Hibernate Batch Sequence Generator

A batch sequence generator for Hibernate that uses recursive queries to preallocate multiple values in a single database access.

The code is also present in Hibernate Types starting with version 2.13.1.

<dependency>
  <groupId>com.github.marschall</groupId>
  <artifactId>hibernate-batch-sequence-generator</artifactId>
  <version>2.1.1</version>
</dependency>

Versions 2.1.x support Hibernate 6.4.

Versions 2.0.x support Hibernate 6.x.

Versions 1.x support Hibernate 5.6.

This sequence generator combines the advantages of several existing sequence generators and avoids their disadvantages:

• hi/lo
  • all database access has to be aware of it
  • there is no clear relationship between the current sequence value and the column value
• pooled and pooledlo
  • INCREMENT BY has to be set on the database sequence
  • direct use of the sequence can cause a lot of identifier waste
  • the pool size and the INCREMENT BY value need to match
• IDENTITY
  • does not support JDBC batch inserts
• TABLE
  • has bad write performance

The limitations of this sequence generator are:

• limited database dialect support (see below)
• if you're using hbm2ddl then the CACHE value on the sequence is not set

Usage

You can use this sequence generator like this

@Id
@GenericGenerator(
        name = "some_column_name_id_generator",
        strategy = "com.github.marschall.hibernate.batchsequencegenerator.BatchSequenceGenerator",
        parameters = {
            @Parameter(name = "sequence", value = "SOME_SEQUENCE_NAME"),
            @Parameter(name = "fetch_size", value = "SOME_FETCH_SIZE_VALUE")
        })
@GeneratedValue(generator = "some_column_name_id_generator")
@Column(name = "SOME_COLUMN_NAME")
private Long someColumnName;

You need to configure the following things

SOME_SEQUENCE_NAME

the SQL name of the sequence from which the values should be fetched

SOME_FETCH_SIZE_VALUE

integer, how many values should be fetched at once, this should be equal to the CACHE value of the sequence

SOME_COLUMN_NAME

the SQL name of the column for which the value should be generated

some_column_name_id_generator

unique if of the generator

Database Support

The following RDBMS have been verified to work

• DB2
• Firebird
• H2
• HSQLDB
• MariaDB 10.3 with Hibernate 5.2.17 or later
• Oracle
• Postgres
• SQL Sever
• In theory any RDBMS that supports WITH RECURSIVE and sequences is supported.

Unfortunately these RDBMS are currently not supported

• MySQL due to the lack of sequence support

DDL

For the best possible performance the CACHE value of the database sequence should be set to the same value as the "fetch_size" parameter.

Hibernate Versions

The project has been developed and tested against Hibernate 5.6.

Dependencies

The project has no dependencies other than Hibernate.

Further Reading

• https://vladmihalcea.com/hibernate-batch-sequence-generator/
• https://vladmihalcea.com/how-to-batch-insert-and-update-statements-with-hibernate/
• https://docs.jboss.org/hibernate/orm/5.0/manual/en-US/html/ch03.html#configuration-optional-properties
• https://vladmihalcea.com/hibernate-identity-sequence-and-table-sequence-generator/
• https://dzone.com/articles/how-batch-insert-and-update