This error occurs when inserting data into a partitioned PostgreSQL table when no child partition exists for the data's values. With declarative partitioning, data is routed to child partitions based on constraints, and if a matching partition doesn't exist, PostgreSQL rejects the insert. Create missing partitions ahead of time or use automatic partition management to resolve this.
PostgreSQL declarative partitioning splits large tables into smaller, more manageable child partitions based on criteria like date ranges or value ranges. When you insert a row, PostgreSQL automatically routes it to the appropriate child partition. However, if no child partition exists with constraints matching the row's values, PostgreSQL cannot determine where to store the row and raises this error. This is a safety mechanism to prevent data from disappearing into the table structure. The error commonly occurs with time-based partitioning when you insert data for a future date before creating that date's partition.
Review the error message and your application logs to determine what data triggered the error. Look for the specific values (usually a date or range key) that couldn't find a matching partition. For example, if the error mentions a date in December 2025, that partition probably doesn't exist yet.
-- Check which partitions exist
SELECT schemaname, tablename
FROM pg_tables
WHERE tablename LIKE 'your_table_%'
ORDER BY tablename;Query the system catalog to understand how the table is currently partitioned:
-- Check partition constraints
SELECT
schemaname,
tablename,
pg_get_expr(relpartbound, oid) as partition_constraint
FROM pg_class
JOIN pg_tables ON pg_class.relname = pg_tables.tablename
WHERE pg_class.relispartition = true
AND pg_tables.tablename LIKE 'your_table_%';This shows the range or list constraints for each partition. Look for gaps or missing ranges that match your data.
Once you've identified the missing partition, create it with the appropriate constraint. The exact syntax depends on your partitioning type:
For RANGE partitioning (most common with dates):
CREATE TABLE your_table_2025_12
PARTITION OF your_table
FOR VALUES FROM ('2025-12-01') TO ('2026-01-01');For LIST partitioning:
CREATE TABLE your_table_region_us
PARTITION OF your_table
FOR VALUES IN ('US', 'CA', 'MX');Make sure the constraints match your data and don't overlap with existing partitions. The TO boundary is exclusive, so FROM ('2025-12-01') TO ('2026-01-01') includes all of December but not January 1st.
To prevent this error in the future, create a DEFAULT partition that catches any rows that don't match explicit partition constraints:
CREATE TABLE your_table_default
PARTITION OF your_table DEFAULT;Now, if you forget to create a partition, rows will be inserted into the default partition instead of failing. However, the default partition can grow large, so periodically review and migrate data from it to proper partitions:
-- Check how much data is in the default partition
SELECT COUNT(*) FROM your_table_default;To avoid this error long-term, automate partition creation using a scheduled job or trigger. Create a function that generates partitions ahead of time:
CREATE OR REPLACE FUNCTION create_monthly_partitions()
RETURNS void AS $$
DECLARE
partition_date DATE := DATE_TRUNC('month', CURRENT_DATE);
BEGIN
FOR i IN 0..3 LOOP -- Create 3 months ahead
EXECUTE format(
'CREATE TABLE IF NOT EXISTS your_table_%s PARTITION OF your_table FOR VALUES FROM (%L) TO (%L)',
TO_CHAR(partition_date + (i || ' months')::INTERVAL, 'YYYY_MM'),
partition_date + (i || ' months')::INTERVAL,
partition_date + ((i + 1) || ' months')::INTERVAL
);
END LOOP;
END;
$$ LANGUAGE plpgsql;
-- Schedule this function to run daily
SELECT cron.schedule('create_monthly_partitions', '0 2 * * *', 'SELECT create_monthly_partitions()');Note: This requires the pg_cron extension to be installed.
After creating the missing partition(s), retry the insert operation:
INSERT INTO your_table (column1, column2, date_column)
VALUES ('value1', 'value2', '2025-12-15');The insert should now succeed since the partition exists. If using an application, resubmit the failed request or resume the data pipeline.
TimescaleDB alternative: If you're working with time-series data and frequently encounter partition management issues, consider using TimescaleDB (an extension for PostgreSQL). TimescaleDB uses hypertables which automatically create partitions (called "chunks") transparently as new data arrives, eliminating the need for manual partition management entirely. To migrate: install the TimescaleDB extension, convert your table to a hypertable using SELECT create_hypertable('your_table', 'time_column'), and adjust your chunk intervals as needed. Partition naming conventions: Many teams use patterns like table_YYYY_MM for monthly partitions or table_YYYY_WW for weekly partitions. Document your chosen naming scheme to make partition management easier. Lock considerations: Creating a partition with CREATE TABLE ... PARTITION OF does require an AccessExclusiveLock on the parent table, which blocks other operations. For high-traffic tables, consider scheduling partition creation during maintenance windows.
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