Call Me Maybe: MongoDB Stale Reads
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Call Me Maybe: MongoDB Stale Reads
1–10 of 150 posts
Re: Call Me Maybe: MongoDB Stale Reads
#2Another instance of Kyle's amazing research! You may want to catch him on stage with other great minds at dotScale on June 8: http://dotscale.io
Re: Call Me Maybe: MongoDB Stale Reads
#3I'm so glad to see the Jepsen series re-instated. Thank you so much Stripe
Re: Call Me Maybe: MongoDB Stale Reads
#4If you are a database author and you get a bug report from Kyle, spend a long time thinking about it before closing the issue as invalid.
Re: Call Me Maybe: MongoDB Stale Reads
#5upvoted for the Look Around You link alone.
Re: Call Me Maybe: MongoDB Stale Reads
#6Shame this wasn't done with the latest version 3.0. Although given that improvements are scheduled for 3.1 I would imagine it might be still an issue.
Nice writeup either way though. Would like to see a similar article for Couch* and MySQL.
Re: Call Me Maybe: MongoDB Stale Reads
#7The most interesting lessons from the Jepsen series:
* You should never trust, and always verify, the claims made by database manufacturers.
* Especially when those claims relate to data integrity.
* Super-especially when every safety level provided by the manufacturer that includes the word "SAFE" is actually unsafe.
Re: Call Me Maybe: MongoDB Stale Reads
#8[deleted]
Re: Call Me Maybe: MongoDB Stale Reads
#9The most interesting lessons from the Jepsen series: * You should never trust, and always verify, the claims made by database manufacturers. * Especially when those claims relate to data integrity. * Super-especially when every safety level provided by the manufacturer that includes the word "SAFE" is actually unsafe.
Actually the broader lesson would be to assume the worst in your application layer and try and remediate/verify wherever possible.
If you look at his articles: Redis, PostgreSQL, Cassandra, ElasticSearch etc all had data consistency errors. And none of those have vendors making any claims.
It's pretty sobering to say the least.
Re: Call Me Maybe: MongoDB Stale Reads
#10There's a lot going on here, but the summary is: "What Mongo actually does is allow stale reads: it is possible to execute a WriteConcern=MAJORITY write of a new value, wait for it to return successfully, perform a read with ReadPreference=PRIMARY, and not see the value you just wrote."
https://jira.mongodb.org/browse/SERVER-17975?focusedCommentI...