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From "Myrna van Lunteren (JIRA)" <j...@apache.org>
Subject [jira] Closed: (DERBY-684) Improve performance of Clob objects (ClobOutputStream#write,ClobWriter#write) on the client
Date Wed, 19 Nov 2008 17:15:44 GMT

     [ https://issues.apache.org/jira/browse/DERBY-684?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Myrna van Lunteren closed DERBY-684.
------------------------------------

    Resolution: Won't Fix

This code is now in an 'else' code path, with the if being the loblocator code, which does
create relevant objects on demand. So, this code is only used when interfacing with older
servers and it seems not cost-effective to change this anymore.

> Improve performance of Clob objects (ClobOutputStream#write,ClobWriter#write) on the
client
> -------------------------------------------------------------------------------------------
>
>                 Key: DERBY-684
>                 URL: https://issues.apache.org/jira/browse/DERBY-684
>             Project: Derby
>          Issue Type: Improvement
>          Components: Network Client, Newcomer, Performance
>    Affects Versions: 10.1.1.0, 10.1.2.1, 10.2.1.6
>         Environment: all
>            Reporter: Sunitha Kambhampati
>
> Dan suggested this improvement  here:
> http://issues.apache.org/jira/browse/DERBY-463?page=comments#action_12356742
> For org.apache.derby.client.am.ClobOutputStream#write(int), five objects are created
for every byte written.
> "In fact this class and the client Clob have code like this everywhere, as the Clob is
updated:
>         clob_.string_ = clob_.string_.concat(new String(newByte));
>         clob_.asciiStream_ = new java.io.StringBufferInputStream(clob_.string_);
>         clob_.unicodeStream_ = new java.io.StringBufferInputStream(clob_.string_);
>         clob_.characterStream_ = new java.io.StringReader(clob_.string_);
> Would probably be better to create most of those objects on demand, rather than on every
modification. I mean if the CLOB is modified
> but the application never retrieives the ascii  or character streams, what was the benefit
of creating them? "
> ________________
> Also check the org.apache.derby.client.am.ClobWriter.  Need to make this better and efficient.


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