Tag: BatchInsert

All the articles with the tag "BatchInsert".

• Why saveAll() Becomes 10K INSERTs — IDENTITY and Hibernate's Structural Batch Disablement

  4 May, 2026

  hibernate.jdbc.batch_size=50 is set, yet saveAll() of 10,000 rows fires 10,000 INSERTs. GenerationType.IDENTITY needs LAST_INSERT_ID() per INSERT, which Statement.RETURN_GENERATED_KEYS cannot deliver in batch — Hibernate disables batching structurally. Application-managed IDs (TABLE strategy simulation) restore batching at ~200 SQL. Raw JDBC batchUpdate with rewriteBatchedStatements=true rewrites them as multi-value INSERT (~10 SQL) — the fastest path. The DZone "IDENTITY → SEQUENCE 100x" post is PostgreSQL-specific. MySQL has no native SEQUENCE (it falls back to TABLE), so the real options on MySQL are UUID, TableGenerator pooled-lo, Snowflake/TSID, or raw JDBC batch.