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From "Aleksey Yeschenko (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-6426) Lost update in Prepared statement batch when a column is inserted with null value in the same batch just before
Date Sun, 01 Dec 2013 16:41:35 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-6426?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13836060#comment-13836060
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Aleksey Yeschenko commented on CASSANDRA-6426:
----------------------------------------------

There is a related CASSANDRA-6123, but it (probably) wouldn't affect batches.

> Lost update in Prepared statement batch when a column is inserted with null value in
the same batch just before
> ---------------------------------------------------------------------------------------------------------------
>
>                 Key: CASSANDRA-6426
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-6426
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>         Environment: Cassandra Server 2.0.3
> Java Driver Core 2.0.0-rc1
>            Reporter: DOAN DuyHai
>
> {panel:title=Test environment}
> Cassandra Server *2.0.3*
> Java Driver Core *2.0.0-rc1*
> {panel}
> While implementing batched prepared statements for Achilles, I ran into a very annoying
bug.
> {code:title=FailingUnitTest.java|borderStyle=solid}
> //Given
> Long id = RandomUtils.nextLong();
> session.execute("CREATE TABLE test(id bigint, name text,label text, PRIMARY KEY(id))");
> PreparedStatement insertPS = session.prepare("INSERT INTO test(id,name,label) VALUES
(?,?,?)");
> PreparedStatement updatePS = session.prepare("UPDATE test SET label=? WHERE id=?");
> // Notice the "label" column is inserted first with null
> BoundStatement insertBS = insertPS.bind(id, "myName", null);
> // Then "label" is updated to "myLabel"
> BoundStatement updateBS = updatePS.bind("myLabel", id);
> //When
> BatchStatement batch = new BatchStatement();
> batch.add(insertBS);
> batch.add(updateBS);
> session.execute(batch);
> //Then
> Statement statement = new SimpleStatement("SELECT * from test where id=" + id);
> Row row = session.execute(statement).one();
> // Assertion FAIL, "label" is NULL
> assertThat(row.getString("label")).isEqualTo("myLabel");
> {code}
>  The above code always fails.
>  Even if I switch the order of the bound statements, e.g. *updateBS* added to the batch
before *insertBS*, the test still fails.
> {code:title=WorkingUnitTest.java|borderStyle=solid}
> //Given
> Long id = RandomUtils.nextLong();
> session.execute("CREATE TABLE test(id bigint, name text,label text, PRIMARY KEY(id))");
> PreparedStatement insertPS = session.prepare("INSERT INTO test(id,name) VALUES (?,?)");
> PreparedStatement updatePS = session.prepare("UPDATE test SET label=? WHERE id=?");
> // Notice the "label" column is removed from the insert statement
> BoundStatement insertBS = insertPS.bind(id, "myName");
> BoundStatement updateBS = updatePS.bind("myLabel", id);
> //When
> BatchStatement batch = new BatchStatement();
> batch.add(updateBS);
> batch.add(insertBS);
> session.execute(batch);
> //Then
> Statement statement = new SimpleStatement("SELECT * from test where id=" + id);
> Row row = session.execute(statement).one();
> // Assertion SUCCEEDS here
> assertThat(row.getString("label")).isEqualTo("myLabel");
> {code}
>  Only removing column "label" from the first insert bound statement can make the test
succeed. This is pretty annoying. 
>  The rationale for inserting null values is that in Achilles I prepare generic insert
statements for all entities and setting NULL when the field is not filled at runtime.
>  Currently, there is no guarantee for batch of prepared statement to be executed in the
order they are declared.



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