PostgreSQL raises fdw_too_many_handles (SQLSTATE HV014) when a foreign data wrapper session exceeds the maximum number of active statement handles.
fdw_too_many_handles occurs in PostgreSQL when a foreign table session opens more statement handles than the foreign data wrapper allows. Close idle cursors, increase the handle limit, or batch statements to resolve the error.
fdw_too_many_handles
PostgreSQL returns SQLSTATE HV014 with the condition name fdw_too_many_handles when a foreign data wrapper (FDW) connection opens more active statement handles than the wrapper or remote server allows. Each SELECT or cursor created on a foreign table counts as a handle.
The error stops the current query block and rolls back the transaction unless it is trapped by an exception handler.
Fixing it quickly prevents lost work and maintains FDW performance.
The error appears while running queries that hit foreign tables through postgres_fdw, mysql_fdw, or similar wrappers.
Long-lived sessions that iterate over many partitions or issue loops of dynamic SQL are the most common triggers.
Batch ETL jobs, analytical reports, and application pools that reuse connections can silently leak handles until the limit is reached, after which every new statement fails with fdw_too_many_handles.
Opening excessive cursors without closing them, running large loops of dynamic SQL on foreign tables, or setting a very low handle limit in the FDW or remote database can all push a session past the allowed threshold.
Network glitches that break cursor cleanup and bugs in driver versions that mismanage prepared statements occasionally create orphaned handles that count against the quota.
Close unused cursors with DEALLOCATE, COMMIT, or RELEASE SAVEPOINT to free statement handles.
Refactor code to reuse prepared statements instead of allocating new ones for each row. Increase the handle limit on the foreign server if possible.
When batch jobs require thousands of statements, split work into smaller transactions so that each commits and clears its handles before the next batch begins.
Long-running psql scripts often forget to DEALLOCATE prepared statements.
Add an explicit DEALLOCATE ALL at logical checkpoints to avoid fdw_too_many_handles.
ETL frameworks that open one cursor per partition should throttle concurrency or use cursor recycling. Switching to a set-based approach can remove the cursor explosion entirely.
Enable log_statement_stats in development to monitor handle usage. Review pg_prepared_statements on both local and foreign servers for leaks.
Always wrap foreign queries in try-finally blocks that close cursors.
Galaxy’s editor highlights long-lived cursors and suggests DEALLOCATE snippets, making it easy to fix leaks before code hits production.
fdw_dynamic_param_value_needed (HV002) arises when a parameter is missing during FDW execution. The fix usually involves binding the correct value.
fdw_invalid_handle (HV00B) indicates a stale or unknown handle. Closing and reopening the foreign connection resolves it.
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Each open cursor against a foreign table is a handle.
Sessions that create hundreds of cursors without closing them surpass the default limit.
A buggy FDW or client library may fail to close statements on COMMIT, leaving handles orphaned.
The foreign database might have a strict max_prepared_stmt_count or similar setting that is lower than expected.
Connection pools that multiplex many logical sessions onto one physical FDW connection inflate handle counts quickly.
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No. Any FDW that manages cursors, including mysql_fdw and oracle_fdw, can hit the handle limit.
Yes for most FDWs, but some wrappers delay cleanup. Use DEALLOCATE ALL for certainty.
Consult the FDW documentation or check the remote server setting, such as max_prepared_stmt_count in MySQL.
Galaxy flags long-lived cursors during code review and suggests closing them, reducing the chance of hitting the limit.
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