Why is hibernate so slow

So, the slow query log validates the underlying SQL query execution without taking into account how the ResultSet is transformed into entities, DTOs, Tuple instances, or the default Object[] array. Next, we are going to check how the SQl query logs work for both entity queries and native SQL statements. The slow query threshold was set to 25 milliseconds, and, since the above SQL query took more than that, Hibernate added a slow query log entry.

Notice that the log entry was formatted on multiple lines to increase readability for this article. However, by default, there will be a single line of text containing the slow query log entry. Writing Criteria API queries is not very straightforward. Check out this article for more details about this topic.

The Hibernate 5. As per the source code of SqlStatementLogger. For our needs, I wrote a bash script using cut and sed to transform the slow sql logs ouput to a csv with only the needed data. Maybe my hibernate. Asked By: bentrm. Answered By: Darryl Miles. Answered By: Ricardo Spinoza. Answered By: kidfruit. Answered By: Mirko Adari.

Hibernate transaction not successfully started. MappingException: Unable to find column with logical name. Is it mandatory to have hibernate. Hibernate uses a lot of internal optimizations and hides all database interactions behind its API. This post will show you how to detect Hibernate performance issues when your application is in development and production. That makes it hard to find inefficiencies and potential performance problems before they cause trouble in production.

The best way to avoid these Hibernate performance issues is to monitor the database interactions during development, test and production. There are lots of different ways you can do that. All of these options can help you better understand how Hibernate interacts with the database.

However, you should choose the tool you feel most comfortable with. Hibernate writes log messages telling you:. As most frameworks and applications, Hibernate uses different categories and log levels to log this information. The best way to activate the logging of executed SQL queries is to set the log level of the category org.

Hibernate uses the configured logging framework to write the messages to the log file, and you can change it at any time without changing your deployed application. You can see an example of a log4j configuration in the following code snippet, and you can fork the project with this and all following code snippets on github. When you activate this logging configuration, Hibernate will write a log message for each executed SQL statement.

The logging of all executed queries provides basic information about all database interactions, but Hibernate can do a lot more. If you enable the Hibernate statistics component, it measures how long it takes to execute a query and summarizes the executed queries and execution times at the end of each session. That makes it a lot easier to get a general overview of your application and helps you to identify the sessions you should take a closer look at.

But be careful. You can activate the statistics component by setting the system property usihibernate. Hibernate will then write a summary of all database interactions at the end of each session. This seems insane, since it should already have all the results after 1 query. Hibernate logs do not show any additional SQL being issued during all that time. I finally managed to get to the bottom of this. The problem was being caused by Hibernate setting the parameters separately from the actual SQL query that involved subqueries.

So native SQL or not, the performance will be slow if this is done. For example this will be slow:. It seems that for some reason with letting Hibernate take care of the parameters it ends up getting stuck in the resultSet fetching.

This is probably because the underlying query on the database is taking much longer being parameterized.

I ended up writing the equivalent of Hibernate Criteria and Restrictions code that sets the parameters directly as above. And also encountered that writing the query with hardcoded parameters instead of using setParameter would fixed the issue.

We are using MS SQL Server and after further investigation we noticed the the root cause of our issue is a default configuration of the sql server driver that transmits the query parameters as unicode. This lead to our indices being ignored since they were based on the ascii values on the queried columns. More details can be found here.

Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more.