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RDS, or any hosted database solution, is not some kind of silver bullet that solves all problems. While it's true it takes care of backups automatically, it doe

RDS, or any hosted database solution, is not some kind of silver bullet that solves all problems. While it's true it takes care of backups automatically, it does also restrict you in terms of what you can do. For example, you can't load custom extensions into RDS. Also, to the best of my knowledge RDS does not support a hot standby replica you can use for read-only queries, and replication between RDS and non RDS is also not supported. This means you can't balance load between multiple hosts, unless you're OK with running a multi-master setup (of which I'm not sure how well this would play out on RDS). Most important of all, we ship PostgreSQL as part of our Omnibus package. As a result the best way of testing this over time is to use it ourselves, something we strive to do with everything we sihp. This means we need to actually run our own things. Using a hosted database would mean we wouldn't be using a part of what we ship, thus not being able to test it over time.

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wahnfrieden 10y ago
You can use the failover standby replica for reads with Aurora at least. And you can manually via MySQL set up replication with non RDS, just not via AWS APIs.
phonon 10y ago
> Also, to the best of my knowledge RDS does not support a hot standby replica you can use for read-only queries RDS has very nice Read Replicas. http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ReadRepl.html http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_R... For HA you can use High Availability (Multi-AZ). http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.MultiAZ.html http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concep...
- deleted 10y ago
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- cjbprime 10y ago
  That said, it did take AWS a disturbingly long time to add support for Postgres read replicas.
  - grzm 10y ago
    Why disturbingly long? As opposed to frustratingly long? Or something else? What does the time it took Amazon to add such support imply to you?
    - cjbprime 10y ago
      You're welcome to read frustratingly. I didn't think hard about the word choice. I suppose disturbingly is meant to imply "It was frustrating to me, and I think it would be frustrating to anyone in the situation of seriously using Postgres on RDS[1], and perhaps it ought to even decrease their opinion of the RDS team's ability to prioritize and ship features that are production-ready". Does that make sense? [1]: There was no workaround for getting a read replica. RDS doesn't allow you to run replication commands. So your options were "Don't use Postgres on RDS, or don't run queries against up-to-date copies of databases." There was never any announcement of when read replicas were coming. It was arguably irresponsible of them to release Postgres on RDS as a product and then wait a year to support read replicas, which is a core feature that other DB backends had already.
      - grzm 10y ago
        Without insight into what the AWS RDS team workload and priorities are, I think it's unfair to use a term like disturbingly. Sure, as a user, we want features to be rolled out as quickly as possible. From what I've seen, Postgres RDS support has been slow, but consistently getting better: nothing to warrant suggesting Amazon isn't serious about continuing to improve their Postgres offering. That would be disturbing. Or data loss failures. Slower-than-I'd-like roll-out of new features? Frustrating. By all means, RDS isn't perfect. It doesn't suit my current needs. But I understand that getting these things to work in a managed way that suits the needs of most customers is not an easy task. I'll remain frustrated in some small way until RDS does suit my needs. I hope they continue to add features to give customers more flexibility. And from what I've seen, they likely will.
- YorickPeterse 10y ago
  Aha, I probably overlooked read replicas (haven't used RDS in about 1.5 years).
- dcosson 10y ago
  But to be fair if you enable both you're paying for 3 servers total instead of 2, you can't read from the HA standby. (I'd imagine there are reasons not to do that anyway, but you don't even have the option of making that compromise to save on the cost)
  - phonon 10y ago
    Well, you can use the Read Replica only, and if you have an outage on the primary, promote the Read Replica to recover... (will take a few minutes though.) In general though-- TANSTAAFL
  - illumin8 10y ago
    With RDS Aurora, any of your read replicas can be promoted to read/write master in the event of a failure of your primary master. This happens in 10-15 seconds, and is very fast. So, you can get the benefit of up to 15 read replicas, and not have to pay for an extra standby server that is sitting idle.
carterehsmith 10y ago
>> RDS does not support a hot standby replica you can use for read-only queries This is not true anymore. I set up two read-only RDS replicas, one in a different AWS region, and another in the same region, for read-only queries, just by clicking in AWS console.

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wahnfrieden 10y ago

You can use the failover standby replica for reads with Aurora at least. And you can manually via MySQL set up replication with non RDS, just not via AWS APIs.

phonon 10y ago

> Also, to the best of my knowledge RDS does not support a hot standby replica you can use for read-only queries RDS has very nice Read Replicas. http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ReadRepl.html http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_R... For HA you can use High Availability (Multi-AZ). http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.MultiAZ.html http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concep...

deleted 10y ago
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cjbprime 10y ago
That said, it did take AWS a disturbingly long time to add support for Postgres read replicas.
- grzm 10y ago
  Why disturbingly long? As opposed to frustratingly long? Or something else? What does the time it took Amazon to add such support imply to you?
  - cjbprime 10y ago
    You're welcome to read frustratingly. I didn't think hard about the word choice. I suppose disturbingly is meant to imply "It was frustrating to me, and I think it would be frustrating to anyone in the situation of seriously using Postgres on RDS[1], and perhaps it ought to even decrease their opinion of the RDS team's ability to prioritize and ship features that are production-ready". Does that make sense? [1]: There was no workaround for getting a read replica. RDS doesn't allow you to run replication commands. So your options were "Don't use Postgres on RDS, or don't run queries against up-to-date copies of databases." There was never any announcement of when read replicas were coming. It was arguably irresponsible of them to release Postgres on RDS as a product and then wait a year to support read replicas, which is a core feature that other DB backends had already.
    - grzm 10y ago
      Without insight into what the AWS RDS team workload and priorities are, I think it's unfair to use a term like disturbingly. Sure, as a user, we want features to be rolled out as quickly as possible. From what I've seen, Postgres RDS support has been slow, but consistently getting better: nothing to warrant suggesting Amazon isn't serious about continuing to improve their Postgres offering. That would be disturbing. Or data loss failures. Slower-than-I'd-like roll-out of new features? Frustrating. By all means, RDS isn't perfect. It doesn't suit my current needs. But I understand that getting these things to work in a managed way that suits the needs of most customers is not an easy task. I'll remain frustrated in some small way until RDS does suit my needs. I hope they continue to add features to give customers more flexibility. And from what I've seen, they likely will.
YorickPeterse 10y ago
Aha, I probably overlooked read replicas (haven't used RDS in about 1.5 years).
dcosson 10y ago
But to be fair if you enable both you're paying for 3 servers total instead of 2, you can't read from the HA standby. (I'd imagine there are reasons not to do that anyway, but you don't even have the option of making that compromise to save on the cost)
- phonon 10y ago
  Well, you can use the Read Replica only, and if you have an outage on the primary, promote the Read Replica to recover... (will take a few minutes though.) In general though-- TANSTAAFL
- illumin8 10y ago
  With RDS Aurora, any of your read replicas can be promoted to read/write master in the event of a failure of your primary master. This happens in 10-15 seconds, and is very fast. So, you can get the benefit of up to 15 read replicas, and not have to pay for an extra standby server that is sitting idle.

carterehsmith 10y ago

>> RDS does not support a hot standby replica you can use for read-only queries This is not true anymore. I set up two read-only RDS replicas, one in a different AWS region, and another in the same region, for read-only queries, just by clicking in AWS console.