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From "Daniel John Debrunner (JIRA)" <derby-...@db.apache.org>
Subject [jira] Commented: (DERBY-782) Improvement on org.apache.derby.impl.jdbc.EmbedBlob#length()
Date Tue, 02 May 2006 23:49:48 GMT
    [ http://issues.apache.org/jira/browse/DERBY-782?page=comments#action_12377499 ] 

Daniel John Debrunner commented on DERBY-782:
---------------------------------------------

The change 397313 includes as you say saving the length of the stream if it has to read the
entire length,
but in addition it has this change.

@@ -221,6 +229,14 @@
                     setupContextStack();
 
                 setPosition(0);
+                // If possible get the length from the encoded
+                // length at the front of the raw stream.
+                if ((myLength = biStream.getLength()) != -1) {
+                    biStream.close();
+                   return myLength;
+                }
+                

Then, I'm sorry I missed referencing additional changes from DERBY-438.

SVN change 394109
This change makes the binary length encoded in the on-disk format  be written correctly when
the length is known.
http://svn.apache.org/viewcvs?view=rev&rev=394109

SVN Change 393880
This change saves the encoded length when reading the stream from the disk,
this is then used by EmbedBlob in the 397313 change
http://svn.apache.org/viewcvs?view=rev&rev=393880

Thanks for keeping me honest.

> Improvement on org.apache.derby.impl.jdbc.EmbedBlob#length()
> ------------------------------------------------------------
>
>          Key: DERBY-782
>          URL: http://issues.apache.org/jira/browse/DERBY-782
>      Project: Derby
>         Type: Bug

>   Components: JDBC
>     Reporter: Tomohito Nakayama
>      Fix For: 10.2.0.0
>  Attachments: testLob4.java
>
> Now, org.apache.derby.impl.jdbc.EmbedBlob#length() method read out whole  BinaryToRawStream
to know exact length.
> On the other hand,  BinaryToRawStream have some commented-out inplementation of having
information for length.
> I think the information of lengh in BinaryToRawStream should be restored to be used in
.org.apache.derby.impl.jdbc.EmbedBlob#length(), because read out whole stream can be expensive
processing when streamed information was large.
> There exists a subject that reliability of lengh information in BinaryToRawStream is
unknown.

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