Hi Luke,
Thanks for your reply. I tried to opt for OL as you have mentioned , in the
following code:
public void runQueries2() {
String userName = "bidev";
String password = "biapp";
String url = "jdbc:postgresql://localhost:5432/postgres";
try {
Connection conn = DriverManager.getConnection(url, userName,
password)
Configuration configuration = new DefaultConfiguration()
.set(conn)
.set(SQLDialect.POSTGRES);
configuration.settings().withExecuteWithOptimisticLocking(true);
conn.setAutoCommit(false);
Connection conn1 = DriverManager.getConnection(url, userName,
password);
conn1.setAutoCommit(false);
Configuration configuration1 = new DefaultConfiguration()
.set(conn1)
.set(SQLDialect.POSTGRES);
configuration1.settings().withExecuteWithOptimisticLocking(true);
DSLContext context = DSL.using(configuration);
DSLContext context1 = DSL.using(configuration1);
context1.update(Layout.LAYOUT)
.set(Layout.LAYOUT.HEIGHT,200)
.where(Layout.LAYOUT.ID.eq(1L))
.returning(Layout.LAYOUT.ID)
.fetchOne();
context.update(Layout.LAYOUT)
.set(Layout.LAYOUT.HEIGHT,10)
.where(Layout.LAYOUT.ID.eq(1L))
.returning(Layout.LAYOUT.ID)
.fetchOne();
conn.commit();
conn1.commit();
}
//TODO: should be throwing it back..
catch (Exception e) {
e.printStackTrace();
}
}
But the code does end up in a deadlock. Note that here I'm just mimicking
the scenario. Layout schema looks like the following:
CREATE TABLE LAYOUT(
ID BIGSERIAL PRIMARY KEY NOT NULL,
DID SERIAL REFERENCES DATASOURCE (ID),
VERSION_ID INTEGER,
TYPE VARCHAR(30) NOT NULL,
QUERY VARCHAR(500) NOT NULL,
WIDTH INTEGER,
HEIGHT INTEGER,
POSIITION INTEGER,
LAYOUT JSONB NULL
);
and the in the code generation I have used the following:
<recordVersionFields>VERSION_ID</recordVersionFields>
Not sure, where I'm making the mistake.
On Mon, Sep 4, 2017 at 3:19 PM, Lukas Eder <[email protected]> wrote:
> Hi Kamal,
>
> Thanks for your message. I'll comment inline
>
> 2017-09-03 16:38 GMT+02:00 Kamal raj <[email protected]>:
>
>> 1. Need to enable the OL in Jooq using executeWithOptimisticLocking
>> settings
>>
>
> Yes
>
>
>> 2. Since OL in Jooq automatically throws / fails when see the concurrent
>> modification, I believe its totally fine to run them in any transaction
>> mode (note that I'm using Postgres here). My understanding here is that OL
>> themselves hides the complexity of transaction. May be I'm wrong here.
>> Please correct me.
>>
>
> Well, to get a completely accurate picture, the usual transaction
> anomalies can still happen under non-serializable transaction isolation -
> although, I cannot think of such an edge case right now.
>
>
>> 3. How does Jooq knows which column it needs to watch while versioning
>> under OL? The documentation from here : https://www.jooq.org/doc/2.5
>> /manual/sql-execution/crud-with-updatablerecords/optimistic-locking/
>> says that, we can create a column called MODIFIED as a TIMESTAMP. But the
>> question here is, how does the column mapping works w.r.t to OL?
>>
>
> Follow the link to the manual sections about the code generator
> configuration. You can specify the columns to be used as version /
> timestamp columns here:
> https://www.jooq.org/doc/latest/manual/code-generation/
> codegen-advanced/codegen-config-record-version-timestamp-fields
>
> I hope this helps,
> Lukas
>
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