How to Choose PostgreSQL over Oracle

Why use PostgreSQL instead of Oracle?

PostgreSQL delivers enterprise-grade features comparable to Oracle while remaining open-source, license-free, and highly extensible.

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Description

Why pick PostgreSQL instead of Oracle?

PostgreSQL eliminates proprietary license fees, offers permissive open-source terms, and ships advanced SQL compliance, JSONB, window functions, and logical replication that rival Oracle features without recurring costs.

How big are the cost savings?

PostgreSQL is free to use in production. You avoid Oracles per-core licensing, support contracts, and audit risk, cutting total cost of ownership by 70–90% for most teams.

Is feature parity good enough for enterprise apps?

PostgreSQL supports full ACID transactions, MVCC, partitioning, parallel query, materialized views, and rich indexing (GIN, GiST, BRIN). These cover the majority of Oracle workloads.

What developer advantages does Postgres bring?

Native JSONB lets you mix relational and document data, PL/pgSQL feels similar to PL/SQL, and extensibility enables PostGIS, Timescale, and custom extensions without vendor lock-in.

How does migration work?

Tools like ora2pg, AWS SCT, and pgloader convert schemas, data, and PL/SQL to PL/pgSQL. Most sequences, triggers, and views translate automatically with minor syntax adjustments.

Can PostgreSQL scale like Oracle RAC?

Horizontal read scaling uses streaming replication, while logical replication and sharding frameworks (Citus, pg_shard) distribute writes. Many SaaS platforms handle billions of rows on Postgres.

Best practices for switching

Prototype critical queries, benchmark with realistic data, and enable extensions (pg_stat_statements) to monitor performance. Use identity columns instead of Oracle sequences for simpler inserts.

Common mistakes to avoid

Under-estimating PL/SQL to PL/pgSQL differences and ignoring free vacuum/autovacuum tuning can delay go-live. Address them early for smooth adoption.

Why How to Choose PostgreSQL over Oracle is important

How to Choose PostgreSQL over Oracle Example Usage


-- Identify high-value customers who spent >$5,000 last quarter
WITH quarterly_totals AS (
    SELECT  o.customer_id, SUM(o.total_amount) AS total
    FROM    Orders o
    WHERE   o.order_date BETWEEN date_trunc('quarter', CURRENT_DATE - INTERVAL '1 quarter')
                             AND date_trunc('quarter', CURRENT_DATE) - INTERVAL '1 day'
    GROUP BY o.customer_id
)
SELECT c.id, c.name, c.email, q.total
FROM   quarterly_totals q
JOIN   Customers c ON c.id = q.customer_id
WHERE  q.total > 5000
ORDER  BY q.total DESC;

How to Choose PostgreSQL over Oracle Syntax


-- PostgreSQL version
CREATE TABLE Orders (
    id            BIGSERIAL PRIMARY KEY,
    customer_id   BIGINT REFERENCES Customers(id),
    order_date    DATE DEFAULT CURRENT_DATE,
    total_amount  NUMERIC(12,2),
    metadata      JSONB,               -- not available natively in Oracle
    created_at    TIMESTAMPTZ DEFAULT NOW()
);

-- Identity columns (Postgres 10+ vs Oracle SEQUENCE + TRIGGER)
CREATE TABLE Products (
    id     BIGINT GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
    name   TEXT NOT NULL,
    price  NUMERIC(10,2),
    stock  INT
);

-- Upsert (MERGE substitute)
INSERT INTO Products (name, price, stock)
VALUES ('Widget', 9.99, 100)
ON CONFLICT (name) DO UPDATE SET stock = Products.stock + EXCLUDED.stock;

-- JSONB filter (no Oracle equivalent without extensions)
SELECT id, metadata->>'shippingAddress' AS ship_to
FROM Orders
WHERE metadata->>'status' = 'shipped';

Common Mistakes

Ignoring PL/SQL to PL/pgSQL differences—package variables, autonomous transactions, and exception handling need refactoring. Use ora2pg reports and adjust code before cut-over.
Treating autovacuum as set-and-forget. High-write workloads need tuned autovacuum thresholds; otherwise, table bloat hurts performance. Monitor pg_stat_user_tables and adjust autovacuum_vacuum_scale_factor.

Frequently Asked Questions (FAQs)

Does PostgreSQL support stored procedures like Oracle?

Yes. PL/pgSQL provides procedures, functions, triggers, and exception blocks. From Postgres 11 onward, CALL executes stored procedures with transaction control.

How are Oracle sequences handled?

PostgreSQL offers both classic SEQUENCE objects and identity columns (GENERATED AS IDENTITY) that embed sequence semantics directly in the table definition.

Can I get commercial support for PostgreSQL?

Absolutely. Companies such as EDB, Percona, and AWS provide enterprise support, 24/7 SLAs, and migration services comparable to Oracle Premier Support.