[DevoxxPL2022] Integrate Hibernate with Your Elasticsearch Database • Bartosz de Boulange
At Devoxx Poland 2022, Bartosz de Boulange, a Java developer at BGŻ BNP Paribas, Poland’s national development bank, delivered an insightful presentation on Hibernate Search, a powerful tool that seamlessly integrates traditional Object-Relational Mapping (ORM) with NoSQL databases like Elasticsearch. Bartosz’s talk focused on enabling full-text search capabilities within SQL-based applications, offering a practical solution for developers seeking to enhance search functionality without migrating entirely to a NoSQL ecosystem. Through a blend of theoretical insights and hands-on coding demonstrations, he illustrated how Hibernate Search can address complex search requirements in modern applications.
The Power of Full-Text Search
Bartosz began by addressing the challenge of implementing robust search functionality in applications backed by SQL databases. For instance, in a bookstore application, users might need to search for specific phrases within thousands of reviews. Traditional SQL queries, such as LIKE statements, are often inadequate for such tasks due to their limited ability to handle complex text analysis. Hibernate Search solves this by enabling full-text search, which includes character filtering, tokenization, and normalization. These features allow developers to remove irrelevant characters, break text into searchable tokens, and standardize data for efficient querying. Unlike native SQL full-text search capabilities, Hibernate Search offers a more streamlined and scalable approach, making it ideal for applications requiring sophisticated search features.
Integrating Hibernate with Elasticsearch
The core of Bartosz’s presentation was a step-by-step guide to integrating Hibernate Search with Elasticsearch. He outlined five key steps: creating JPA entities, adding Hibernate Search dependencies, annotating entities for indexing, configuring fields for NoSQL storage, and performing initial indexing. By annotating entities with @Indexed, developers can create indexes in Elasticsearch at application startup. Fields are annotated as @FullTextField for tokenization and search, @KeywordField for sorting, or @GenericField for basic querying. Bartosz emphasized the importance of the @FullTextField, which enables advanced search capabilities like fuzzy matching and phrase queries. His live coding demo showcased how to set up a Docker Compose file with MySQL and Elasticsearch, configure the application, and index a bookstore’s data, demonstrating the ease of integrating these technologies.
Scalability and Synchronization Challenges
A significant advantage of using Elasticsearch with Hibernate Search is its scalability. Unlike Apache Lucene, which is limited to a single node and suited for smaller projects, Elasticsearch supports distributed data across multiple nodes, making it ideal for enterprise applications. However, Bartosz highlighted a key challenge: synchronization between SQL and NoSQL databases. Changes in the SQL database may not immediately reflect in Elasticsearch due to communication overhead. To address this, he introduced an experimental outbox polling coordination strategy, which uses additional SQL tables to maintain update order. While still in development, this feature promises to improve data consistency, a critical aspect for production environments.
Practical Applications and Benefits
Bartosz demonstrated practical applications of Hibernate Search through a bookstore example, where users could search for books by title, description, or reviews. His demo showed how to query Elasticsearch for terms like “Hibernate” or “programming,” retrieving relevant results ranked by relevance. Additionally, Hibernate Search supports advanced features like sorting by distance for geolocation-based queries and projections for retrieving partial documents, reducing reliance on the SQL database for certain operations. These capabilities make Hibernate Search a versatile tool for developers aiming to enhance search performance while maintaining their existing SQL infrastructure.