Performance degradation after upgrading Hibernate from 6 to 7 cause of early acquisition of physical connection

Hibernate ORM
1

Hi all!

I discovered that my application’s performance had degraded by about 15% after 6->7 upgrade. After some investigation, I found the cause: early acquisition of physical connection for each SELECT query.

JdbcSelectExecutorStandardImpl.java#L132

I propose optimizing this method.

Acquire the connection only when both conditions are met:

  1. jdbcSelect instance of JdbcSelectWithActions
  2. The set of pre and post actions is not empty

Is it possible to discuss this improvement? I can provide a test case if needed.

2

Sure, please provide a test case and explain what you found during your analysis.

3

I have a wrapper around the connection that sets its name via a SQL query (PostgreSQL):

select 1 from set_config('application_name',?, false)

This query is executed every time a connection is opened. Compared to version 6, the number of SELECT queries has increased several-fold (and total execution time).

Hibernate 6:

hib6
hib62280×562 62.6 KB

Hibernate 7:

hib7
hib72260×542 58.5 KB

And the connection opens even with a fast query cache. The presence of a connection pool has no effect on the result (using Hikari).

I don’t know how to attach test case here as file (probably can to jira).

4

Thanks for the insight. The increase of the query count is unfortunate, but can have many reasons. Please try to create a reproducer with our test case template and if you are able to reproduce the issue, create a bug ticket in our issue tracker and attach that reproducer.