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[jdbc] added LIMIT to JDBC scan operation #468

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merged 2 commits into from Nov 3, 2015

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kruthar
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@kruthar kruthar commented Nov 2, 2015

Now properly enforcing a scan of the given number of documents in the
scan operation using the LIMIT modifier in the cached statement.

Fixes #171.

Now properly enforcing a scan of the given number of documents in the
scan operation using the LIMIT modifier in the cached statement.

Fixes brianfrankcooper#171.
@cmccoy
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cmccoy commented Nov 2, 2015

I think to fulfill the intent of the scan operation there should be some ordering. Workload E (which uses scans) describes:

Application example: threaded conversations, where each scan is for the posts in a given thread (assumed to be clustered by thread id)

Allowing the DB to return, say, any record from the latter half of the database doesn't seem to match that intent.

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cmccoy commented Nov 2, 2015

Also, from the original YCSB paper:

Scan records in order, starting at a randomly chosen record key. The number of records to scan is randomly chosen.

This will ensure record ordering my the primary key.
@kruthar
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kruthar commented Nov 2, 2015

OK, added an ORDER BY clause to ensure record ordering by the primary key.

@allanbank
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Looks good to me.

@cmccoy - Any other concerns.

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cmccoy commented Nov 3, 2015

Looks good. Thanks!

cmccoy added a commit that referenced this pull request Nov 3, 2015
[jdbc] added LIMIT to JDBC scan operation
@cmccoy cmccoy merged commit 65bedc0 into brianfrankcooper:master Nov 3, 2015
@kruthar kruthar deleted the jdbc-scan-fix branch November 3, 2015 22:20
jaricftw pushed a commit to jaricftw/YCSB that referenced this pull request Jul 19, 2016
[jdbc] added LIMIT to JDBC scan operation
jaricftw pushed a commit to jaricftw/YCSB that referenced this pull request Jul 19, 2016
[jdbc] added LIMIT to JDBC scan operation
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3 participants