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From "Myrna van Lunteren (JIRA)" <j...@apache.org>
Subject [jira] Commented: (DERBY-684) Improve performance of Clob objects (ClobOutputStream#write,ClobWriter#write) on the client
Date Tue, 18 Nov 2008 19:15:44 GMT

    [ https://issues.apache.org/jira/browse/DERBY-684?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12648709#action_12648709
] 

Myrna van Lunteren commented on DERBY-684:
------------------------------------------

I've looked at what's remaining of this code, and it appears to me it's only still used when
interfacing with servers without loblocator support. 
Which means it'd be harder to test (only with cross-version server/client testing, which we
currently don't do automated), and it'd be work that only would affect a small number of customers.

I suggest we close this issue - the improvement of making the streams on demand, rather than
on write - with no fix intended.
(The StringBufferInputStream is listed, and should be viewed under, DERBY-1256, not under
this section).

> 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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