6 ms·

Seems like overkill, and just a shiny new toy to play with for this use case. Stackoverflow.com uses SQL. You aren't exceeding stackoverflow. In a couple of yea

Seems like overkill, and just a shiny new toy to play with for this use case. Stackoverflow.com uses SQL. You aren't exceeding stackoverflow. In a couple of years they'll migrate back, or to something else. The whole point of cdb is to enable things like Google scale. But all I ever see on it are random devs spinning up three nodes and being so proud. Which is too bad because I'd love to see someone pushing its limits, and betting mission critical services on it that nothing else could handle.

Keverw 7y ago
I could see the benefits though. If you get popular, you can just throw more hardware at it instead of feeling rushed to switch databases or start sharding in the application level. One downsides I didn't like though is no incremental backups unless enterprise. There's PG dump but not sure if it'd work on a bunch of threads and stuff. If using MySQL there's the MyDumper project that looked interesting. Then there's no full text search is a downside, but I know it seems people recommend running a separate search solution anyways so that can be a little slow to get started. Easier if you could just run it in one system in the beginning, and who knows maybe search isn't a bottleneck anyways depending on the implementation of the database or you want to be able to still full text search while debugging maybe. Then no geospatial can be a downside for some types of businesses or use cases, say a place lookup, factoring it into a game matching algo, etc. I've been really interested in MongoDB lately though, but was playing with a few newer SQL based databases for what to use on my own project. Then I know some companies actually run multiple databases too, some stuff might be noSQL while other workloads are SQL databases too, but I know some rather just one a single database so only one source of truth. Then I know PostgreSQL has the idea of foreign data wrappers [0], so I guess then you could treat a MongoDB collection as a table. So maybe you had a users collection, you could join on it I think using this but never played with it. However this seems mostly Postgre itself, other Postgre compatible databases don't implement this as far as I can tell. However I believe even MongoDB with it sharding can't handle GEO unless you separate that data in a unsharded collection, which is then placed on any replica set in the cluster. So maybe you could split geo results up by city level in different collections but then if you wanted to find near by things that could go into other cities based on the radius, you'd have to write your own logic. Unsure how larger sites like say Yelp handles GEO lookups. Only big downside I see with MongoDB though is no joins, so say you had a social networking site and wanted to hide posts by users suspended from the results, you'd have to write your own logic to do so. I think it'd be so cool if you could like symlink a value from one document to another. I think OrientDB has something like that though. I was asking a friend who uses Mongo for advice, apparently in that case you'd just update every single post when you suspend that user - not sure if that's really efficient or not but I doubt a single user would have millions of posts... So probably less than 10K posts at the most maybe. However I guess with social feeds themselves, seems it recommend to fan out on write instead of fanning out on read, so in a way you can sometimes precompute things to help the database. All about making decisions and tradeoffs I guess. [0] https://wiki.postgresql.org/wiki/Foreign_data_wrappers https://wiki.postgresql.org/wiki/Foreign_data_wrappers
- notyourday 7y ago
  > I could see the benefits though. If you get popular You won't get that popular. And if you do, replacing database layer would be a party with cases of champagne.
  - Keverw 7y ago
    Yep, I heard people throw parties after successful migrations, but it sounds like once you pick a database you are sorta married to it and rewriting things could be a pain if a large or complex application. Then live migrating could be a challenge also unless you are ok with some downtime. So I feel like if it's possible to get it right from the beginning by picking the right tech for scaling, it's worth it then.
    - notyourday 7y ago
      That's premature optimization.
- burpsnard 7y ago
  sounds like a 70's IBM COBOL VSAM batch job jcl script
irfansharif 7y ago
As someone working for crdb, I disagree with you re: "the whole point is that it enables Google scale". There's a wide gulf up to that point that cockroachdb is still imminently useful for, especially considering the alternatives.
koolba 7y ago
Does StackOverflow use a single SQL Server databases for all writes for the entire platform? They must at least have read replicas given the traffic for the site.
- taspeotis 7y ago
  https://stackexchange.com/performance https://stackexchange.com/performance
  - no_wizard 7y ago
    This is a surprisingly small amount of infrastructure considering its size
    - thrower123 7y ago
      It just highlights how overcomplicated most setups are, really. I feel like you need more hardware than that for a hello world kubernetes tutorial...
- janee 7y ago
  Some more info if interested https://news.ycombinator.com/item?id=15427124 https://news.ycombinator.com/item?id=15427124 Bit outdated but probably still holds true. It's pretty amazing what SQL Server can do...just wish it wasn't so expensive
latch 7y ago
Sorry if I wasn't clear, but the goal of the migration wasn't for scale, it was for HA. I find it difficult to setup PostgreSQL without having a single point of failure and introducing downtime for things such as upgrades. We aren't doing life changing stuff, true, but a downtime in our system can result in employees (often at the bottom of the economic ladder) not being able to get to work. That gnaws at me. I guess the better alternative is to go for a hosted approach, but that isn't without its own complications and challenges.
- briandilley 7y ago
  > I find it difficult to setup PostgreSQL without having a single point of failure and introducing downtime for things such as upgrades. Amazon does this with RDS, and so can you. This really isn't very tough to achieve with replicas. And for upgrades you just add a new replica with the latest version and promote it to master and replace the remaining nodes one at a time.
  - skj 7y ago
    Man I love technical advice that has the word "just" in it. It's so simple!
  - shawabawa3 7y ago
    RDS absolutely has downtime for upgrades, and even for master switchover
- aprdm 7y ago
  Out of curiosity what do you feel so hard to set up with PostgreSQL? Having a master with a read replica and then making the read replica the master in case the master goes down seems to be a very well known methodology. You can use a virtual ip with both servers behind it (keepalived) or a 0 ttl DNS solution (consul). Is you case more complex than that? With master to master replication I feel there are couple of gotchas and you need to design your data in a way to avoid conflict as much as you can. A solution like bdr seems to be an off-the-shelf one that is proven. I haven't really upgraded postgres in a rapid fashion, usually just keep with whatever version comes with the OS package manager forever.. or whatever docker image I start it with. I guess the same approach for HA can be used to upgrade one at a time, am assuming postgres doesn't break backwards compatibility very often. You can either automate the failover or have a system to SMS you when it happens. I like to do it manually personally since I have seen the automated failover fail more times than the manual procedure. I have probably managed over 30 postgres instances in my services that have grown up to 1/2 PB of data and I've never had a single issue with it... postgres, redis, rabbitmq, consul are technologies that you RTFM, set it up, and it just works! I wouldn't trust a technology that isn't established and widely adopted which is how I see cockroachdb a the moment.
manigandham 7y ago
CRDB is also a relational database, and often used for highly-available and durable deployments rather than purely for scaling.
kccqzy 7y ago
If devs don't play with a database in an unimportant project to gain some experience, how would they be confident in "betting mission critical services on it" then?

Keverw 7y ago

I could see the benefits though. If you get popular, you can just throw more hardware at it instead of feeling rushed to switch databases or start sharding in the application level. One downsides I didn't like though is no incremental backups unless enterprise. There's PG dump but not sure if it'd work on a bunch of threads and stuff. If using MySQL there's the MyDumper project that looked interesting. Then there's no full text search is a downside, but I know it seems people recommend running a separate search solution anyways so that can be a little slow to get started. Easier if you could just run it in one system in the beginning, and who knows maybe search isn't a bottleneck anyways depending on the implementation of the database or you want to be able to still full text search while debugging maybe. Then no geospatial can be a downside for some types of businesses or use cases, say a place lookup, factoring it into a game matching algo, etc. I've been really interested in MongoDB lately though, but was playing with a few newer SQL based databases for what to use on my own project. Then I know some companies actually run multiple databases too, some stuff might be noSQL while other workloads are SQL databases too, but I know some rather just one a single database so only one source of truth. Then I know PostgreSQL has the idea of foreign data wrappers [0], so I guess then you could treat a MongoDB collection as a table. So maybe you had a users collection, you could join on it I think using this but never played with it. However this seems mostly Postgre itself, other Postgre compatible databases don't implement this as far as I can tell. However I believe even MongoDB with it sharding can't handle GEO unless you separate that data in a unsharded collection, which is then placed on any replica set in the cluster. So maybe you could split geo results up by city level in different collections but then if you wanted to find near by things that could go into other cities based on the radius, you'd have to write your own logic. Unsure how larger sites like say Yelp handles GEO lookups. Only big downside I see with MongoDB though is no joins, so say you had a social networking site and wanted to hide posts by users suspended from the results, you'd have to write your own logic to do so. I think it'd be so cool if you could like symlink a value from one document to another. I think OrientDB has something like that though. I was asking a friend who uses Mongo for advice, apparently in that case you'd just update every single post when you suspend that user - not sure if that's really efficient or not but I doubt a single user would have millions of posts... So probably less than 10K posts at the most maybe. However I guess with social feeds themselves, seems it recommend to fan out on write instead of fanning out on read, so in a way you can sometimes precompute things to help the database. All about making decisions and tradeoffs I guess. [0] https://wiki.postgresql.org/wiki/Foreign_data_wrappers https://wiki.postgresql.org/wiki/Foreign_data_wrappers

notyourday 7y ago
> I could see the benefits though. If you get popular You won't get that popular. And if you do, replacing database layer would be a party with cases of champagne.
- Keverw 7y ago
  Yep, I heard people throw parties after successful migrations, but it sounds like once you pick a database you are sorta married to it and rewriting things could be a pain if a large or complex application. Then live migrating could be a challenge also unless you are ok with some downtime. So I feel like if it's possible to get it right from the beginning by picking the right tech for scaling, it's worth it then.
  - notyourday 7y ago
    That's premature optimization.
burpsnard 7y ago
sounds like a 70's IBM COBOL VSAM batch job jcl script

irfansharif 7y ago

As someone working for crdb, I disagree with you re: "the whole point is that it enables Google scale". There's a wide gulf up to that point that cockroachdb is still imminently useful for, especially considering the alternatives.

koolba 7y ago

Does StackOverflow use a single SQL Server databases for all writes for the entire platform? They must at least have read replicas given the traffic for the site.

taspeotis 7y ago
https://stackexchange.com/performance https://stackexchange.com/performance
- no_wizard 7y ago
  This is a surprisingly small amount of infrastructure considering its size
  - thrower123 7y ago
    It just highlights how overcomplicated most setups are, really. I feel like you need more hardware than that for a hello world kubernetes tutorial...
janee 7y ago
Some more info if interested https://news.ycombinator.com/item?id=15427124 https://news.ycombinator.com/item?id=15427124 Bit outdated but probably still holds true. It's pretty amazing what SQL Server can do...just wish it wasn't so expensive

latch 7y ago

Sorry if I wasn't clear, but the goal of the migration wasn't for scale, it was for HA. I find it difficult to setup PostgreSQL without having a single point of failure and introducing downtime for things such as upgrades. We aren't doing life changing stuff, true, but a downtime in our system can result in employees (often at the bottom of the economic ladder) not being able to get to work. That gnaws at me. I guess the better alternative is to go for a hosted approach, but that isn't without its own complications and challenges.

briandilley 7y ago
> I find it difficult to setup PostgreSQL without having a single point of failure and introducing downtime for things such as upgrades. Amazon does this with RDS, and so can you. This really isn't very tough to achieve with replicas. And for upgrades you just add a new replica with the latest version and promote it to master and replace the remaining nodes one at a time.
- skj 7y ago
  Man I love technical advice that has the word "just" in it. It's so simple!
- shawabawa3 7y ago
  RDS absolutely has downtime for upgrades, and even for master switchover
aprdm 7y ago
Out of curiosity what do you feel so hard to set up with PostgreSQL? Having a master with a read replica and then making the read replica the master in case the master goes down seems to be a very well known methodology. You can use a virtual ip with both servers behind it (keepalived) or a 0 ttl DNS solution (consul). Is you case more complex than that? With master to master replication I feel there are couple of gotchas and you need to design your data in a way to avoid conflict as much as you can. A solution like bdr seems to be an off-the-shelf one that is proven. I haven't really upgraded postgres in a rapid fashion, usually just keep with whatever version comes with the OS package manager forever.. or whatever docker image I start it with. I guess the same approach for HA can be used to upgrade one at a time, am assuming postgres doesn't break backwards compatibility very often. You can either automate the failover or have a system to SMS you when it happens. I like to do it manually personally since I have seen the automated failover fail more times than the manual procedure. I have probably managed over 30 postgres instances in my services that have grown up to 1/2 PB of data and I've never had a single issue with it... postgres, redis, rabbitmq, consul are technologies that you RTFM, set it up, and it just works! I wouldn't trust a technology that isn't established and widely adopted which is how I see cockroachdb a the moment.

manigandham 7y ago

CRDB is also a relational database, and often used for highly-available and durable deployments rather than purely for scaling.

kccqzy 7y ago

If devs don't play with a database in an unimportant project to gain some experience, how would they be confident in "betting mission critical services on it" then?