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Date: Fri, 26 Jun 2009 08:49:07 -0700 (PDT)
From: "Dag H. Wanvik (JIRA)" <jira@apache.org>
To: derby-dev@db.apache.org
Subject: [jira] Updated: (DERBY-1017) locking issue with a select statement
 using an order by clause
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     [ https://issues.apache.org/jira/browse/DERBY-1017?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Dag H. Wanvik updated DERBY-1017:
---------------------------------

    Attachment: selfContainedRepro.zip

I hacked the repro with DDL ops, so it runs self contained.

Additional data point: If I user the optimizer override to force use of the index in ConnB, the query does not hang:

String sql = "SELECT au_id, au_lname, au_fname, phone, contract FROM authors  --DERBY-PROPERTIES index=firstnameindex" + "\n where au_lname = ? ORDER BY au_fname";


> locking issue with a select statement using an order by clause
> --------------------------------------------------------------
>
>                 Key: DERBY-1017
>                 URL: https://issues.apache.org/jira/browse/DERBY-1017
>             Project: Derby
>          Issue Type: Bug
>          Components: SQL
>    Affects Versions: 10.0.2.0
>         Environment: Windows XP Professional operating system and Java2 platform using JDK 5.0
>            Reporter: Mark H. Kaplan
>         Attachments: derbyLocking.zip, selfContainedRepro.zip
>
>
> I am using the network version of Derby (version 10 - the network version). I am running two threads. The first thread is doing an insert into a table but not committing. The second table is doing a select statement. When the select statement has an order by clause, it will not complete but when it does not have the order by clause, it completes while the first thread is sleeping.
> The database contains one table with five columns. I have tried having an index on the order by column but that does not seem to make a difference. I have not set any isolation level on the database so it is using the default of TRANSACTION_READ_COMMITTED.
> The insert statement in the first thread looks like:
> INSERT INTO Authors (au_id, au_lname, au_fname, phone, contract) VALUES ('999-99-9999', 'last', 'first', 'xxx-xxxx', 0)
> The select statement in the second thread looks like:
> SELECT au_id, au_lname, au_fname, phone, contract FROM authors where au_lname = 'xxx' ORDER BY au_fname
> MORE INFORMATION --
> My order by select statement does timeout with the error 40XL1. I tried putting an index on the au_fname but that did not make a difference
> I have included locking data which I retrieved by running a  "SELECT * FROM NEW org.apache.derby.diag.LockTable() AS LT" while the second thread was doing its SELECT statement. I do not understand the data but I thought that it might give you a better idea of what is going on. I have also included the database sql script that creates the database table and the two sql statements that I am running in separate threads to give you a better idea of what I am doing. Let me know if you need any other information:
> (Locking Data)
> XID |TYPE |MODE |TAB |LOCK |STATE |TABLETYPE |LOCK& |INDEXNAME
> ===
> 302 |ROW |X |AUTHORS |(2,18) |GRANT |T |1 |null
> 302 |ROW |X |AUTHORS |(1,7) |GRANT |T |1 |null
> 304 |ROW |S |AUTHORS |(1,7) |WAIT |T |0 |null
> 302 |TABLE |IX |AUTHORS |Tablelock |GRANT |T |3 |null
> 304 |TABLE |IS |AUTHORS |Tablelock |GRANT |T |1 |null
> (SQL Script)
> DROP TABLE authors;
> CREATE TABLE authors (
> au_id VARCHAR(32) NOT NULL,
> au_lname VARCHAR(40) ,
> au_fname VARCHAR(20) ,
> phone VARCHAR(12) ,
> contract INT NOT NULL,
> PRIMARY KEY (au_id)
> );
> CREATE INDEX firstnameindex ON authors (au_fname);
> (SQL Statements)
> Thread 1 - INSERT INTO Authors (au_id, au_lname, au_fname, phone, contract) VALUES ('999-99-9999', 'last', 'first', 'xxx-xxxx', 0)
> Thread2 - SELECT au_id, au_lname, au_fname, phone, contract FROM authors where au_lname = 'xxx' ORDER BY au_fname

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