marschall / jfr-jdbctemplate

an implementation of Spring JdbcTemplate that generates Flight Recorder events

JFR JdbcTemplate

An implementation of Spring JdbcTemplate that generates Flight Recorder events.

This project requires Java 11 based on OpenJDK or later.

<dependency>
  <groupId>com.github.marschall</groupId>
  <artifactId>jfr-jdbctemplate</artifactId>
  <version>2.0.0</version>
</dependency>

Versions 1.x are intended for Spring 5.x / Java 11, versions 2.x are intended for Spring 6.x / Java 17.

Compared to approaches based on DataSource an approach based on JdbcTemplate has the advantage that it captures a complete database interaction. For example if you process many rows the initial PreparedStatement#execute() might be fast but most of the time may be spent in ResultSet#next(). A JdbcTemplate based approach generates a single JFR event for the entire interaction that involves several JDBC method invocations.

Spring Class	JFR Class
org.springframework.jdbc.core.JdbcOperations	com.github.marschall.jfr.jdbctemplate.JfrJdbcOperations
org.springframework.jdbc.core.namedparam.NamedParameterJdbcOperations	com.github.marschall.jfr.jdbctemplate.JfrNamedParameterJdbcOperations

Reported Attributes

operationName

The name of the execute JDBC operation, this corresponds to the method name on JdbcOperations/JdbcTemplate.

query

The SQL query string passed to the JDBC driver. May be missing especially if custom org.springframework.jdbc.core.PreparedStatementCreator fail to implement org.springframework.jdbc.core.SqlProvider.

rowCount

In the case of a SELECT the number of rows returned. In the case of an UPDATE or DELETE the number of rows affected. -1 for a statement that does not return anything like a DDL. -2 when no information about the number of rows is available.

Overhead

We try to keep overhead to a minimum and have no additional allocations besides the JFR events. Besides the overhead of the event the only additional overhead is:

• a wrapper around JdbcTemplate
• a few instanceof operations and casts
• a finally block
• a capturing lambda for #queryForStream methods to record Stream#close as the end time of the event
• a small wrapper around every RowCallbackHandler

We assume org.springframework.jdbc.core.SqlProvider#getSql() is a simple getter.

Usage

@Configuration
public class JdbcConfiguration {

   @Autowired
   private DataSource dataSource;

   @Bean
   public JdbcOperations jdbcOperations() {
     return new JfrJdbcOperations(new JdbcTemplate(this.dataSource));
   }

   @Bean
   public NamedParameterJdbcOperations namedParameterJdbcOperations() {
     return new JfrNamedParameterJdbcOperations(new NamedParameterJdbcTemplate(this.jdbcOperations()));
   }

}

You need something like the following JVM options to run Flight Recorder

-XX:StartFlightRecording:filename=recording.jfr
-XX:FlightRecorderOptions:stackdepth=128

Limitations

• When the SQL query is not provided as a String but as a PreparedStatementCreator or CallableStatementCreator it has to implement SqlProvider for the query string to show up in the flight recording.
• JdbcTemplate#query(PreparedStatementCreator, PreparedStatementSetter, ResultSetExtractor) is not available because it is defined on JdbcTemplate and not JdbcOperations.
• Several spring-jdbc classes AbstractJdbcCall, SimpleJdbcCall, StoredProcedure, RdbmsOperation, AbstractJdbcInsert, SimpleJdbcInsert but also JdbcTestUtils and JdbcBeanDefinitionReader require a JdbcTemplate and do not work with JdbcOperations. We have a pull request open for this but it has not been merged yet.
• JdbcOperations#execute(ConnectionCallback) can not provide any insight into what is executed inside, that would require integration with marschall/jfr-jdbc