50 Tips and Tricks for MongoDB Developers by Chodorow, Kristina -- Read -- Imperial Library of Trantor

Index

50 Tips and Tricks for MongoDB Developers SPECIAL OFFER: Upgrade this ebook with O’Reilly Preface

Who This Book Is For Conventions Used in This Book Using Code Examples Safari® Books Online How to Contact Us

1. Application Design Tips

Tip #1: Duplicate data for speed, reference data for integrity

Example: a shopping cart order Decision factors

Tip #2: Normalize if you need to future-proof data Tip #3: Try to fetch data in a single query

Example: a blog Example: an image board

Tip #4: Embed dependent fields Tip #5: Embed “point-in-time” data Tip #6: Do not embed fields that have unbound growth Tip #7: Pre-populate anything you can Tip #8: Preallocate space, whenever possible Tip #9: Store embedded information in arrays for anonymous access Tip #10: Design documents to be self-sufficient Tip #11: Prefer $-operators to JavaScript

Behind the scenes Getting better performance

Tip #12: Compute aggregations as you go Tip #13: Write code to handle data integrity issues

2. Implementation Tips

Tip #14: Use the correct types Tip #15: Override _id when you have your own simple, unique id Tip #16: Avoid using a document for _id Tip #17: Do not use database references Tip #18: Don’t use GridFS for small binary data Tip #19: Handle “seamless” failover Tip #20: Handle replica set failure and failover

3. Optimization Tips

Tip #21: Minimize disk access

Fuzzy Math

Tip #22: Use indexes to do more with less memory Tip #23: Don’t always use an index

Write speed

4. Data Safety and Consistency

Tip #29: Write to the journal for single server, replicas for multiserver Tip #30: Always use replication, journaling, or both Tip #31: Do not depend on repair to recover data Tip #32: Understand getlasterror Tip #33: Always use safe writes in development Tip #34: Use w with replication Tip #35: Always use wtimeout with w Tip #36: Don’t use fsync on every write Tip #37: Start up normally after a crash Tip #38: Take instant-in-time backups of durable servers

5. Administration Tips

Tip #39: Manually clean up your chunks collections Tip #40: Compact databases with repair Tip #41: Don’t change the number of votes for members of a replica set Tip #42: Replica sets can be reconfigured without a master up Tip #43: --shardsvr and --configsvr aren’t required Tip #44: Only use --notablescan in development Tip #45: Learn some JavaScript Tip #46: Manage all of your servers and databases from one shell Tip #47: Get “help” for any function Tip #48: Create startup files Tip #49: Add your own functions

Loading JavaScript from files

Tip #50: Use a single connection to read your own writes

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