Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
MongoDB Transaction Pattern
Search
Ian Yang
May 20, 2013
Technology
0
390
MongoDB Transaction Pattern
Ian Yang
May 20, 2013
Tweet
Share
More Decks by Ian Yang
See All by Ian Yang
Migrate to JRuby
doitian
4
760
Tmux Cheatsheet
doitian
2
300
Javascript Test Frameworks
doitian
1
130
Backbone Intro
doitian
1
230
A Tour of Go
doitian
4
870
Other Decks in Technology
See All in Technology
本が全く読めなかった過去の自分へ
genshun9
0
900
B2C&B2B&社内向けサービスを抱える開発組織におけるサービス価値を最大化するイニシアチブ管理
belongadmin
1
6.1k
AWS認定を取る中で感じたこと
siromi
1
170
What’s new in Android development tools
yanzm
0
220
生成AI活用の組織格差を解消する 〜ビジネス職のCursor導入が開発効率に与えた好循環〜 / Closing the Organizational Gap in AI Adoption
upamune
7
5.1k
20250707-AI活用の個人差を埋めるチームづくり
shnjtk
4
3.6k
KubeCon + CloudNativeCon Japan 2025 に行ってきた! & containerd の新機能紹介
honahuku
0
120
CursorによるPMO業務の代替 / Automating PMO Tasks with Cursor
motoyoshi_kakaku
2
930
開発生産性を測る前にやるべきこと - 組織改善の実践 / Before Measuring Dev Productivity
kaonavi
3
1.1k
生成AI開発案件におけるClineの業務活用事例とTips
shinya337
0
240
Claude Code に プロジェクト管理やらせたみた
unson
4
2.3k
Oracle Database@Google Cloud:サービス概要のご紹介
oracle4engineer
PRO
0
100
Featured
See All Featured
KATA
mclloyd
30
14k
Building Adaptive Systems
keathley
43
2.7k
I Don’t Have Time: Getting Over the Fear to Launch Your Podcast
jcasabona
32
2.4k
Git: the NoSQL Database
bkeepers
PRO
430
65k
Let's Do A Bunch of Simple Stuff to Make Websites Faster
chriscoyier
507
140k
It's Worth the Effort
3n
185
28k
Sharpening the Axe: The Primacy of Toolmaking
bcantrill
44
2.4k
Easily Structure & Communicate Ideas using Wireframe
afnizarnur
194
16k
BBQ
matthewcrist
89
9.7k
Optimising Largest Contentful Paint
csswizardry
37
3.3k
Build The Right Thing And Hit Your Dates
maggiecrowley
36
2.8k
Optimizing for Happiness
mojombo
379
70k
Transcript
MongoDB Transaction Pattern Who? Ian Yang From? Intridea Inc. When?
2013-05-15 Wed
Outline 1 Overview 2 Write Operation Properties 3 Two Phrase
Commit 4 Recovering 5 Rollback 6 Multiple Applications 7 References
Transaction (ACID) Atomicity all or nothing. Consistency does not violate
any integrity constraints Isolation allow concurrent execution of transactions Durability Transaction is persistent after commit
MongoDB Features Atomicity Only on the level of a single
document. Write Concern Return write operation result
MongoDB Transaction Atomicity done or rollback Consistency rollback may leave
system in inconsistent state. Isolation other transactions can see intermediate result. Durability write concern, replica set, journal.
Requirements of Write Operations in Transaction Revertible for recover and
rollback Idempotent for resume, recover and rollback
Not Revertible db.users.save(user); db.users.update ({ username: "ian"}, user); db.users.update ({
username: "ian"}, {$set: {balance: 120}});
Revertible db.users.update ({ username: "ian"}, {$inc: {balance: 20}}); db.users.update ({
username: "ian"}, {$inc: {balance: -20}}); db.users.update ({ username: "ian"}, {$push: {tx: 20}}); db.users.update ({ username: "ian"}, {$pull: {tx: 20}});
Not Idempotent db.users.update ({ username: "ian"}, {$inc: {balance: 20}}); db.users.update
({ username: "ian"}, {$push: {tx: 20}}); db.users.update( {username: "ian", balance: 100}, {$inc: {balance: 20}} );
Idempotent db.users.update( {username: "ian", tx: {$ne: tx._id}}, {$inc: {balance: 20},
$push: {tx: tx._id}} ); db.users.update( {username: "ian", tx: tx._id}, {$inc: {balance: -20}, $pull: {tx: tx._id}} );
Sample Transfer 20 dollars from Ian to Daniel
Create Transaction Transaction provides a unique identifier, enough information to
recover and rollback, a document for atomic write operation.
var tx = { _id: ObjectId (), source: ian._id ,
dest: daniel._id , amount: 20 }; db.transactions.create(tx);
Transaction State Machine State represents transaction stages Different actions should
be taken in different stages to recover or rollback
Step 1: Create Transaction var tx = { _id: ObjectId
(), source: ian._id , dest: daniel._id , amount: 20, state: 'initial ' }; db.transactions.create(tx);
Step 2: initial → pending db.transactions.update( {_id: tx._id , state:
'initial '}, {$set: {state: 'pending '}} );
Step 3: Apply Transaction db.users.update( {_id: tx.source , tx: {$ne:
tx._id}}, {$push: {tx: tx._id}, $inc: { balance: - tx.amount }} ); db.users.update( {_id: tx.dest , tx: {$ne: tx._id}}, {$push: {tx: tx._id}, $inc: { balance: tx.amount }} );
Step 4: pending → committed db.transactions.update( {_id: tx._id , state:
'pending '}, {$set: {state: 'committed '}} );
Step 5: Remove Pending Transaction db.users.update( {_id: tx.source , tx:
tx._id}, {$pull: {tx: tx._id}} ); db.users.update( {_id: tx.dest , tx: tx._id}, {$pull: {tx: tx._id}} );
Step 6: committed → done db.transactions.update( {_id: tx._id , state:
'committed '}, {$set: {state: 'done'}} );
Recover Initial Transactions Recover from Step 2: initial → pending
Recover Pending Transactions Recover from Step 3: Apply Transactions
Recover Committed Transactions Recover from Step 5: Remove Pending Transaction
General Rule Recover from the Step just following the step
transaction just entered current state. State transition creates a check point
Rollback Operations Better to create a new transaction in reverse
direction for Committed Transactions and Done Transactions Use following steps to rollback initial and pending transactions
Rollback 1: state → canceling db.transactions.update( {_id: t._id , state:
{$in: ['initial ', ' pending ']}}, {$set: {state: 'canceling '}} );
Rollback 2: Undo the Transaction db.users.update( {_id: tx.dest , tx:
{$ne: tx._id}}, {$pull: {tx: tx._id}, $inc: { balance: - tx.amount }} ); db.users.update( {_id: tx.source , tx: tx._id}, {$pull: {tx: tx._id}, $inc: { balance: tx.amount }} );
Rollback 3: canceling → canceled db.transactions.update( {_id: t._id , state:
{$in: ['canceling ']}}, {$set: {state: 'canceled '}} );
Recover Rollback Restart from Rollback 2 for canceling transactions
Conclusion Create a document for any transaction Store transaction info
in the document Apply only Revertible and Idempotent operations
Conclusion (Cont.) Transit state to save current work Transit state
if several operation branches exists
Enough? Only 1 application can handle a give transaction at
any point in time.
Background A picks a pending transaction to recover B picks
also a pending transaction to recover
Scenario 1 A is so slow, when it starts apply
transaction, B already has done the transaction. A must rollback. If A exists abnormally, the transaction is in inconsistent state.
Scenario 2 B just finished Step 5: Removing Pending Transaction
A applied transactions and exited abnormally B change state to done without error
Solution findAndModify lock db.transactions.findAndModify ({ query: {state: "initial", application: {$exists:
0}}, update: {$set: {state: "pending", application: "A1"}}, new: true });
Lock Release db.transactions.findAndModify ({ query: {application: "A1"}, update: {$unset: {application:
1}}, new: true });
Lock Forever? Application exists abnormally before release the lock Solution:
timeout
Timeout Lock now = new Date(); timeout = new Date(now.valueOf
() + 60 * 10 * 1000); db.transactions.findAndModify ({ query: {state: "initial", lockUntil: {$not: {$gte: now}}}, update: {$set: {state: "pending", lockUntil: timeout}}, new: true });
Client Requirements Client timeout to ensure the operation is finished
in expected time. Check time after return from block IO Defer transactions cleanup
References http://docs.mongodb.org/ manual/tutorial/ perform-two-phase-commits/ http://docs.mongodb.org/ manual/tutorial/ isolate-sequence-of-operations/
Q & A