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Posted to issues@trafodion.apache.org by "Eric Owhadi (JIRA)" <ji...@apache.org> on 2015/07/29 22:05:04 UTC
[jira] [Work started] (TRAFODION-1420) Use ClientSmallScanner for
small scans to improve performance
[ https://issues.apache.org/jira/browse/TRAFODION-1420?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Work on TRAFODION-1420 started by Eric Owhadi.
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> Use ClientSmallScanner for small scans to improve performance
> -------------------------------------------------------------
>
> Key: TRAFODION-1420
> URL: https://issues.apache.org/jira/browse/TRAFODION-1420
> Project: Apache Trafodion
> Issue Type: Improvement
> Components: sql-cmp, sql-exe
> Reporter: Eric Owhadi
> Assignee: Eric Owhadi
> Labels: performance
> Fix For: 2.0-incubating
>
>
> Hbase implements an optimization for small scan (defined as scanning less than a data block ie 64Kb) resulting in 3X performance improvement. The underlying trick is about cutting down RPC calls from 3 (OpenScan/Next/Close) to 1, and use pread stateless instead of seek/read state-full and locking method to read data. This JIRA is about improving the compiler who can be aware if a scan will be acting on single data block (small) or not, and pass this data to executor so that it can use the right parameter for scan. (scan.setSmall(boolean)).
> reference:
> https://issues.apache.org/jira/browse/HBASE-9488
> https://issues.apache.org/jira/browse/HBASE-7266
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