Hi all,
It seems that org.postgresql.Driver isn't thread safe, as it stores details
from the connection URL to the connect method in an instance variable
"props" - and there is no synchronisation. The DriverManager
(java.sql.DriverManager) returns the same instance of the
org.postgresql.Driver to each getDriver(String url ) method and probably all
of the others. Hence the problem with multiple threads connecting at the
same time, the threads obtain the same Driver instance and the connection
details from different threads can become muddled.
I observed this bug on my production server using Jakarta Tomcat 4.1.27 and
Jakarta Commons DBCP 1.0 which uses the DriverManager.getDriver(String url)
method to obtain a Driver object, and then calls the connect method on the
driver. The getConnection() method in DriverManager are all synchronized so
it is the getting of the Driver and then calling connect on that which has
revealed this issue.
I've made a simple patch against the REL_7_3_STABLE branch of Driver.java.in
which removes the use of the instance variable. I'm going to test this patch
immediately.
Kind regards,
Karl
cvs diff Driver.java.in (in directory
C:\DEVELOPMENT\pgsql\src\interfaces\jdbc\org\postgresql)
Index: Driver.java.in
===================================================================
RCS file:
/projects/cvsroot/pgsql-server/src/interfaces/jdbc/org/postgresql/Driver.jav
a.in,v
retrieving revision 1.22.2.7
diff -r1.22.2.7 Driver.java.in
109a110
> Properties props;
122c123
< con.openConnection (host(), port(), props,
database(), url, this);
---
> con.openConnection (host(props), port(props), props,
> database(props), url, this);
232,233d232
< private Properties props;
<
350c349
< public String host()
---
> public String host(Properties props)
358c357
< public int port()
---
> public int port(Properties props)
366c365
< public String database()
---
> public String database(Properties props)
375c374
< public String property(String name)
---
> public String property(Properties props, String name)
394c393
< * @param int logLevel sets the level which logging will
respond to
---
> * @param logLevel sets the level which logging will respond to
