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From "Knut Anders Hatlen (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (DERBY-5210) Use java.nio.ByteBuffer in client.net.Request
Date Tue, 03 May 2011 14:40:03 GMT

    [ https://issues.apache.org/jira/browse/DERBY-5210?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13028249#comment-13028249
] 

Knut Anders Hatlen commented on DERBY-5210:
-------------------------------------------

I ran the sr_select performance test client with 10 threads to see if the patch affected the
performance of client/server communication (tested derbyclient.jar from 10.8.1.2 against trunk
patched with the 1a patch). Taking the average of 100 runs with each version, I could not
see any difference at all in the throughput with this kind of load. The number of CPU cycles
per transaction spent in the client driver seems to have increased by 1% because of the patch.
I hope, though, when we add the improvements suggested in DERBY-5068, that we will end up
reducing the number of CPU cycles spent in the client driver. I'll do some experimenting with
the suggested DERBY-5068 changes in combination with this patch before I go ahead with committing
it.

> Use java.nio.ByteBuffer in client.net.Request
> ---------------------------------------------
>
>                 Key: DERBY-5210
>                 URL: https://issues.apache.org/jira/browse/DERBY-5210
>             Project: Derby
>          Issue Type: Improvement
>          Components: Network Client
>    Affects Versions: 10.9.0.0
>            Reporter: Knut Anders Hatlen
>            Assignee: Knut Anders Hatlen
>         Attachments: d5210-1a.diff
>
>
> We should see if we could use a java.nio.ByteBuffer instead of a byte array in org.apache.derby.client.net.Request,
similar to what we did for DDMWriter in DERBY-2936. ByteBuffer provides some helper methods
that allows us to simplify the code that puts multi-byte values into the buffer (like ByteBuffer.putShort(),
putInt(), putLong()). It may also be a first step on the way to using a CharsetEncoder to
encode strings without going via an intermediate throw-away byte array (see DERBY-5068 for
details).

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