[
https://issues.apache.org/jira/browse/HBASE-9751?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13793447#comment-13793447
]
Vladimir Rodionov commented on HBASE-9751:
------------------------------------------
Sorry that was optimized version:
Correct numbers: 71M and 80M respectively.
The additional optimization I have done to get up to 97.5M :
I replaced Bytes.compareTo with Bytes.equalsTo when checking for stopRow. Its
a dirty hack but we always can calculate the *real* stopRow in a scanner,
correct? If Scan operation has isolation level READ_COMMITTED we calculate
*real* stopRow when scanner is created. Checking equality is much efficient
than compare operation.
I am going to open separate JIRA for this possible improvement.
> Excessive readpoints checks in MemStoreScanner and StoreFileScanner
> --------------------------------------------------------------------
>
> Key: HBASE-9751
> URL: https://issues.apache.org/jira/browse/HBASE-9751
> Project: HBase
> Issue Type: Bug
> Affects Versions: 0.98.0, 0.94.12, 0.96.0
> Reporter: Vladimir Rodionov
> Assignee: Lars Hofhansl
> Attachments: 9751-0.94.txt, 9751-trunk.txt
>
>
> It seems that usage of skipKVsNewerThanReadpoint in StoreFileScanner can be
> greatly reduced or even eliminated all together (HFiles are immutable and no
> new KVs can be inserted after scanner instance is created). The same is true
> for MemStoreScanner which checks readpoint on every next() and seek(). Each
> readpoint check is ThreadLocal.get() and it is quite expensive.
--
This message was sent by Atlassian JIRA
(v6.1#6144)
