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Posted to derby-dev@db.apache.org by "Kristian Waagan (JIRA)" <ji...@apache.org> on 2011/08/09 14:49:27 UTC
[jira] [Updated] (DERBY-5090) Retrieving BLOB fields sometimes
fails
[ https://issues.apache.org/jira/browse/DERBY-5090?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Kristian Waagan updated DERBY-5090:
-----------------------------------
Attachment: releaseNote.html
Committed patch 3a to trunk with revision 1155332.
Attaching the first attempt at a release note.
> 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, derby-5090-1a-fix.diff, derby-5090-1a-fix.stat, derby-5090-1b-fix.diff, derby-5090-2a-test.diff, derby-5090-2a-test.stat, derby-5090-3a-change_messages.diff, releaseNote.html
>
>
> 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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