[DERBY-684] Improve performance of Clob objects (ClobOutputStream#write,ClobWriter#write) on the client

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Won't Fix
• Affects Version/s: 10.1.1.0, 10.1.2.1, 10.2.1.6
• Component/s: Network Client
• Environment: all
• Bug behavior facts: Performance
• Assignee: Unassigned
• Reporter: Sunitha Kambhampati
• Created: 05/Nov/05 11:08
• Updated: 29/Jun/09 14:44
• Resolved: 19/Nov/08 17:13

Description

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.

Issue Links

• is related to: DERBY-1256 Remove usage of non-portable methods in derby code
• is related to: DERBY-1615 Rewrite the Clob implementation in the client driver