Explain advanced database sharding strategies and routing algorithms in PHP systems.

Database sharding splits large datasets across multiple nodes, requiring intelligent routing to ensure scalability and performance.

Sharding is used when a single database cannot handle scale.

Sharding strategies:

Consistent hashing distributes data evenly.

Data split by ranges (e.g., user_id).

Data partitioned by region.

Lookup service maps keys to shards.

Routing challenges:

Advanced techniques: