Very Dangerous bug in XA connection pooling and SL EJBs with jboss-4.2.3 & latest postgresql-8.4-701.jdbc3.jar - Mailing list pgsql-jdbc
From | Achilleas Mantzios |
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Subject | Very Dangerous bug in XA connection pooling and SL EJBs with jboss-4.2.3 & latest postgresql-8.4-701.jdbc3.jar |
Date | |
Msg-id | 201003021629.07368.achill@matrix.gatewaynet.com Whole thread Raw |
Responses |
Re: Very Dangerous bug in XA connection pooling and SL EJBs
with jboss-4.2.3 & latest postgresql-8.4-701.jdbc3.jar
|
List | pgsql-jdbc |
Introduction ======== This bug has the potential effect of xactions which under certain condition should rollback, to behave as if autocommit is true. The workaround is to use local-tx-datasource with the standard driver org.postgresql.Driver instead of xa-datasource with org.postgresql.xa.PGXADataSource. The description below is with FreeBSD diablo-1.5 , but its exactly the same with SLES 10 SP1 and 1.5.0_15. configuration ============== server/default/deploy/postgres-xa-ds.xml ------------------------------------------------------------------- <datasources> <xa-datasource> <jndi-name>pgsql</jndi-name> <use-java-context>true</use-java-context> <xa-datasource-class>org.postgresql.xa.PGXADataSource</xa-datasource-class> <xa-datasource-property name="ServerName">localhost</xa-datasource-property> <xa-datasource-property name="PortNumber">5432</xa-datasource-property> <xa-datasource-property name="DatabaseName">dynacom</xa-datasource-property> <xa-datasource-property name="User">postgres</xa-datasource-property> <xa-datasource-property name="Password">xxxxx</xa-datasource-property> <xa-datasource-property name="Compatible">8.2</xa-datasource-property> <track-connection-by-tx/> <min-pool-size>1</min-pool-size> <max-pool-size>2</max-pool-size> <metadata> <type-mapping>PostgreSQL 8.0</type-mapping> </metadata> </xa-datasource> </datasources> Description ======== Consider the following test case: This code is executed: StatusHome sthome = (StatusHome) ic.lookup("java:comp/env/ejb/Status"); Status stat = sthome.create(); "Status" is a SL Session EJB, which is defined to run with @ejb.transaction type = "Required" Whenever the above is executed, i see in pgsql log: postgres [23247] 2010-03-02 16:04:09.377 EET line:8 LOG: execute S_1: BEGIN postgres [23247] 2010-03-02 16:04:09.378 EET line:9 LOG: execute <unnamed>: select .... postgres [23247] 2010-03-02 16:04:09.380 EET line:11 LOG: execute S_2: COMMIT which is correct behaviour. Then the following code (lets name it sql_xact) is executed: sql_xact: try { DataSource ds = (javax.sql.DataSource) ic.lookup("java:comp/env/jdbc/DynacomDB"); con = ds.getConnection(); con.setAutoCommit(false); st = con.prepareStatement("select now();"); rs = st.executeQuery(); rs.close(); st.close(); con.commit(); } catch (Exception e) { out.println("<BR>\n"); out.println("Error: " + e.getMessage()); con.rollback(); e.printStackTrace(); } finally { if (con != null) con.close(); } If the above is executed on the same postgresql backend and immediately after the previous (EJB call) block of code, i seein pgsql log: postgres [23247] 2010-03-02 16:07:24.088 EET line:24 LOG: execute <unnamed>: select now() which means no begin-commit/rollback block. at this point a xaction supposed to rollback, is semi-commited. Now, If however, i execute this block of code: try { DataSource ds = (javax.sql.DataSource) ic.lookup("java:comp/env/jdbc/DynacomDB"); con = ds.getConnection(); con.setAutoCommit(true); st = con.prepareStatement("select now();"); rs = st.executeQuery(); rs.close(); st.close(); } catch (Exception e) { out.println("<BR>\n"); out.println("Error: " + e.getMessage()); e.printStackTrace(); } finally { if (con != null) con.close(); } and then sql_xact code again, then the connection gets back to normal, pgsql log looking like: postgres [23247] 2010-03-02 16:11:57.729 EET line:39 LOG: execute S_1: BEGIN postgres [23247] 2010-03-02 16:11:57.729 EET line:40 LOG: execute <unnamed>: select now() postgres [23247] 2010-03-02 16:11:57.730 EET line:41 LOG: execute S_2: COMMIT I dont think that the usage of XA connections are critical for our case, so i can live with local connections (although iguess i have a lot of garbage data since the above setup was deployed some 2 years ago.... imagine if i were selling open sourceto some bank) Any thoughts as to where the problem might reside? The jboss camp or the pgsql-jdbc camp? -- Achilleas Mantzios
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