Session-Level Batching (Hibernate 5.2 or Higher) in MySQL

Description: Batch inserts via Hibernate session-level batching (Hibernate 5.2 or higher) in MySQL.

Key points:

• in application.properties set spring.jpa.properties.hibernate.generate_statistics (just to check that batching is working)
• in application.properties set JDBC URL with rewriteBatchedStatements=true (optimization for MySQL)
• in application.properties set JDBC URL with cachePrepStmts=true (enable caching and is useful if you decide to set prepStmtCacheSize, prepStmtCacheSqlLimit, etc as well; without this setting the cache is disabled)
• in application.properties set JDBC URL with useServerPrepStmts=true (this way you switch to server-side prepared statements (may lead to signnificant performance boost))
• in case of using a parent-child relationship with cascade persist (e.g. one-to-many, many-to-many) then consider to set up spring.jpa.properties.hibernate.order_inserts=true to optimize the batching by ordering inserts
• in entity, use the assigned generator since MySQL IDENTITY will cause insert batching to be disabled
• the Hibernate Session is obtained by un-wrapping it via EntityManager#unwrap(Session.class)
• the batching size is set via Session#setJdbcBatchSize(Integer size) and get via Session#getJdbcBatchSize()
• in DAO, flush and clear the Persistence Context from time to time; this way you avoid to "overwhelm" the Persistence Context
• if is not needed, then ensure that Second Level Cache is disabled via spring.jpa.properties.hibernate.cache.use_second_level_cache=false

Output example:

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