Session JDBC — Overview & Setup¶

spring-ai-session-jdbc provides a JDBC-backed implementation of SessionRepository that stores session data in two relational tables. It supports PostgreSQL, MySQL, MariaDB, and H2 out of the box.

Tables¶

AI_SESSION          — session metadata (id, user_id, TTL, metadata JSON, event_version)
AI_SESSION_EVENT    — append-only event log (FK → AI_SESSION, ON DELETE CASCADE)

AI_SESSION_EVENT rows are ordered by a monotonic seq column (insertion order) and carry synthetic and archived flags. Compaction archives events in place rather than deleting them, so the full history stays searchable. The event_version column on AI_SESSION is incremented on every appendEvent and compactEvents call, enabling optimistic-lock compaction.

Dependency¶

<dependency>
    <groupId>org.springaicommunity</groupId>
    <artifactId>spring-ai-session-jdbc</artifactId>
    <version>${spring-ai-session.version}</version>
</dependency>

Schema¶

DDL scripts are bundled on the classpath. Run the one matching your database:

Database	Script
PostgreSQL	`org/springframework/ai/session/jdbc/schema-postgresql.sql`
H2	`org/springframework/ai/session/jdbc/schema-h2.sql`
MySQL / MariaDB	`org/springframework/ai/session/jdbc/schema-mysql.sql`

Apply the schema with Spring Boot's SQL initialisation:

spring:
  sql:
    init:
      schema-locations: classpath:org/springframework/ai/session/jdbc/schema-postgresql.sql

Or use your existing migration tool (Flyway, Liquibase) by copying the appropriate script into your migration directory.

Manual bean setup¶

@Bean
SessionRepository sessionRepository(DataSource dataSource) {
    return JdbcSessionRepository.builder()
        .dataSource(dataSource)   // SQL dialect is auto-detected from the DataSource URL
        .build();
}

@Bean
SessionService sessionService(SessionRepository sessionRepository) {
    return DefaultSessionService.builder().sessionRepository(sessionRepository).build();
}

The builder accepts optional overrides:

JdbcSessionRepository.builder()
    .dataSource(dataSource)
    .dialect(new PostgresJdbcSessionRepositoryDialect())  // explicit dialect
    .transactionManager(txManager)                        // custom tx manager
    .jsonMapper(customJsonMapper)                         // custom JSON serialization
    .build();

Using the repository¶

@Autowired SessionRepository sessions;

// Create a session
Session session = sessions.save(Session.builder()
    .id(UUID.randomUUID().toString())
    .userId("alice")
    .build());

// Append a message event
sessions.appendEvent(SessionEvent.builder()
    .id(UUID.randomUUID().toString())
    .sessionId(session.id())
    .timestamp(Instant.now())
    .message(new UserMessage("Hello"))
    .build());

// Query events
List<SessionEvent> events = sessions.findEvents(session.id(), EventFilter.builder().build());

Supported databases¶

Database	Dialect class
PostgreSQL	`PostgresJdbcSessionRepositoryDialect`
H2	`H2JdbcSessionRepositoryDialect`
MySQL / MariaDB	`MysqlJdbcSessionRepositoryDialect`

Other databases default to the PostgreSQL dialect. Open an issue or contribute a dialect implementation for additional databases.

Design notes¶

Message serialisation — each SessionEvent's wrapped Message is stored in three columns: message_type (enum name), message_content (plain text), and message_data (JSON for tool calls and tool responses). This avoids Jackson polymorphism on Spring AI message types.

Optimistic concurrency — the event_version column on AI_SESSION is incremented on every appendEvent and compactEvents call. compactEvents atomically claims the version slot with UPDATE … WHERE event_version = ? before modifying the event log, making compaction safe under concurrent access.

synthetic column — stored as a dedicated BOOLEAN column (not only in the metadata JSON blob) so EventFilter.excludeSynthetic() translates to a SQL predicate instead of an in-process scan.