Deep Dive: Salesforce’s Multi-Tenancy Architecture

🔹 Who is Involved?

• Provider: Salesforce (One of the world’s largest SaaS companies, built on a proprietary multi-tenant architecture).
• Clients (Tenants): Coca-Cola, Amazon, Toyota, Spotify, and thousands of other businesses using Salesforce CRM.

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1️⃣ Salesforce’s Multi-Tenancy Model: Shared Database, Shared Schema

🔍 How Salesforce Stores Data

Salesforce serves thousands of businesses from a single database instance but ensures strict tenant isolation using:

1. Tenant Identifiers (organization_id) – Uniquely identifies each company.
2. Metadata-Driven Architecture – Each customer’s configurations (fields, workflows) are stored as metadata instead of separate tables.
3. Row-Level Security (RLS) & Object-Level Security (OLS) – Ensures users can only access their company’s data.

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🔹 Example: How Customer Data is Stored in Salesforce

Shared Table with Tenant Identifier (organization_id)

CREATE TABLE contacts (
    id SERIAL PRIMARY KEY,
    organization_id INT NOT NULL,  -- Tenant Identifier
    name VARCHAR(255),
    email VARCHAR(255),
    created_at TIMESTAMP DEFAULT NOW()
);

Fetching Data for a Specific Tenant (Customer Organization)

SELECT * FROM contacts WHERE organization_id = 456;  -- Only fetch contacts for Org 456

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2️⃣ How Salesforce Handles Scaling for Millions of Tenants

🔹 Key Technologies Used

✅ Proprietary Multi-Tenant Database (Force.com Platform)

✅ Row-Level Security (RLS) – Ensures strict data isolation.

✅ Metadata-Driven Architecture – Instead of creating separate tables for each company, Salesforce stores configurations as metadata.

✅ Horizontal Partitioning (Sharding) – Distributes large customers across different servers.

🔹 Example: Metadata-Driven Multi-Tenancy

Instead of creating a custom_fields table per tenant, Salesforce stores custom fields dynamically in metadata:

{
    "organization_id": 456,
    "custom_field_name": "Customer_Type",
    "custom_field_value": "Premium"
}

This means each company can define its own custom fields, workflows, and reports without changing the core database structure.

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3️⃣ How Salesforce Ensures Data Isolation & Security

🔹 1. Row-Level Security (RLS)

Salesforce ensures that a tenant (company) can only access its own records:

CREATE POLICY tenant_isolation
ON contacts
FOR SELECT
USING (organization_id = current_setting('app.current_organization')::int);

Before queries run, Salesforce sets the current tenant:

SET app.current_organization = 456;
SELECT * FROM contacts;  -- Fetches only Org 456’s contacts

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🔹 2. Object-Level Security (OLS) & Field-Level Security (FLS)

Salesforce also restricts access to specific objects (tables) and fields based on user roles.

✅ Example: Role-Based Access

• Admins can view all customer records.
• Sales reps can only view their assigned customers.

SELECT * FROM contacts WHERE assigned_sales_rep = 'John Doe';

✅ Example: Hiding Sensitive Fields

• Field-level security ensures only authorized users can access sensitive data.

SELECT name, email FROM contacts;  -- Omits sensitive fields like `ssn`

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4️⃣ Why Salesforce Uses a Shared Schema Instead of Separate Databases

Approach	Isolation	Performance	Cost	Complexity
Shared Schema (Salesforce’s Model)	Medium	High	Low	Low
Separate Databases per Tenant	High	Medium	High	High

Salesforce’s Reasoning:

• ✅ Shared schema allows fast retrieval of multi-tenant data.
• ✅ Metadata-driven architecture makes customization easy.
• ✅ Security rules (RLS, OLS, FLS) ensure tenant isolation.
• ✅ Sharding helps distribute large customers across different database clusters.

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🔹 Final Takeaways

✔️ Salesforce uses a shared database with row-level security & metadata-driven multi-tenancy.

✔️ Customers customize their CRM setup without altering the database structure.

✔️ Sharding & indexing ensure scalability for large enterprises like Coca-Cola & Amazon.

🚀 This approach allows Salesforce to serve thousands of businesses while keeping their data secure and isolated.

Would you like a deep dive into another SaaS example like Shopify or QuickBooks? 😊