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From "Mark H. Kaplan (JIRA)" <derby-...@db.apache.org>
Subject [jira] Created: (DERBY-1017) locking issue with a select statement using an order by clause
Date Tue, 21 Feb 2006 18:57:27 GMT
locking issue with a select statement using an order by clause
--------------------------------------------------------------

         Key: DERBY-1017
         URL: http://issues.apache.org/jira/browse/DERBY-1017
     Project: Derby
        Type: Bug
  Components: Network Server  
    Versions: 10.0.2.0    
 Environment: Windows XP Professional operating system and Java2 platform using JDK 5.0
    Reporter: Mark H. Kaplan


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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