BEGIN:VCALENDAR VERSION:2.0 PRODID:-//HasGeek//NONSGML Funnel//EN DESCRIPTION:Design MVCC databases with real-world consistency guarantees X-WR-CALDESC:Design MVCC databases with real-world consistency guarantees NAME:Building a distributed transactional database X-WR-CALNAME:Building a distributed transactional database REFRESH-INTERVAL;VALUE=DURATION:PT12H SUMMARY:Building a distributed transactional database TIMEZONE-ID:Asia/Kolkata X-PUBLISHED-TTL:PT12H X-WR-TIMEZONE:Asia/Kolkata BEGIN:VEVENT SUMMARY:Building a distributed transactional database DTSTART:20260509T041500Z DTEND:20260509T120000Z DTSTAMP:20260419T102455Z UID:session/D51MxpodyjpEC7e5KXqVvq@hasgeek.com SEQUENCE:5 CREATED:20260413T053739Z DESCRIPTION:# 🧱 Workshop: Building a Distributed Transactional Database \n\n## 🎯 Target Audience\n* Senior engineers with a background in distr ibuted systems\, transactions\, and concurrency control\n* Enthusiasts who want to understand how transactions work in distributed databases\n\n---\ n\n## πŸ“˜ Workshop overview\nThis workshop explores the design space of g lobally consistent transactional databases by incrementally building a dis tributed **Multi-Version Concurrency Control (MVCC)** key-value store usin g **Hybrid Logical Clocks (HLC)**.\n\nParticipants will implement **Snapsh ot Isolation (SI)** and examine how **strongly consistent reads** can be a chieved under bounded clock skew without hardware-assisted time like TrueT ime\, using uncertainty detection and restart techniques.\n\nThe workshop emphasizes:\n* Correctness invariants\n* Timestamp ordering\n* Trade-offs between commit-wait and retry-based designs\n\nIt provides a unified conce ptual framework for understanding systems such as **Google Spanner\, Cockr oachDB\, and YugabyteDB**. \n\n---\n\n## βœ… Learning outcomes\nBy the end of the workshop\, participants will be able to:\n\n* Reason about time\, ordering\, and causality in distributed databases\n* Implement Hybrid Logi cal Clocks\n* Build an MVCC storage engine on top of a RocksDB-like store\ n* Implement Snapshot Isolation\n* Achieve linearizable reads under bounde d clock skew\n* Understand the limits of clock-based approaches\n\n---\n\n ## πŸ“‹ Prerequisites\n* Java 21+\n* Basic understanding of distributed sy stems\n\n---\n\n## πŸ”— Resources\n* **Repository:** [https://github.com/u nmeshjoshi/hybridclocktxn](https://github.com/unmeshjoshi/hybridclocktxn)\ n* **Framework:** Tickloom – [https://github.com/unmeshjoshi/tickloom](h ttps://github.com/unmeshjoshi/tickloom)\n *(Used for determinism and simu lation testing)*\n\n---\n\n# 🧩 Workshop Modules\n## Module 1: Time and Order in Distributed Systems (60 minutes)\n\n### 🎯 Objective\nUnderstan d why physical clocks fail and implement Hybrid Logical Clocks.\n\n### πŸ“š Concepts\n* Physical clock drift and NTP limitations\n* Logical clock s (Lamport) and causality\n* Hybrid Logical Clocks (HLC): combining physic al time with logical ticks\n\n### πŸ’» Coding Tasks\n\n#### 1. Implement ` HybridTimestamp`\nValue object holding:\n* `wallClockTime`\n* `logicalTick s`\n* Comparison logic\n\n#### 2. Implement `HybridClock`\n* `now()`\n* Ha ndling physical time updates\n* Handling same-millisecond logical ticks\n* `tick(remoteTime)` (Lamport rule)\n* MAX_OFFSET sanity checks\n\n### πŸ“ Artifacts\n* `src/main/java/org/example/txn/HybridTimestamp.java`\n* `src /main/java/org/example/txn/HybridClock.java`\n\n---\n\n## Module 2: The St orage Layer with RocksDB (60 minutes)\n### 🎯 Objective\nBuild a version ed key-value store using RocksDB.\n\n### πŸ“š Concepts\n* LSM Trees and Ro cksDB basics\n* MVCC mapping\n* Key design: `UserKey + Timestamp (descendi ng) β†’ Value`\n* Why descending timestamps enable efficient latest-versio n seeks\n* Iterators\, scan\, reverseScan\n\n### πŸ’» Coding Tasks\n\n#### 1. Implement `MVCCStore`\n* `put(key\, timestamp\, value)`\n β†’ `rocksD B.put(serialize(key\, timestamp)\, value)`\n\n* `get(key\, readTimestamp)` \n β†’ `rocksDB.seek(serialize(key\, readTimestamp))`\n\n**Challenge:** e fficient memcomparable key encoding.\n\n#### 2. Refactor\nReplace `Concurr entSkipListMap` with `RocksDBManager`.\n\n### πŸ“ Artifacts\n* `src/main/ java/org/example/txn/MVCCStore.java`\n* `src/main/java/org/example/txn/Roc ksDBStorage.java`\n\n---\n\n## Module 3: Transactions and Snapshot Isolati on (60 minutes)\n### 🎯 Objective\nImplement transaction lifecycle and S napshot Isolation.\n\n### πŸ“š Concepts\n* Snapshot reads at `T_start`\n* Write intents and buffering\n* Transaction states: Running\, Committed\, A borted\n* Atomic commit and visibility\n\n### πŸ’» Coding Tasks\n\n#### Re ad Path\n* Read at `T_read`\n* Resolve intents:\n\n * If intent is mine β†’ read\n * If intent is other:\n * Committed < `T_read` β†’ visible\ n * Committed > `T_read` β†’ ignore\n * Aborted / Pending β†’ ignore \n\n#### Write Path\n* Write intent with TxnId\n* Detect write–write con flicts\n* Check committed versions newer than `T_start`\n\n#### Commit Pat h\n* `commit(txnId)`\n* Mark COMMITTED with `T_commit`\n* Apply intents as ynchronously\n\n### πŸ“ Artifacts\n* `TxnClient.java`\n* `TransactionReco rd.java`\n\n---\n\n## Module 4: Distributed Consistency β€” Clock-Bound Wa it (60 minutes)\n\n### 🎯 Objective\nAchieve external consistency using HLC.\n\n### πŸ“š Concepts\n* Clock skew & uncertainty window\n\n```\nT_now ∈ [T_now - Ξ΅\, T_now + Ξ΅]\n```\n\n* Why causal transactions may appea r in the future\n* Commit-wait vs restart strategies\n\n### πŸ’» Coding Ta sks\n1. Simulate uncertainty (`MAX_CLOCK_SKEW`)\n2. Detect commits in unce rtainty window\n\n```\nT_commit ∈ [T_read - Ξ΅\, T_read]\n```\n\n3. Trig ger read restart with `T_restart = T_commit + Ξ΅`\n4. Client retry logic\n \n### πŸ“ Artifacts\n* `StorageReplica.java` (handleRead updates)\n* `Txn Client.java` (retry logic)\n\n---\n\n## Module 5: Putting It All Together (30 minutes)\n\n### 🎯 Objective\nRun end-to-end simulations.\n\n### β–Ά Tasks\n* Run `StorageReplicaCommitTest` (Snapshot Isolation)\n* Run `Cloc kBoundWaitTest` (External Consistency)\n\n### About the instructor - Unmes h Joshi\n**Unmesh Joshi** is a Distinguished Engineer at Thoughtworks. He is a software architecture enthusiast\, who believes that understanding pr inciples of distributed systems is as essential today as understanding web architecture or object-oriented programming was in the last decade. For t he last two years he has been publishing patterns of distributed systems o n martinfowler.com. \n**In 2023\, he authored the [book Patterns of Distri buted Systems](https://www.amazon.com/Patterns-Distributed-Systems-Addison -wesley-Signature/dp/0138221987) published by Addison Wesley Professional. ** This book is an essential catalog of patterns aimed at enhancing compre hension\, communication and education on distributed system design\nHe has also conducted various training sessions around this topic. Twitter: [@un meshjoshi](https://x.com/unmeshjoshi)\n\n### How to attend this workshop\n This workshop will be held online (_via Zoom_)\, and is open for [Rootconf annual members](https://hasgeek.com/rootconf#memberships).\nThis workshop is open to 30 participants only. Seats will be available on first-come-fi rst-serve basis. 🎟️\n\n### Contact information ☎️\nFor inquiries about the workshop\, contact +91-7676332020 or write to info@hasgeek.com LAST-MODIFIED:20260413T054208Z LOCATION:Online - https://hasgeek.com/rootconf/building-distributed-transa ctional-database-online/ ORGANIZER;CN=Rootconf:MAILTO:no-reply@hasgeek.com URL:https://hasgeek.com/rootconf/building-distributed-transactional-databa se-online/ BEGIN:VALARM ACTION:display DESCRIPTION:Building a distributed transactional database in 5 minutes TRIGGER:-PT5M END:VALARM END:VEVENT END:VCALENDAR