Statistics is not enabled: Hibernate Statistics API access error

Question

Statistics is not enabled
The Hibernate ORM throws a org.hibernate.HibernateException with the message "Statistics is not enabled" when SessionFactory.getStatistics() is called while statistics collection is not explicitly activated. This behavior is documented in the Hibernate 5.x and 6.x APIs and is triggered only by accessing the statistics API, not by other runtime operations.
In practice, developers enable statistics by setting hibernate.generate_statistics=true in the configuration or by calling setStatisticsEnabled(true) programmatically. The trade‑off is clear: enabling statistics incurs additional overhead, which may be undesirable in high‑throughput production environments, whereas disabling it protects performance but prevents detailed diagnostic data.
Despite these known trade‑offs, the community has not reached consensus on whether statistics should be enabled by default. The unresolved decision remains: should Hibernate provide a sensible default that balances diagnostic value against performance cost, or should it continue to require explicit activation to avoid accidental overhead?
What factors should influence the default statistics setting across different deployment contexts?  How can developers reliably determine whether statistics are currently enabled without triggering the exception?  Should Hibernate expose a programmatic query to report the current statistics state?

Tasadduq Burney · Answer

Direct answer
The HibernateException: Statistics is not enabled is thrown by SessionFactory.getStatistics() when statistics collection has not been explicitly activated. To check the state safely, call SessionFactory.isStatisticsEnabled(); it returns a boolean and does not throw. To use the Statistics API, enable collection first with hibernate.generate_statistics=true in your configuration or by calling the programmatic setStatisticsEnabled(true) during bootstrap. Hibernate already exposes the programmatic query you are asking for—isStatisticsEnabled()—so a separate status API would be redundant.

Likely explanation vs. documented behavior
The exception is a guard, not a bug. The documented behavior in Hibernate 5.x and 6.x is that getStatistics() refuses to return a live Statistics instance when collection is off, preventing accidental overhead or misleading reads. The unresolved design question—whether the default should flip to enabled—is separate from that runtime contract.

Factors that should influence the default

Environment: development and test environments usually benefit from diagnostics; production often prioritizes throughput.
Performance sensitivity: high-throughput or memory-constrained deployments should keep statistics off unless monitoring demands them.
Observability requirements: if external tooling or audit rules depend on Hibernate counters, enabling may be mandatory.
Lifecycle cost: statistics retain historical counters; long-running processes must clear them or watch memory growth.

Reliable detection without the exception

Inspect your configuration for hibernate.generate_statistics. If it is absent or false, assume disabled.
In application code, call sessionFactory.isStatisticsEnabled() and log or assert the result.
If JMX is enabled, read the Statistics MBean’s enabled flag rather than invoking getStatistics() directly.

Practical verification
Before deploying, confirm the effective state in each environment. A quick assertion in your test suite can catch accidental enablement in production or accidental disablement in development:
assert sessionFactory.isStatisticsEnabled() == expectedValue;
If the assertion fails, adjust the configuration property or bootstrap code accordingly. Do not rely on catching the exception as a control-flow mechanism.

Statistics is not enabled: Hibernate Statistics API access error

Statistics is not enabled

1 answer

Direct answer

Likely explanation vs. documented behavior

Factors that should influence the default

Reliable detection without the exception

Practical verification

Your perspective belongs here.

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