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Amazon DynamoDB Transactions

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Re: Amazon DynamoDB Transactions

#71

Post by otterley »

wsh91 wrote: post #70
otterley wrote: post #62

Earlier quoted context omitted.

Spanner is not a non-relational database. As for Firestore, it’s not clear whether it supports cross-collection transactions. Cloud Datastore does not support cross-namespace transactions AFAICT.

a) Cloud Firestore supports transactions across the entire database. You can learn more about them here: https://cloud.google.com/firestore/docs/manage-data/transact... . b) Given that the primary use case for namespaces was/is multitenancy, it's not clear to me why you'd want to transact across them. Nevertheless, you can. What's leading you to draw this conclusion?

The documentation is what led me to that conclusion, since it's not explicit as to what the transaction boundaries are, but I could be mistaken. Does this mean that the poster's claim is erroneous?

Re: Amazon DynamoDB Transactions

#72

Post by Nican »

otterley wrote: post #23
ryanworl wrote: post #10

“DynamoDB is the only non-relational database that supports transactions across multiple partitions and tables.” Uh... this is just not true.

Can you identify some others?

CockroachDB And you can get pretty close to being schemlass with the json column, and maybe with the inverted index.

Re: Amazon DynamoDB Transactions

#73

Post by manigandham »

ngrilly wrote: post #53
manigandham wrote: post #48

Earlier quoted context omitted.

Many libraries handle db connections poorly, or have heavy-handled pooling systems, or aren't fully async, all of which limits total throughput. The key/value clients usually have a much simpler APIs like HTTP which scale much better.

I don't understand. What makes you think it's easier for NoSQL clients (versus SQL clients) to correctly implement connection pooling and async networking? For example, MongoDB and Cassandra wire protocols are not based on HTTP. And even if they were based on HTTP, connection pooling and async networking still requires a specific effort. Which libraries are you thinking of (as examples of good and bad behavior)?

Relational databases tend to have bigger and more complicated protocols, with more complex session management, data types and parsing requirements, and connections that may only support a single in-flight query.

Libraries just have to do more work, compared to simpler protocols, or HTTP which is incredibly easy to scale and pretty much handled automatically by the standard libraries at this point.

Re: Amazon DynamoDB Transactions

#74

Post by itcmcgrath »

airwot4 wrote: post #52
stickfigure wrote: post #28

Earlier quoted context omitted.

The Google Cloud Datastore (formerly the "App Engine Datastore") has had cross-entity-group transactions since 2011: https://googleappengine.blogspot.com/2011/10/app-engine-155-...

The cross group transactions are a little limited - https://cloud.google.com/appengine/docs/standard/java/datast... I don't think it's fair to compare them. However, the more recent Google storage offerings based on Cloud Spanner do seem to offer this. I don't see how Amazon can make this statement - that doesn't stop it being an excellent enhancement to DynamoDB though.

DynamoDB is limited to 10 items, whereas the Cloud Datastore limits are 25 different 'tables' -> The new version via Cloud Firestore doesn't even have that restriction. AWS is several years behind and several NoSQL systems behind in this area. Still, a cool addition.

Re: Amazon DynamoDB Transactions

#75

Post by itcmcgrath »

otterley wrote: post #41
stickfigure wrote: post #28

Earlier quoted context omitted.

The Google Cloud Datastore (formerly the "App Engine Datastore") has had cross-entity-group transactions since 2011: https://googleappengine.blogspot.com/2011/10/app-engine-155-...

The “and tables” clause is the differentiator, I think. DynamoDB tables are roughly equivalent to Datastore namespaces; I don’t believe Google Cloud Datastore supports cross-namespace transactions.

It does, and has for several years.

Re: Amazon DynamoDB Transactions

#76

Post by itcmcgrath »

otterley wrote: post #71
wsh91 wrote: post #70

Earlier quoted context omitted.

a) Cloud Firestore supports transactions across the entire database. You can learn more about them here: https://cloud.google.com/firestore/docs/manage-data/transact... . b) Given that the primary use case for namespaces was/is multitenancy, it's not clear to me why you'd want to transact across them. Nevertheless, you can. What's leading you to draw this conclusion?

The documentation is what led me to that conclusion, since it's not explicit as to what the transaction boundaries are, but I could be mistaken. Does this mean that the poster's claim is erroneous?

It does. It's not in the documentation because it doesn't have boundaries within the database.

Re: Amazon DynamoDB Transactions

#77

Post by otterley »

itcmcgrath wrote: post #76
otterley wrote: post #71

Earlier quoted context omitted.

The documentation is what led me to that conclusion, since it's not explicit as to what the transaction boundaries are, but I could be mistaken. Does this mean that the poster's claim is erroneous?

It does. It's not in the documentation because it doesn't have boundaries within the database.

Can you have more than one database per project? If so, there still might be a valid claim here.
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