Partitioning is a powerful technique in PostgreSQL for managing large datasets. It can significantly enhance query performance, data management, and scalability.

But which method should you choose: Native Partitioning or the older Inheritance + Trigger approach?

This article will analyze both techniques, compare their mechanisms, pros and cons, and practical applications to help you make an informed decision.

What is Partitioning and Why is it Important?

Partitioning is the process of dividing a large table into smaller, more manageable pieces called partitions. The benefits include:

• Faster queries due to reduced I/O.
• Simplified table management.
• Efficient storage or deletion of old data.

Think of partitioning as organizing a massive filing cabinet by month — it’s much easier to find and remove specific sections of data.

Historical Context in PostgreSQL

Partitioning in PostgreSQL has evolved over time:

How Each Method Works

🛠 Inheritance + Trigger

This older method uses table inheritance and triggers to route data.

CREATE TABLE logs (
    id serial,
    log_time timestamp NOT NULL,
    log_message text
);

CREATE TABLE logs_2024_01 () INHERITS (logs);
CREATE TABLE logs_2024_02 () INHERITS (logs);

CREATE FUNCTION logs_insert_trigger()
RETURNS TRIGGER AS $$
BEGIN
    IF (NEW.log_time >= '2024-01-01' AND NEW.log_time < '2024-02-01') THEN
        INSERT INTO logs_2024_01 VALUES (NEW.*);
    ELSIF (NEW.log_time >= '2024-02-01' AND NEW.log_time < '2024-03-01') THEN
        INSERT INTO logs_2024_02 VALUES (NEW.*);
    ELSE
        RAISE EXCEPTION 'Date out of range';
    END IF;
    RETURN NULL;
END;
$$ LANGUAGE plpgsql;

CREATE TRIGGER insert_logs_trigger
BEFORE INSERT ON logs
FOR EACH ROW EXECUTE FUNCTION logs_insert_trigger();

✅ Explanation:

• The logs table is abstract and does not store data directly.
• The trigger checks log_time and routes rows to the appropriate child table.

⚙ Native Partitioning (PostgreSQL ≥ 10)

Native Partitioning simplifies the setup using built-in features.

CREATE TABLE logs (
    id serial,
    log_time timestamp NOT NULL,
    log_message text
) PARTITION BY RANGE (log_time);

CREATE TABLE logs_2024_01 PARTITION OF logs
    FOR VALUES FROM ('2024-01-01') TO ('2024-02-01');

CREATE TABLE logs_2024_02 PARTITION OF logs
    FOR VALUES FROM ('2024-02-01') TO ('2024-03-01');

✅ Key Benefits:

• No need for triggers or manual routing logic.
• PostgreSQL automatically inserts into the correct partition.
• Query performance is optimized through pruning.

Pros and Cons Comparison

Performance

In most benchmarks:

• Insert Performance: Native is 20–50% faster.
• Query Performance: Native benefits from partition pruning, scanning only relevant partitions.

When to Use Each Method

✅ Use Native Partitioning when:

• You are using PostgreSQL 10 or later.
• You prioritize performance and simplicity.
• Your partitioning model fits range/list/hash.

✅ Use Inheritance + Trigger when:

• You are limited to PostgreSQL ≤ 9.6.
• You need custom insert logic not supported natively.

Migrating from Inheritance to Native

When migrating:

• Plan your schema transition carefully.
• Use native commands like ATTACH PARTITION and DETACH PARTITION.
• Check your constraints, indexes, and foreign keys.

Conclusion

Both partitioning methods have their value depending on the context:

• Native Partitioning is ideal for modern setups — faster, simpler, and better integrated.
• Inheritance + Trigger remains useful for legacy systems or when custom logic is required.