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Posted to issues@trafodion.apache.org by "Eric Owhadi (JIRA)" <ji...@apache.org> on 2015/07/24 21:13:04 UTC

[jira] [Created] (TRAFODION-1420) Use ClientSmallScanner for small scans to improve performance

Eric Owhadi created TRAFODION-1420:
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             Summary: 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
             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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