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https://issues.apache.org/jira/browse/HBASE-22448?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16845481#comment-16845481
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Zheng Hu commented on HBASE-22448:
----------------------------------
[~KarthickRam], Thanks for your report. I created a benchmark UT for your
case, cost about 8s ~ 10s in branch-1.4 ( rev-id: 416c41e) under my local
host. Will try this test in branch-1.2.
BTW, you can also try this patch in your host by the following:
{code}
curl -s
https://issues.apache.org/jira/secure/attachment/12969351/0001-benchmark-UT.patch
| git am
wget https://issues.apache.org/jira/secure/attachment/12969259/qualifiers.txt
-O /home/openinx/Downloads/qualifiers.txt
mvn test -Dtest=TestScanBenchmark
{code}
You'll find a log say:
{code}
2019-05-22 11:41:55,817 INFO [main] regionserver.TestScanBenchmark(98): Total
time consumed: 8728 (ms). count: 1
{code}
> Scan is slow for Multiple Column prefixes
> -----------------------------------------
>
> Key: HBASE-22448
> URL: https://issues.apache.org/jira/browse/HBASE-22448
> Project: HBase
> Issue Type: Bug
> Components: Scanners
> Affects Versions: 1.4.8, 1.4.9
> Reporter: Karthick
> Assignee: Zheng Hu
> Priority: Critical
> Labels: prefix, scan, scanner
> Fix For: 1.5.0, 1.4.10
>
> Attachments: 0001-benchmark-UT.patch, HBaseFileImport.java,
> qualifiers.txt, scanquery.txt
>
>
> While scanning a row (around 10 lakhs columns) with 100 column prefixes, it
> takes around 4 seconds in hbase-1.2.5 and when the same query is executed in
> hbase-1.4.9 it takes around 50 seconds.
> Is there any way to optimise this?
>
> *P.S:*
> We have applied the patch provided in
> [-HBASE-21620-|https://jira.apache.org/jira/browse/HBASE-21620] and
> [-HBASE-21734-|https://jira.apache.org/jira/browse/HBASE-21734] . Attached
> *qualifiers*.*txt* file which contains the column keys. Use the
> *HBaseFileImport.java* file provided to populate in your table and use
> *scanquery.txt* to query.
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