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Databases at Scale: System Design: Uncharted

Courses System DesignDatabases at Scale

Databases at ScalePro

Scale reads with replicas, writes with careful partitions, and choose data models by access path.

System Design
Unit 4 of 12
20 lessons
151 min
420 XP

This unit is part of Pro. Upgrade to open every lesson in it.

Lessons

20 total

1The Filing RoomExplain how an index replaces a full-table scan with a keyed route to the matching record.ProInteractiveConcept7 min20 XPOpen
2Indexes, in One LessonWeigh faster keyed reads against the storage and maintenance every additional index adds to writes.ProInteractiveConcept7 min20 XPOpen
3Reads Are Easy, Writes Are HardExplain why replicas can share reads while writes still require ordering, constraints, and convergence.ProInteractiveConcept7 min20 XPOpen
4Leader and FollowersDesign a leader-follower topology that sends writes to one authority and reads to replicated copies.ProDiagramConcept10 min20 XPOpen
5The Vanishing PostRecognize replication lag as the cause of a recent successful write disappearing on an immediate replica read.ProInteractiveConcept7 min20 XPOpen
6Read Your Own WritesProvide read-your-own-writes by routing an author to a source known to contain their accepted write.ProInteractiveConcept7 min20 XPOpen
7Failover DrillSequence detection, replica selection, promotion, and writer redirection without creating two leaders.ProInteractiveConcept7 min20 XPOpen
8Split the ShelvesTrace how a shard key routes one record while queries without that key may fan out across partitions.ProInteractiveConcept7 min20 XPOpen
9Pick the Shard KeySelect a stable shard key that appears in common access paths and distributes traffic without obvious hotspots.ProInteractiveConcept7 min20 XPOpen
10The Celebrity RowIdentify hot-key skew even when the wider shard-key distribution is otherwise balanced.ProInteractiveConcept7 min20 XPOpen
11Resharding HurtsExplain why changing a live shard map requires moving and rerouting data while requests continue.ProInteractiveConcept7 min20 XPOpen
12Cross-Shard CostsPredict which joins, counts, and transactions become distributed coordination problems after sharding.ProInteractiveConcept7 min20 XPOpen
13Shard the BakeryLay out global catalog data and customer-partitioned orders with a replica for each durable leader.ProDiagramProject10 min20 XPOpen
14Families of StoresMatch relational, document, key-value, and wide-column models to the access patterns they favor.ProInteractiveConcept7 min20 XPOpen
15Copies on PurposeExplain how denormalization simplifies a hot read by accepting copy-update work or a defined stale window.ProInteractiveConcept7 min20 XPOpen
16Napkin: Storage GrowthEstimate retained storage from daily row growth, row size, and retention duration using decimal units.ProInteractiveConcept7 min20 XPOpen
17Read the Lag ChartLocate both a replica-lag breach and the later point where the replica has actually recovered.ProInteractiveConcept8 min20 XPOpen
18The One-Big-Database DreamDefend keeping one replicated database until measured limits justify the permanent complexity of splitting it.ProInteractiveConcept7 min20 XPOpen
19Explain ReplicationExplain how leader-follower copying adds read capacity and a failover candidate while permitting stale reads.ProInteractiveConcept8 min20 XPOpen
20Databases at Scale Mastery CheckCombine authoritative writes, replica reads, and partitioned order data into explicit read and write paths.ProDiagramMastery check10 min40 XPOpen

Caching Consistency