Optimistic Locking and DAOs does not work

[Simon Martinelli]

Hi,

I've configured optimistic locking:

@Configuration
public class SakilaJooqConfiguration {

@Bean
public DefaultConfigurationCustomizer configurationCustomizer() {
    return (DefaultConfiguration c) -> c.settings()
        .withExecuteWithOptimisticLocking(true);
    }
}

Now I try to use a DAO with a POJO to read and update:

var rentalDao = new RentalDao(dsl.configuration());

rentalDao.findOptionalById(854L).ifPresent(rental -> {
    rental.setRentalDate(LocalDateTime.now());
    rentalDao.update(rental);
});

But this leads to 

org.jooq.exception.DataChangedException: Database record has been changed

at org.jooq.impl.UpdatableRecordImpl.checkIfChanged(UpdatableRecordImpl.java:507)
at org.jooq.impl.UpdatableRecordImpl.storeMergeOrUpdate0(UpdatableRecordImpl.java:345)
at org.jooq.impl.UpdatableRecordImpl.storeUpdate0(UpdatableRecordImpl.java:240)
at org.jooq.impl.UpdatableRecordImpl.lambda$storeUpdate$1(UpdatableRecordImpl.java:232)
at org.jooq.impl.RecordDelegate.operate(RecordDelegate.java:144)
at org.jooq.impl.UpdatableRecordImpl.storeUpdate(UpdatableRecordImpl.java:231)
at org.jooq.impl.UpdatableRecordImpl.update(UpdatableRecordImpl.java:168)
at org.jooq.impl.UpdatableRecordImpl.update(UpdatableRecordImpl.java:163)
at org.jooq.impl.DAOImpl.update(DAOImpl.java:210)
at org.jooq.impl.DAOImpl.update(DAOImpl.java:186)

When I debug into UpdatableRecordImpl I see that in the record only the id is set.

Is this a bug or did I miss somehting?

Thanks, 

Simon

[Lukas Eder]

Hi Simon,

What column(s) did you configure for your optimistic locking checks? What SQL queries are being generated in your debug logs?

Best Regards,

Lukas

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[Simon Martinelli]

I didn't configure any column so it should use all columns.

You can try it yourself: https://github.com/simasch/jooq-workshop

(Make sure Docker is running locally)

That's the test that causes the problem:

https://github.com/simasch/jooq-workshop/blob/main/jooq-sakila/src/test/java/ch/martinelli/edu/jooq/sakila/exercise/Ex06DaosTest.java

[Lukas Eder]

Thanks, I will, soon

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[Lukas Eder]

Thanks for your patience. I've had a look at this issue and created a ticket here with some more details:

https://github.com/jOOQ/jOOQ/issues/15115

I don't think jOOQ can do much about this case. jOOQ doesn't know which fields you've changed in your POJO (rental.setRentalDate()) and which fields have been changed in the database, because unlike the UpdatableRecord, the POJO doesn't keep any dirty flags. That's the point of the POJO types. However, there might be an argument in favour of ignoring the optimistic locking feature when:

- An UpdatableRecord was not "fetched" (i.e. created entirely in the client, e.g. from a POJO as in your case)

- When we're using unversioned optimistic locking (because with versioned rows, this problem wouldn't happen)

Thoughts?

[Lukas Eder]

... on second thought, I don't think we should ignore the feature and store the record silently. Much rather, a different error message ("can't lock this particular record") would help explain the problem.

[Simon Martinelli]

Hi Lukas,

Thanks for the explanation.

Yes, I think a more expressive error message would be helpful.

Thanks, Simon

[Lukas Eder]

https://github.com/jOOQ/jOOQ/issues/15115 (an improved error message and javadoc on the DataChangedException) has been implemented for 3.19.0, 3.18.5, 3.17.14, 3.16.20