Wildfly 8.2 ResultSet hangs

[pkolaric]

Hello,

We've stumbled upon a strange ?bug? that causes a ResultSet.next() to hang.

Requirements:

- query a table with more records than fetchSize

- execute a second query on the _same_ connection as the previous one

The first ResultSet.next() will fail (just hang, without any exception) when it reaches the "fetchSize" count.

It is reproducable by this code snippet which works fine outside of wildfly, but not in wildfly.

try (Connection conn = ds.getConnection()) {

                try (PreparedStatement ps = conn.prepareStatement("SELECT * FROM some_table")) {

                    ps.setFetchSize(1000);

                    try (ResultSet rs = ps.executeQuery()) {

                        int i=0;

                        while (rs.next()) {

                            i++;

                            if (i==800) {

                                try (PreparedStatement ps2 = conn.prepareStatement("SELECT * FROM other_table WHERE id=10")) {

                                    try(ResultSet rs2 = ps2.executeQuery()) {

                                        while (rs2.next()) {

                                            System.out.println("got data!");

                                        }

                                    }

                                }

                            }

                            if (i % 100 == 0) {

                                System.out.println("i="+i);

                            }

                        }

                    }

                }

            }

I've tested in on Wildfly8.2 and Wildfly9.

The database is postgres 9.2

The JDBC driver is pgjdbc-ng 0.5 (http://impossibl.github.io/pgjdbc-ng/get.html)

Is this a bug in wildfly (IronJacamar) or am i doing something wrong?

[pmm]

Can you reproduce this in a standalone Java SE application with just pgjdbc-ng and without any connection pool?

[pkolaric]

I've actually figured it out.

It starts to work if you explicitly set AutoCommit to false on the connection as soon as you request it from datasource.

autoCommit=true shouldn't exist anyway

[pmm]

Why do you have to set auto commit to false in WildFly? Shouldn't this be the default?