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Why does everyone run ancient Postgres versions?

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Re: Why does everyone run ancient Postgres versions?

#301

Post by kayodelycaon »

LaGrange wrote: post #217
Dalewyn wrote: post #128

Earlier quoted context omitted.

One of the first laws of the universe that a good engineer learns is: Do not fix what is not broken. And no, being old is not broken.

One of the first laws of universe that an experienced engineer learns is that "do not fix what is not broken" never actually applies, and is only brought up by people invulnerable to consequences. That doesn't mean "upgrade recklessly," but it does mean you should know _why_ you're either upgrading or _NOT_ upgrading. That's your job, much more than the act of upgrading itself. Unpublished vulnerabilities in old soft…

I generally follow if it’s not broken, fixes need to be carefully planned. I can’t tell you how many times I thought I’d quickly do an upgrade and things would go wrong, like all of my home automation stop working right before bed.

Re: Why does everyone run ancient Postgres versions?

#302

Post by Too »

forinti wrote: post #284
literalAardvark wrote: post #268

Earlier quoted context omitted.

> It couldn't be easier If you have a trivial database, yes. If you have a large, complicated database that takes hours/days to restore and has an HA SLA, very hell no.

That's not going to be easy with any database.

With mongodb in a HA setup you can perform a staggered upgrade of individual nodes in the cluster with no downtime. Very smooth in my experience.

Re: Why does everyone run ancient Postgres versions?

#303

Post by ttfkam »

sgarland wrote: post #254
phil21 wrote: post #185

Earlier quoted context omitted.

My opinion is Postgres was designed by software developers for software developers. The split on “which relational database to use” in my career has almost always been perfectly split between SWE vehemently demanding pgsql for the feature set, and the sysadmins having to support maintenance and production availability preferring MySQL. One of the few things I’ve enjoyed with the move into devops and companies forcing…

> The split on “which relational database to use” in my career has almost always been perfectly split between SWE vehemently demanding pgsql for the feature set I’ve seen this as well, but when pressed, none of them could articulate what part of its feature set they actually needed to use. > One of the few things I’ve enjoyed with the move into devops and companies forcing previously “pure” developers into operationa…

> My experience has been that they spin up either a hideously under or over-provisioned RDS or Aurora instance, and then never touch it until it breaks

That's a true shame considering how easy it is to make a read replica of any size and then fail over to it as the new primary. Definite skill issues.

Re: Why does everyone run ancient Postgres versions?

#304

Post by chefandy »

tgv wrote: post #189
noirscape wrote: post #156

Because the actual process of upgrading Postgres is terrible. I say this as someone who absolutely loves using it, but the actual process of upgrading Postgres is something that takes significant downtime, is error-prone and you're often better off just dumping all the databases and reimporting them in a new folder. (A good idea in general since it'll vacuum and compact indexes as well if you do it, combining a few m…

ADd to that: if it works, don't fix it.

And considering how many people use some sort of abstraction layer like an ORM, have databases installed as part of some deployed application, or just do basic CRUD stuff, it probably would have worked on a postgres install from the 90s.

I keep an eye out for vulnerabilities, and that's about it.

Re: Why does everyone run ancient Postgres versions?

#305

Post by ttfkam »

jeltz wrote: post #286
paulryanrogers wrote: post #261

Earlier quoted context omitted.

What is this holding back? A redo based alternative to MVCC?

Nope, that is totally unrated. To support upgrade in place without an old version of PostgreSQL: 1. The new version of PostgreSQL would need to able to read all old catalog table formats and migrate them. 2. The new version of PostgreSQL would need to support all old versions of the parse tree to migrate views. 3. Likely a bunch of more things that I do not know of. I for example doubt it is trivial to just read an o…

It is a PITA, but I've written scripts that pg_dump just the schema, load the schema into the new db with the new version, set up logical replication between the two, wait for them to sync, reset all the sequences, and rebuild indexes before doing the handover.

It works with basically no downtime but I agree this kind of thing should definitely be easier, even turnkey.

Re: Why does everyone run ancient Postgres versions?

#306

Post by xvinci »

Dylan16807 wrote: post #133
xvinci wrote: post #115

Earlier quoted context omitted.

"What the application does" may not be what you think of, as it is dependent on how secure the application or the layers beneath it are. This is how people get everything pwned step by step. The database server may then reveal credentials to other apps etc.

If the database server has significant "other apps", which it probably doesn't.

Sure, but then chances are it's hosted on a nas with other data which you dont want ransomware'd, has access to other parts of the network, etc. - it's easy to underestimate the potential impact

Re: Why does everyone run ancient Postgres versions?

#307

Post by ttfkam »

homebrewer wrote: post #192
kstrauser wrote: post #172

Earlier quoted context omitted.

To be fair to PostgreSQL, it has multiple replication setups because they have different inherent properties. For instance, it comes with built in streaming and logical replication setups. Which should you use? It’s impossible to say without knowing your own exact use case. By analogy: should a database cluster optimize consistency or availability? Answer: there’s no way its author can guess which is more important t…

MySQL/MariaDB have binary and logical replication too. They also support much more advanced topologies like multi-master out of the box. It's just that what you need for 99% of situations relies on a well trodden path and requires no configuration at all. I have suspected for a long time that most people who criticize MySQL have never actually worked with it, or have done so a couple of decades ago. It's often the de…

Since v16, Postgres supports bidirectional logical replication out of the box. In other words, multiple writers.

Re: Why does everyone run ancient Postgres versions?

#308

Post by yxhuvud »

sofixa wrote: post #262
yxhuvud wrote: post #209

Earlier quoted context omitted.

In 2012 MySQL had several flavors of replications, each with its own very serious pitfalls that could introduce corruption or loss of data. I saw enough of MySQL replication issues in those days that I wouldn't want to use it. But sure, it was easy to get a proof of concept working. But when you tried to break it by turning off network and/or machines, then shit broke down in very broken ways that was not recoverable…

Maybe that was true in 2012 (maybe it was related to MyISAM) but by ~2015 with InnoDB MySQL replication was rock solid.

It was not related to MyISAM.

How did you verify that it was rock solid? And which of the variants did you use?

Re: Why does everyone run ancient Postgres versions?

#309

Post by efields »

bityard wrote: post #292

You might as well ask, why does anyone run an older version or anything? The reasons will be largely the same. Most of the software on my machines are "old" because they are part of a Linux distribution that (aside from security issues) was frozen in time a year or two ago so that it could be tested, released, and maintained. I am quite happy to have a system that I know is not going to break (either itself, or my wo…

These are the companies you want to be at IMHO. Provided the compensation is adequate, slow and stable > fast and pivot-y.

Re: Why does everyone run ancient Postgres versions?

#310

Post by ttfkam »

KaiserPro wrote: post #202
elric wrote: post #110

Lots of dogmatism in this discussion, it seems. A couple of things: 1. Most psql deployments are not exposed to the interwebz, they are typically only accessible to the applications that need them by virtue of network setup (firewalls etc). This limits the attack vector to whatever the application does. Good. 2. Distro vendors (RHEL et al) often stick to major psql release for the lifecycle of the OS version. If the…

Upgrading a datastore is a massive, massive risk. It requires a lot of work, planned downtime, or some way to smear updates across the estate. The cost of any failure is very high. The benefit of any major upgrade is also vanishingly small. Unless you need a specific feature, its just not worth it.

Or when the version is EOL, not getting security patches, and/or only compatible with an OS that isn't getting security updates.

…or you're on AWS RDS, which will automatically bump your db cluster if it goes EOL and you ignore the notices for more than a year.

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