Using JDBC, setting new attribute multiple times results in an UPDATE not an INSERT

[candrews]

When using JDBC, setting a new attribute multiple times results in an SQL UPDATE not an INSERT. Because there is no row to update, the session attribute is not actually saved to the table.

For example, in a request handler (a Spring MVC controller, servlet, filter, etc):

Assert.isTrue(request.getSession().getAttribute("test")==null);
request.getSession().setAttribute("test", "someValue");
request.getSession().setAttribute("test", "someValue");

I would expect a row to be added to the SPRING_SESSION_ATTRIBUTES table with the ATTRIBUTE_NAME of "test" and the ATTRIBUTE_VALUE of "someValue"

However, what actually happens is that an UPDATE statement is executed resulted in no row being added to SPRING_SESSION_ATTRIBUTES.

The problem appears to be at https://github.com/spring-projects/spring-session/blob/2.0.3.RELEASE/spring-session-jdbc/src/main/java/org/springframework/session/jdbc/JdbcOperationsSessionRepository.java#L738 - I believe the line should be:

else if (this.delta.get(attributeName) != DeltaValue.ADDED && this.delegate.getAttribute(attributeName) != null) {

[candrews]

Opened a pull request: #1070

[candrews]

An alternative solution would be to use an UPSERT for the update SQL instead of an UPDATE... but there's no standard UPSERT support in the SQL standard, so that's probably not a workable approach.

[vpavic]

Thanks for the report @candrews! Closing in favor of PR #1070.