4 ms·

I know about Paxos. I know when to use it, and when not to use it. Seeing as you came up with the example, using Paxos for an "Nth caller wins" is a really ba

I know about Paxos. I know when to use it, and when not to use it. Seeing as you came up with the example, using Paxos for an "Nth caller wins" is a really bad idea - the Nth caller to your switchboard likely won't be the one selected. You probably _need_ a single server system, like the example you wrote (but without the threading errors.)

haberman 15y ago
Then why would you compare dynamo and memcached? Or suggest that Amazon could use an in-memory cache as the primary store for shopping cart data? It makes no sense. If you want to be particular about ordering, then you can always use paxos to elect a master that handles everything serially and failsover.
- justinsb 15y ago
  I see you work at Google. How about advancing the conversation by telling us how Google stores its sessions?
  - haberman 15y ago
    Let's make a deal. I'll start "advancing the conversation" once you stop misleading people (ie. admit that your initial sweeping claims were incorrect).
    - justinsb 15y ago
      Deal. My initial sweeping claims were incorrect. So: How does Google store its sessions?
      - haberman 15y ago
        So I'm not an expert in Google's front-ends and I'm not sure that Google stores "sessions" in the way you'd generally think of them in web apps. But usually when we have requirements like what you'd need for sessions (highly available, low-latency, highly scalable) we use Megastore: http://www.cidrdb.org/cidr2011/Papers/CIDR11_Paper32.pdf http://www.cidrdb.org/cidr2011/Papers/CIDR11_Paper32.pdf http://www.readwriteweb.com/cloud/2011/02/megastore-googles-answer-to-no.php http://www.readwriteweb.com/cloud/2011/02/megastore-googles-... Megastore is a layer on top of Bigtable that adds indexing, synchronous replication across data centers, and ACID semantics within small partitions called "entity groups."
        justinsb 15y ago
        Good deal! Agree that traditional sessions are best avoided, but good to know that megastore is suitable for session data.

haberman 15y ago

Then why would you compare dynamo and memcached? Or suggest that Amazon could use an in-memory cache as the primary store for shopping cart data? It makes no sense. If you want to be particular about ordering, then you can always use paxos to elect a master that handles everything serially and failsover.

justinsb 15y ago
I see you work at Google. How about advancing the conversation by telling us how Google stores its sessions?
- haberman 15y ago
  Let's make a deal. I'll start "advancing the conversation" once you stop misleading people (ie. admit that your initial sweeping claims were incorrect).
  - justinsb 15y ago
    Deal. My initial sweeping claims were incorrect. So: How does Google store its sessions?
    - haberman 15y ago
      So I'm not an expert in Google's front-ends and I'm not sure that Google stores "sessions" in the way you'd generally think of them in web apps. But usually when we have requirements like what you'd need for sessions (highly available, low-latency, highly scalable) we use Megastore: http://www.cidrdb.org/cidr2011/Papers/CIDR11_Paper32.pdf http://www.cidrdb.org/cidr2011/Papers/CIDR11_Paper32.pdf http://www.readwriteweb.com/cloud/2011/02/megastore-googles-answer-to-no.php http://www.readwriteweb.com/cloud/2011/02/megastore-googles-... Megastore is a layer on top of Bigtable that adds indexing, synchronous replication across data centers, and ACID semantics within small partitions called "entity groups."
      - justinsb 15y ago
        Good deal! Agree that traditional sessions are best avoided, but good to know that megastore is suitable for session data.