[
https://issues.apache.org/jira/browse/HBASE-5001?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13167358#comment-13167358
]
Lars Hofhansl commented on HBASE-5001:
--------------------------------------
Was thinking something as simple as this:
{code}
public class Key {
private String file;
private long offset;
public Key(String file, long offset) {
this.file = file;
this.offset = offset;
}
@Override
public int hashCode() {
return file.hashCode()*127+(int)(offset ^ (offset >>> 32));
}
@Override
public boolean equals(Object o) {
if (o instanceof Key) {
Key k = (Key)o;
return offset == k.offset && (file == null ? k.file == null :
file.equals(k.file));
} else {
return false;
}
}
}
{code}
> Improve the performance of block cache keys
> -------------------------------------------
>
> Key: HBASE-5001
> URL: https://issues.apache.org/jira/browse/HBASE-5001
> Project: HBase
> Issue Type: Improvement
> Affects Versions: 0.90.4
> Reporter: Jean-Daniel Cryans
> Priority: Minor
> Fix For: 0.94.0
>
>
> Doing a pure random read test on data that's 100% block cache, I see that we
> are spending quite some time in getBlockCacheKey:
> {quote}
> "IPC Server handler 19 on 62023" daemon prio=10 tid=0x00007fe0501ff800
> nid=0x6c87 runnable [0x00007fe0577f6000]
> java.lang.Thread.State: RUNNABLE
> at java.util.Arrays.copyOf(Arrays.java:2882)
> at
> java.lang.AbstractStringBuilder.expandCapacity(AbstractStringBuilder.java:100)
> at
> java.lang.AbstractStringBuilder.append(AbstractStringBuilder.java:390)
> at java.lang.StringBuilder.append(StringBuilder.java:119)
> at
> org.apache.hadoop.hbase.io.hfile.HFile.getBlockCacheKey(HFile.java:457)
> at
> org.apache.hadoop.hbase.io.hfile.HFileReaderV2.readBlock(HFileReaderV2.java:249)
> at
> org.apache.hadoop.hbase.io.hfile.HFileBlockIndex$BlockIndexReader.seekToDataBlock(HFileBlockIndex.java:209)
> at
> org.apache.hadoop.hbase.io.hfile.HFileReaderV2$ScannerV2.seekTo(HFileReaderV2.java:521)
> at
> org.apache.hadoop.hbase.io.hfile.HFileReaderV2$ScannerV2.seekTo(HFileReaderV2.java:536)
> at
> org.apache.hadoop.hbase.regionserver.StoreFileScanner.seekAtOrAfter(StoreFileScanner.java:178)
> at
> org.apache.hadoop.hbase.regionserver.StoreFileScanner.seek(StoreFileScanner.java:111)
> at
> org.apache.hadoop.hbase.regionserver.StoreFileScanner.seekExactly(StoreFileScanner.java:219)
> at
> org.apache.hadoop.hbase.regionserver.StoreScanner.<init>(StoreScanner.java:80)
> at
> org.apache.hadoop.hbase.regionserver.Store.getScanner(Store.java:1689)
> at
> org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl.<init>(HRegion.java:2857)
> {quote}
> Since the HFile name size is known and the offset is a long, it should be
> possible to allocate exactly what we need. Maybe use byte[] as the key and
> drop the separator too.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:
https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira
