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MongoDB gets support for multi-document ACID transactions

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Re: MongoDB gets support for multi-document ACID transactions

#241

Post by pizza234 »

furicane wrote: post #44
pizza234 wrote: post #29

Earlier quoted context omitted.

> I often wondered why anyone would use MongoDB or similar, but I always keep forgetting that developers are usually inexperienced hipsters You can do a basic google search, and you will find out use cases where document-based data storages are advantageous compare to relational ones.

So what you're saying that if I find something on google, it's undoubtedly true and I should blindly believe it? For every one of those use cases, I can provide a counter-argument. And there are many more who can do the same.

When all you have is a hammer, everything looks like a nail.

Re: MongoDB gets support for multi-document ACID transactions

#242

Post by majidazimi »

ZenoArrow wrote: post #162
jasondc wrote: post #53

Earlier quoted context omitted.

Triggers?? Where you add some application logic to the database, 10 years go by, and no one has any idea how the triggers work? Or even how to test them? I've never seen triggers used successfully in any production application (maybe they work at first, but give them time, and a few code changes).

> "I've never seen triggers used successfully in any production application" Triggers have one or two good use cases, and plenty of bad use cases. I would suggest the strongest use case is for data validation. Databases don't have very sophisticated type systems, and custom data types can cause headaches. Database triggers allow you to ensure that the data stored in fields matches a set of criteria. To give a basic e…

We are using it for building aggregate tables from raw table. We insert data into raw table. And triggers propagate running Min/Max/Avg for hourly/daily/monthly tables. After couple of months we truncate our raw tables but keep aggregate tables. Duplicates are easily removed based on insert. And we get instantaneous result on our aggregate tables (No hourly batch job)

Re: MongoDB gets support for multi-document ACID transactions

#245

Post by alyson-cabral »

jbellis wrote: post #234
alyson-cabral wrote: post #19

I'm the Product Manager on the Core Server responsible for the multi-document transactions project. For those of you interested in learning more about how we're building transactions in MongoDB, I suggest checking out this video that discusses creating WiredTiger timestamps to enforce correctness in operation ordering across the storage layer. The description is presented by Dr. Michael Cahill, the co-founder of the…

Hi Alyson, Thanks for the link! It looks like the video covers using timestamps to implement replicated mvcc correctly from primary to other replicas. The interesting next step is how you go from there to multi-document across different primaries. Or is this limited to documents in a single shard?

In 4.0, transactions will just be across replica-sets. The following release will have transactions across the entire sharded cluster (across multiple primaries).
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