, last next, and
close, I want to remove them all (for most of the situation)

Solution:
# a new scanner API (*scanOpen*) which has an option of transfer data along with the scannerID
back in this call
# a new scanner API (*scanNext*) which is similar to current next, but returns flags of whether
more data is available and whether need to scan next region. If no data left, automatically
close the scanner.
# *scanClose* is still useful when you want to close the scanner before reach the end.


> New Scanner API
> ---------------
>
>                 Key: HBASE-11046
>                 URL: https://issues.apache.org/jira/browse/HBASE-11046
>             Project: HBase
>          Issue Type: New Feature
>          Components: Scanners
>            Reporter: Yi Deng
>              Labels: features
>             Fix For: 0.89-fb
>
>
> A new scanner API for reducing unnecessary RPC calls:
> Motivation:
> # RPC is expensive to both client and server.
> # The most important function for scanning is getting data, but for each scanning process
within a region, there are 3 times of RPC that doesn't transfer data: open, last next, and
close, I want to remove them all (for most of the situation)
> Solution:
> # a new scanner API (*scanOpen*) which has an option of transfer data along with the
scannerID back in this call
> # a new scanner API (*scanNext*) which is similar to current next, but returns flags
of whether more data is available and whether need to scan next region. If no data left, automatically
close the scanner.
> # *scanClose* is still useful when you want to close the scanner before reach the end.
> For most of the meta-scan, only one RPC will fetch all lines.



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