[
https://issues.apache.org/jira/browse/HBASE-1347?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12703759#action_12703759
]
atppp commented on HBASE-1347:
------------------------------
All ran faster in my old test, however, that was not a good test.
I did a better test today: run just
byte[] HRegion.binaryIncrement(byte[], long amount)
100M times (converting long to and from byte[] is done outside the loop, so
improvement in Bytes class won't affect old algorithm's performance.). Here's
result:
current code on 0.19 branch: (time per run)
amount=+1: 10.9 ns
amount=+1000: 23.3 ns
amount=-1: 98.7 ns (result incorrect)
amount=random Long: ~100 ns (result is incorrect when amount<0)
Performance of my quick fix is pretty consistent (obviously):
with 0.19 branch Bytes class: ~73 ns
with trunk branch Bytes class: ~53 ns
I imagine most people do amount=+1, so the difference is huge. I don't want to
propose my quick fix code as a "good" solution, but I am uploading that patch
anyway for reference.
> HTable.incrementColumnValue does not take negative 'amount'
> -----------------------------------------------------------
>
> Key: HBASE-1347
> URL: https://issues.apache.org/jira/browse/HBASE-1347
> Project: Hadoop HBase
> Issue Type: Improvement
> Components: client
> Affects Versions: 0.19.1
> Environment: Ubuntu 8.10
> Reporter: atppp
> Priority: Minor
> Fix For: 0.19.2
>
>
> Apparently HRegion.binaryIncrement() assumes argument 'amount' is always
> positive. It would be nice to support decrement operation. In my application,
> a counter can go both up and down.
> Quick fix is
> public byte [] binaryIncrement(byte [] value, long amount) {
> return Bytes.toBytes(Bytes.toLong(value) + amount);
> }
> but it is 2x~3x slower than current implementation for small positive
> 'amount' value. I have not yet found a good implementation to support
> negative 'amount' argument, AND match the speed of current implementation.
> Anyway, I just want to throw this out there and see if anybody is interested
> in negative 'amount' support.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
