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From "Kristian Waagan (JIRA)" <j...@apache.org>
Subject [jira] Updated: (DERBY-3791) Excessive memory usage when fetching small Clobs
Date Fri, 01 Aug 2008 15:30:32 GMT

     [ https://issues.apache.org/jira/browse/DERBY-3791?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Kristian Waagan updated DERBY-3791:
-----------------------------------

    Attachment: derby-3791-2a-buffer-adjustments.diff

'derby-3791-2a-buffer-adjustments.diff' adjusts the buffer sizes of the internal char array
and the BufferedInputStream.
If the Clob is known to be smaller than 8 KB (maximum allowed buffer size), the buffer is
set to match the Clob size.
Note that the internal buffer is for characters, whereas the stream buffers bytes. The same
size is used for both.

Committed to trunk with revision 681723.

> Excessive memory usage when fetching small Clobs
> ------------------------------------------------
>
>                 Key: DERBY-3791
>                 URL: https://issues.apache.org/jira/browse/DERBY-3791
>             Project: Derby
>          Issue Type: Bug
>          Components: JDBC
>    Affects Versions: 10.2.2.0, 10.3.1.4, 10.4.1.3, 10.5.0.0
>            Reporter: Kristian Waagan
>            Assignee: Kristian Waagan
>            Priority: Minor
>         Attachments: derby-3791-1a-buffer_fix.diff, derby-3791-2a-buffer-adjustments.diff
>
>
> When investigating DERBY-3312 I found out that performance with the embedded driver has
decreased a lot as well.
> Analysis on trunk indicate excessive memory usage, causing high allocation and garbage
collection costs.
> I believe there was another major performance problem in 10.3, but it appears fixed in
trunk. I have not spent time identifying this problem.

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