PostgreSQL Error - 0Z002 stacked_diagnostics_accessed_without_active_handler error explained

What is the stacked_diagnostics_accessed_without_active_handler error in PostgreSQL?

The error appears when a PL/pgSQL block calls GET STACKED DIAGNOSTICS without being inside an active EXCEPTION handler.

PostgreSQL only populates the stacked diagnostics area while handling a trapped exception. Accessing it at any other time triggers SQLSTATE 0Z002 and aborts the current function.

What Causes This Error?

Calling GET STACKED DIAGNOSTICS in the main body of a function, or in a BEGIN ...

END block that has no active exception context, immediately raises the error.

The error also fires when you attempt to inspect stacked diagnostics after you have already re-raised or cleared the exception, leaving no handler active.

How to Fix stacked_diagnostics_accessed_without_active_handler

Place the GET STACKED DIAGNOSTICS call inside the corresponding EXCEPTION clause so an error context is active.

When you only need general information, switch to GET DIAGNOSTICS, which is safe outside handlers and provides details on the most recent command.

Common Scenarios and Solutions

Logging exceptions: Wrap risky statements in a BEGIN … EXCEPTION block, then gather diagnostics inside the handler before re-raising.

Debugging: Replace rogue calls to GET STACKED DIAGNOSTICS with GET DIAGNOSTICS or conditional logic to run them only when SQLSTATE is not null.

Best Practices to Avoid This Error

Always pair GET STACKED DIAGNOSTICS with an EXCEPTION block in the same scope.

Use static code analysis or Galaxy’s inline linting to highlight misuse before deploying functions to production.

Related Errors and Solutions

raise_without_handler occurs when RAISE is executed where no exception is active.

Fix by ensuring a handler context exists or by using RETURN.

division_by_zero appears when dividing numeric types by zero. Prevent by validating inputs or trapping with EXCEPTION blocks.

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