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Date: Tue, 28 Jun 2011 09:48:17 +0000 (UTC)
From: "Kristian Waagan (JIRA)" <jira@apache.org>
To: derby-dev@db.apache.org
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Subject: [jira] [Assigned] (DERBY-5090) Retrieving BLOB fields sometimes
 fails
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     [ https://issues.apache.org/jira/browse/DERBY-5090?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Kristian Waagan reassigned DERBY-5090:
--------------------------------------

    Assignee: Kristian Waagan

> Retrieving BLOB fields sometimes fails
> --------------------------------------
>
>                 Key: DERBY-5090
>                 URL: https://issues.apache.org/jira/browse/DERBY-5090
>             Project: Derby
>          Issue Type: Bug
>          Components: JDBC
>    Affects Versions: 10.7.1.1
>         Environment: JDBC derby embedded driver
>            Reporter: Unai Vivi
>            Assignee: Kristian Waagan
>              Labels: BLOB, exception, null, read
>         Attachments: Derby5090.java, Derby5090_2.java, Derby5090_3.java
>
>
> This is my first issue report, so please be understanding if I'm posting the wrong thing, in the wrong place or in the wrong way. I just want to help. :)
> While iterating through a ResultSet, when accessing a BLOB field to read its contents via an InputStream, I noticed that:
> - if the current ResultSet's has been "warmed up" by retrieving another column first, everything it's fine;
> - if, on the other hand, you first-thing access the BLOB (and read other columns later), then upon reading the first byte out the InputStream bound to the BLOB field (ResultSet.getBinaryStream("col_name")) an IOException is thrown (and IOException's getMessage() method returns null).
> Following is an example, taken from a real application. The two code segments only differ in the fact that a SMALLINT & VARCHAR read is done before/after the BLOB read.
> --Working snippet--
> [...]
>                     icRelPath[i] = "imm" + File.separator + "ic" + "_" + rs.getShort("setIcone") + "_" + i + "." + rs.getString("estensione");
>                     AutoCloseInputStream acis = new AutoCloseInputStream(rs.getBinaryStream("ic" + i));
>                     if (rs.wasNull())
>                         icRelPath[i] = null;
>                     else
>                     {
>                         //icRelPath[i] = "imm" + File.separator + "ic" + "_" + rs.getShort("setIcone") + "_" + i + "." + rs.getString("estensione");
>                         BufferedInputStream bis = new BufferedInputStream(acis);
>                         int b = bis.read();//READS FINE
> [...]
> --Broken snippet--
> [...]
>                     //icRelPath[i] = "imm" + File.separator + "ic" + "_" + rs.getShort("setIcone") + "_" + i + "." + rs.getString("estensione");
>                     AutoCloseInputStream acis = new AutoCloseInputStream(rs.getBinaryStream("ic" + i));
>                     if (rs.wasNull())
>                         icRelPath[i] = null;
>                     else
>                     {
>                         icRelPath[i] = "imm" + File.separator + "ic" + "_" + rs.getShort("setIcone") + "_" + i + "." + rs.getString("estensione");
>                         BufferedInputStream bis = new BufferedInputStream(acis);
>                         int b = bis.read();//THROWS IOException WITH A null ERROR MESSAGE STRING
> [...]

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