Introduction

Features

A rare example of:

1. Wide-area Distributed Transactions

   Very desirable, but two-phase commit is too slow and prone to blocking

2. Wide-area Synchronous Replciation

   1. Two-phase commit over Paxos
   2. Synchronized time for fast Read-Only txns.

Motivation

Spanner is developed for Google F1, which previously implemented by sharded over many MySQL and BigTable DBs.

The business needs:

• Better replication ⇒ Synchronous
• More flexible sharding
• Cross-shard txns

The workload is dominated by RO txns.

And a strong consistency of External Consistency is required

Organization

Whole organization

Spanserver software stack

Why this arrangement?

• Sharding allow huge total throughput via parallelism