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Posted to issues@hbase.apache.org by "jiraposter@reviews.apache.org (Commented) (JIRA)" <ji...@apache.org> on 2011/09/28 18:04:46 UTC
[jira] [Commented] (HBASE-2794) ROWCOL bloom filter not used if
multiple columns within same family are requested in a Get
[ https://issues.apache.org/jira/browse/HBASE-2794?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13116569#comment-13116569 ]
jiraposter@reviews.apache.org commented on HBASE-2794:
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This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/2084/
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Review request for hbase.
Summary
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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.
This addresses bug HBASE-2794.
https://issues.apache.org/jira/browse/HBASE-2794
Diffs
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src/main/java/org/apache/hadoop/hbase/regionserver/StoreFileScanner.java 08d3ba4
src/main/java/org/apache/hadoop/hbase/regionserver/StoreScanner.java ac2348e
src/main/java/org/apache/hadoop/hbase/regionserver/MemStore.java 4aa72de
src/main/java/org/apache/hadoop/hbase/regionserver/ScanQueryMatcher.java 68cdac5
src/main/java/org/apache/hadoop/hbase/regionserver/StoreFile.java fd9e7ef
src/main/java/org/apache/hadoop/hbase/regionserver/KeyValueHeap.java 9d9895c
src/main/java/org/apache/hadoop/hbase/regionserver/KeyValueScanner.java 6cdada7
src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java 7cbdb98
src/main/java/org/apache/hadoop/hbase/regionserver/AbstractKeyValueScanner.java PRE-CREATION
src/main/java/org/apache/hadoop/hbase/KeyValue.java 585c4a8
src/main/java/org/apache/hadoop/hbase/io/hfile/AbstractHFileReader.java f5173c4
src/main/java/org/apache/hadoop/hbase/io/hfile/HFile.java a3d778e
src/main/java/org/apache/hadoop/hbase/util/CollectionBackedScanner.java 32f88fb
src/test/java/org/apache/hadoop/hbase/regionserver/TestKeyValueHeap.java a5d13f7
src/test/java/org/apache/hadoop/hbase/regionserver/TestMultiColumnScanner.java baee696
src/test/java/org/apache/hadoop/hbase/regionserver/TestScanWithBloomError.java PRE-CREATION
Diff: https://reviews.apache.org/r/2084/diff
Testing
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Existing unit tests. A new unit test (TestScanWithBloomError). Load testing using HBaseTest.
Thanks,
Mikhail
> 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
>
> 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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