5 ms·

They're hard if you can't tolerate downtime, which most production users can't. While that's true for a lot of database systems, some more recently designed ar

They're hard if you can't tolerate downtime, which most production users can't. While that's true for a lot of database systems, some more recently designed are much better. [1] [1]: https://www.cockroachlabs.com/docs/stable/upgrade-cockroach-version.html https://www.cockroachlabs.com/docs/stable/upgrade-cockroach-...

nix23 4y ago
zero-downtime-postgres-migration-done-right: https://engineering.theblueground.com/blog/zero-downtime-postgres-migration-done-right/ https://engineering.theblueground.com/blog/zero-downtime-pos...
- wutwutwutwut 4y ago
  Would you consider that a piece of cake? I have doubts. The page you linked to describes that if you follow the instructions on many other blogs you'll have data loss. Not a symptom of a piece of cake process
  - nix23 4y ago
    If you need zero downtime, you already in a field where NOTHING is a piece of cake. Not your network, not your computing, not your storage, and i haven't even talked about the human aspect of "zero downtime".
    - wutwutwutwut 4y ago
      Alright. But the GP comment claimed upgrading PG was a piece of cake. You claim it is not a piece of cake. So it sounds like you agree that the claim that upgrading PG was a piece of cake was misleading.
      - msbarnett 4y ago
        > the GP comment claimed upgrading PG was a piece of cake. You claim it is not a piece of cake. So it sounds like you agree that the claim that upgrading PG was a piece of cake was misleading. GP claimed upgrading was a piece of cake, not that zero downtime upgrades are a piece of cake. The two claims aren’t interchangeable. The simple upgrade path is always available, though it may have downtime consequences you personally are unwilling to accept. And the complex upgrade path is complex for reasons that have nothing to do with PostgreSQL - it’s just as complex to do a zero downtime upgrade in any data store, because in all cases it requires logical replication. So if anything it feels like you’re the one being misleading by acting as though GP made a more specific claim than they actually did, and insisting that the hard case is hard because of PG instead of difficulty that’s inherent to the zero downtime requirement.
        wutwutwutwut 4y ago
        So if I tell you that upgrading pretty much all databases is a piece of cake but not include the criteria "unless you want to keep your data" you would say that is a fair statement? If you claim that process X is trivial one has to make some assumptions, right? Otherwise I could claim that going to the moon is trivial but leave out "assuming you have a rocket, resources, people and anything else you may require". Claiming that something is a piece of cake as a broad statement without any details is meaningless at best.
        msbarnett 4y ago
        > So if I tell you that upgrading pretty much all databases is a piece of cake but not include the criteria "unless you want to keep your data" you would say that is a fair statement? Incredibly bad-faith comparison, this. Many, many datastore deployments can tolerate 10 minutes of downtime every 4 or 5 years when their PG install finally transitions out of support. Data loss isn’t even in the same universe of problem. It’s reasonable to talk about how easy it is to upgrade if you can tolerate a tiny bit of downtime every few years, since most people can. It’s utterly asinine to compare that to data deletion.
urthor 4y ago
Blue green deployment is, while it requires a professional, is not particularly complex or unusual. Postgres is a tool. It can do many things, but the tool cannot run your entire business.
- amtamt 4y ago
  "Postres is a tool. It can do many things, but the tool cannot run your entire business." this is something majority of the decision makers pretend to don't understand (and sometimes really don't).
BiteCode_dev 4y ago
My experience is the opposite. Most productions users can tolerate downtime. It's usually the company leadership that can't tolerate it to have downtime. And it's fact, they are hit an unplanned with downtime of one service or the other every month or so because of an outage. They are used to it. So if you plan for it, explain it, and limit the scope and time of it, it usually goes very well unless you are a fortune 500, a hospital or something alike.
- sascha_sl 4y ago
  I think you really underestimate the amount of dependencies (documented and otherwise) that exist in even medium sized company. I once caused a production outage in a retail company that caused all cash registers to stop working. The team that worked on that had pushed in a last minute change and didn't test if it handed going offline gracefully. Right now I'm on call for an identity provider used by people in various timezones, including logistics workers in places that operate 24/7. Even when we do weekend upgrades, we still cause quite a bit of collateral damage. 10 minutes of time, multiply by the number of employees affected. It adds up fast.
- fmajid 4y ago
  I’d say a system not designed to support maintenance is not properly architected. You will need maintenance windows for an individual subsystem to perform OS upgrades, DB upgrades are no different and Postgres upgrades using pg_upgrade are relatively painless, provided you test them first in CI or against production snapshots, something the author’s company seemingly lacks.
  - amtamt 4y ago
    "a system not designed to support maintenance is not properly architected" Indeed, but who cares about the system design anymore? How many companies/ teams can claim honestly they even had a person with proper DBA competency, while features over features were added in sprints doing the minimum required to get the feature shipped out at the soonest possible (usually one DB schema change with feature and then one or more to add index due to performance regressions)? DBA competency is only sought when DB schema has fubar'd to an extent that frequent outages are norms or the version used is EOL'd by a few months at least. And by that time the people who "designed" the system are gone, not having documented ever why a given decision was made. And that is how my friend... DB upgrades are hard.
cersa8 4y ago
CockroachDB and others come with huge downsides in performance and features. I keep trying to see of these databases are a good fit for me but just the sheer time it takes to import my database makes me shudder. I've used the Aws cloud hosted free tier of CockroachDB but ran into transaction timeouts on very moderate loads. There is a reason these databases aren't seeing massive uptake despite their lofty promises.
- billythemaniam 4y ago
  Yeah CockroachDB suffers from the same problem as PG: the defaults kinda suck for certain workloads. CockroachDB has an additional problem that their documentation isn't as detailed as PG so it can be hard to know what to tune. TiDB and Spanner defaults are much better for a wider range of workloads.
  - vvern 4y ago
    Can you say more about workloads which suck for either of the two databases at their default settings?

nix23 4y ago

zero-downtime-postgres-migration-done-right: https://engineering.theblueground.com/blog/zero-downtime-postgres-migration-done-right/ https://engineering.theblueground.com/blog/zero-downtime-pos...

wutwutwutwut 4y ago
Would you consider that a piece of cake? I have doubts. The page you linked to describes that if you follow the instructions on many other blogs you'll have data loss. Not a symptom of a piece of cake process
- nix23 4y ago
  If you need zero downtime, you already in a field where NOTHING is a piece of cake. Not your network, not your computing, not your storage, and i haven't even talked about the human aspect of "zero downtime".
  - wutwutwutwut 4y ago
    Alright. But the GP comment claimed upgrading PG was a piece of cake. You claim it is not a piece of cake. So it sounds like you agree that the claim that upgrading PG was a piece of cake was misleading.
    - msbarnett 4y ago
      > the GP comment claimed upgrading PG was a piece of cake. You claim it is not a piece of cake. So it sounds like you agree that the claim that upgrading PG was a piece of cake was misleading. GP claimed upgrading was a piece of cake, not that zero downtime upgrades are a piece of cake. The two claims aren’t interchangeable. The simple upgrade path is always available, though it may have downtime consequences you personally are unwilling to accept. And the complex upgrade path is complex for reasons that have nothing to do with PostgreSQL - it’s just as complex to do a zero downtime upgrade in any data store, because in all cases it requires logical replication. So if anything it feels like you’re the one being misleading by acting as though GP made a more specific claim than they actually did, and insisting that the hard case is hard because of PG instead of difficulty that’s inherent to the zero downtime requirement.
      - wutwutwutwut 4y ago
        So if I tell you that upgrading pretty much all databases is a piece of cake but not include the criteria "unless you want to keep your data" you would say that is a fair statement? If you claim that process X is trivial one has to make some assumptions, right? Otherwise I could claim that going to the moon is trivial but leave out "assuming you have a rocket, resources, people and anything else you may require". Claiming that something is a piece of cake as a broad statement without any details is meaningless at best.
        msbarnett 4y ago
        > So if I tell you that upgrading pretty much all databases is a piece of cake but not include the criteria "unless you want to keep your data" you would say that is a fair statement? Incredibly bad-faith comparison, this. Many, many datastore deployments can tolerate 10 minutes of downtime every 4 or 5 years when their PG install finally transitions out of support. Data loss isn’t even in the same universe of problem. It’s reasonable to talk about how easy it is to upgrade if you can tolerate a tiny bit of downtime every few years, since most people can. It’s utterly asinine to compare that to data deletion.

urthor 4y ago

Blue green deployment is, while it requires a professional, is not particularly complex or unusual. Postgres is a tool. It can do many things, but the tool cannot run your entire business.

amtamt 4y ago
"Postres is a tool. It can do many things, but the tool cannot run your entire business." this is something majority of the decision makers pretend to don't understand (and sometimes really don't).

BiteCode_dev 4y ago

My experience is the opposite. Most productions users can tolerate downtime. It's usually the company leadership that can't tolerate it to have downtime. And it's fact, they are hit an unplanned with downtime of one service or the other every month or so because of an outage. They are used to it. So if you plan for it, explain it, and limit the scope and time of it, it usually goes very well unless you are a fortune 500, a hospital or something alike.

sascha_sl 4y ago
I think you really underestimate the amount of dependencies (documented and otherwise) that exist in even medium sized company. I once caused a production outage in a retail company that caused all cash registers to stop working. The team that worked on that had pushed in a last minute change and didn't test if it handed going offline gracefully. Right now I'm on call for an identity provider used by people in various timezones, including logistics workers in places that operate 24/7. Even when we do weekend upgrades, we still cause quite a bit of collateral damage. 10 minutes of time, multiply by the number of employees affected. It adds up fast.
fmajid 4y ago
I’d say a system not designed to support maintenance is not properly architected. You will need maintenance windows for an individual subsystem to perform OS upgrades, DB upgrades are no different and Postgres upgrades using pg_upgrade are relatively painless, provided you test them first in CI or against production snapshots, something the author’s company seemingly lacks.
- amtamt 4y ago
  "a system not designed to support maintenance is not properly architected" Indeed, but who cares about the system design anymore? How many companies/ teams can claim honestly they even had a person with proper DBA competency, while features over features were added in sprints doing the minimum required to get the feature shipped out at the soonest possible (usually one DB schema change with feature and then one or more to add index due to performance regressions)? DBA competency is only sought when DB schema has fubar'd to an extent that frequent outages are norms or the version used is EOL'd by a few months at least. And by that time the people who "designed" the system are gone, not having documented ever why a given decision was made. And that is how my friend... DB upgrades are hard.

cersa8 4y ago

CockroachDB and others come with huge downsides in performance and features. I keep trying to see of these databases are a good fit for me but just the sheer time it takes to import my database makes me shudder. I've used the Aws cloud hosted free tier of CockroachDB but ran into transaction timeouts on very moderate loads. There is a reason these databases aren't seeing massive uptake despite their lofty promises.

billythemaniam 4y ago
Yeah CockroachDB suffers from the same problem as PG: the defaults kinda suck for certain workloads. CockroachDB has an additional problem that their documentation isn't as detailed as PG so it can be hard to know what to tune. TiDB and Spanner defaults are much better for a wider range of workloads.
- vvern 4y ago
  Can you say more about workloads which suck for either of the two databases at their default settings?