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Date: Thu, 29 Sep 2011 18:42:46 +0000 (UTC)
From: "jiraposter@reviews.apache.org (Commented) (JIRA)" <jira@apache.org>
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Subject: [jira] [Commented] (HBASE-2794) ROWCOL bloom filter not used if
 multiple columns within same family are requested in a Get
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    [ https://issues.apache.org/jira/browse/HBASE-2794?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13117524#comment-13117524 ] 

jiraposter@reviews.apache.org commented on HBASE-2794:
------------------------------------------------------


bq.  On 2011-09-28 17:42:46, Ted Yu wrote:
bq.  > This is an important feature.
bq.  > 
bq.  > Since the boolean parameter, forward, correlates so closely with reseek, can we give it a better name ?
bq.  > I was thinking about either reseek or forwardOnly.
bq.  
bq.  Mikhail Bautin wrote:
bq.      We have a few diffs in the pipeline that depend on this one. Can we rename the boolean flag after we commit those diffs?

I am fine with the current name of forward.


- Ted


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On 2011-09-28 16:03:52, Mikhail Bautin wrote:
bq.  
bq.  -----------------------------------------------------------
bq.  This is an automatically generated e-mail. To reply, visit:
bq.  https://reviews.apache.org/r/2084/
bq.  -----------------------------------------------------------
bq.  
bq.  (Updated 2011-09-28 16:03:52)
bq.  
bq.  
bq.  Review request for hbase.
bq.  
bq.  
bq.  Summary
bq.  -------
bq.  
bq.  Previously we only used row-column Bloom filters for scans that only requested one column. We have seen production queries that request up to 200 columns, and with say ~6 store files per store (region / column family combination) this might have resulted in 1200 block read operations in the worst case. With this diff we will be avoiding seeks on store files that we know don't contain the row/column of interest when using an ExplicitColumnTracker. The performance should remain the same for column range queries.
bq.  
bq.  
bq.  This addresses bug HBASE-2794.
bq.      https://issues.apache.org/jira/browse/HBASE-2794
bq.  
bq.  
bq.  Diffs
bq.  -----
bq.  
bq.    src/main/java/org/apache/hadoop/hbase/regionserver/StoreFileScanner.java 08d3ba4 
bq.    src/main/java/org/apache/hadoop/hbase/regionserver/StoreScanner.java ac2348e 
bq.    src/main/java/org/apache/hadoop/hbase/regionserver/MemStore.java 4aa72de 
bq.    src/main/java/org/apache/hadoop/hbase/regionserver/ScanQueryMatcher.java 68cdac5 
bq.    src/main/java/org/apache/hadoop/hbase/regionserver/StoreFile.java fd9e7ef 
bq.    src/main/java/org/apache/hadoop/hbase/regionserver/KeyValueHeap.java 9d9895c 
bq.    src/main/java/org/apache/hadoop/hbase/regionserver/KeyValueScanner.java 6cdada7 
bq.    src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java 7cbdb98 
bq.    src/main/java/org/apache/hadoop/hbase/regionserver/AbstractKeyValueScanner.java PRE-CREATION 
bq.    src/main/java/org/apache/hadoop/hbase/KeyValue.java 585c4a8 
bq.    src/main/java/org/apache/hadoop/hbase/io/hfile/AbstractHFileReader.java f5173c4 
bq.    src/main/java/org/apache/hadoop/hbase/io/hfile/HFile.java a3d778e 
bq.    src/main/java/org/apache/hadoop/hbase/util/CollectionBackedScanner.java 32f88fb 
bq.    src/test/java/org/apache/hadoop/hbase/regionserver/TestKeyValueHeap.java a5d13f7 
bq.    src/test/java/org/apache/hadoop/hbase/regionserver/TestMultiColumnScanner.java baee696 
bq.    src/test/java/org/apache/hadoop/hbase/regionserver/TestScanWithBloomError.java PRE-CREATION 
bq.  
bq.  Diff: https://reviews.apache.org/r/2084/diff
bq.  
bq.  
bq.  Testing
bq.  -------
bq.  
bq.  Existing unit tests. A new unit test (TestScanWithBloomError). Load testing using HBaseTest.
bq.  
bq.  
bq.  Thanks,
bq.  
bq.  Mikhail
bq.  
bq.


> ROWCOL bloom filter not used if multiple columns within same family are requested in a Get
> ------------------------------------------------------------------------------------------
>
>                 Key: HBASE-2794
>                 URL: https://issues.apache.org/jira/browse/HBASE-2794
>             Project: HBase
>          Issue Type: Improvement
>          Components: performance
>            Reporter: Kannan Muthukkaruppan
>             Fix For: 0.92.0
>
>
> Noticed the following snippet in StoreFile.java:Scanner:shouldSeek():
> {code}
>         switch(bloomFilterType) {
>           case ROW:
>             key = row;
>             break;
>           case ROWCOL:
>             if (columns.size() == 1) {
>               byte[] col = columns.first();
>               key = Bytes.add(row, col);
>               break;
>             }
>             //$FALL-THROUGH$
>           default:
>             return true;
>         }
> {code}
> If columns.size > 1, then we currently don't take advantage of the bloom filter.  We should optimize this to check bloom for each of columns and if none of the columns are present in the bloom avoid opening the file.

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