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PostgreSQL 9.4 Released

postgresql.org

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Re: PostgreSQL 9.4 Released

#121

Post by qooleot »

masklinn wrote: post #60
qooleot wrote: post #44

Earlier quoted context omitted.

Since you're planning on doing some conceptual work with JSONB, just a heads upon one gotcha - duplicate properties are not allowed. I.E.: { task: "do stuff", task: "do other stuff" } which sometimes is useful when you have front-end data with an N-number of entries but its a form that serializes to an object instead of an array. There are other use cases too.

RFC4627 §2.2 ¶1 > The names within an object SHOULD be unique. RFC2119 §3 > [SHOULD], or the adjective "RECOMMENDED", mean that there may exist valid reasons in particular circumstances to ignore a particular item, but the full implications must be understood and carefully weighed before choosing a different course. Not allowing duplicate keys in JSON objects is very close the exact opposite of a gotcha. Allowing and…

No, it can be a gotcha because the json column type (which still exists and many may mistakenly use instead of the jsonb type) allows it:

select '{"foo": 1, "foo": 2}'::json; json ---------------------- {"foo": 1, "foo": 2} (1 row)

select '{"foo": 1, "foo": 2}'::jsonb; jsonb ------------ {"foo": 2} (1 row)

So technically, the gotcha is you have to remember to use jsonb instead of json, as well as json having a true "gotcha" and jsonb not having one.

Re: PostgreSQL 9.4 Released

#122

Post by norkakn »

digitalzombie wrote: post #22
k_sze wrote: post #7

Bye bye MongoDB.

How do you cluster in postgresql? Serious question, my prefer noSQL is cassandra and clustering is pretty easy. I ask this question every year and postgresql have not deliver this. If there is any, there are hardly any documentation on it.

Clustering is really, really hard.

Cassandra is one of the better ones out there, but you have to deal with its data model and weird consistency promises (which however weird you think they are, are weirder)

The correct way to cluster also changes dramatically depending on your use case. Sure there are things like RAC that promise to make it just work, but those don't scale more than a few nodes.

Mongo is kind of the worst in this - it clusters in one weird way, has bad tooling, and subtly destroys your data at scale.

The general philosophy with postgres is to do it right, or not do it. There are ways to do specific kinds of clustering, but all of them (just like mongo, oracle, etc) have a lot of nuances to them.

If you have a natural shard key, use a bunch of schemas and table inheritance, and eat the downtime during re-shards. Check out citus as well. They have their issues, but they can help you hook up what you need.

Re: PostgreSQL 9.4 Released

#124

Post by threeseed »

gthank wrote: post #88
klaruz wrote: post #59

Earlier quoted context omitted.

I think the problem is clustering is still very much a duct-tape situation in postgresql with no real clear consensus on how to build out a cluster. Postgres-XL looks great for scale out, but you need 4 independent types of servers. Even with all those moving parts, it doesn't provide availability. If you want fail-over, you need pacemaker for the data nodes with traditional sync replication, and something like VRRP…

If you honestly believe that all you have to do is stand up a bunch of instances of Mongo/Cassandra/whatever and you instantly get acceptable HA, then you need to read the [Jepsen series]( https://aphyr.com/tags/jepsen )

Setting up Mongo/Cassandra for HA is still several orders of magnitude less work than with PostgreSQL.

And there are plenty of options for dealing with the issues presented in those series.

Re: PostgreSQL 9.4 Released

#125

Post by curiously »

I just recently began using PostgreSQL albiet an older version. Does this 9.4 mean that MongoDB is now pretty much a dud? Being able to store, manipulate, query JSON data AND have SQL on a established wheel that have been proven reliable and polished far longer than the age of most other databases?

Are there any code examples (preferably Python) that show how to use JSONB? I'd love to see some examples on how to query every record that contains a key in a json, or order rows based on a value in a json object.

off topic: If Meteor.js implements PostgreSQL 9.4 I would seriously consider using it again. That and maybe make DDP scalable.

Re: PostgreSQL 9.4 Released

#126

Post by veidr »

arethuza wrote: post #38
gh02t wrote: post #17

Earlier quoted context omitted.

> we'd be in a much better place what code-archaeology is concerned. This sounds like a great setup for a sci-fi novel. 500 years into the future, the infrastructure their distant ancestors coded has begun to fail. Now Biff Miffington, code-archaeologist, must sift through millions of forgotten messages using a mysterious tool remembered only as "git." Its interface is arcane and the remaining messages broken, tainte…

Vernor Vinge's A Deepness in the Sky actually has a role described as "programmer archaeologist": http://en.wikipedia.org/wiki/A_Deepness_in_the_Sky#Interstel...

That is, btw, an absolutely fantastic distant future sci-fi novel. Among the best of all time. (Vinge doesn't consistently product books that good, but man that one is great.)

Re: PostgreSQL 9.4 Released

#127

Post by threeseed »

tensor wrote: post #111
nemo44x wrote: post #93

Earlier quoted context omitted.

This is exactly right. I can't believe how snide and ignorant a few of the commenters are (except I can because it's the same folks with the same FUD every time). MongoDB isn't standing still and it is getting better and better with every release. Not to mention there are 100's of massive projects running on MongoDB with success. Something about MongoDB really drives the Postgres community (and certain NoSQL DB fans)…

People here have a problem with it because it is a technically poor solution, even among nosql databases. The main problems are: 1. Historically mongodb was distributed with completely unsafe defaults. It was insane to use it with any data you actually cared about. Once you toggle on the safety features most of the vaunted performance goes away. 2. It doesn't actually scale that well despite claims that it does. The…

You know what I don't like. People who complain about technologies they've never used.

1. This was NEVER an issue for 99.999% of people. The drivers all had the default set to FSYNC_SAFE.

2. It DOES scale the way it claims. It just doesn't have unlimited scalability and guess what no product does.

Re: PostgreSQL 9.4 Released

#128

Post by threeseed »

norkakn wrote: post #122
digitalzombie wrote: post #22

Earlier quoted context omitted.

How do you cluster in postgresql? Serious question, my prefer noSQL is cassandra and clustering is pretty easy. I ask this question every year and postgresql have not deliver this. If there is any, there are hardly any documentation on it.

Clustering is really, really hard. Cassandra is one of the better ones out there, but you have to deal with its data model and weird consistency promises (which however weird you think they are, are weirder) The correct way to cluster also changes dramatically depending on your use case. Sure there are things like RAC that promise to make it just work, but those don't scale more than a few nodes. Mongo is kind of the…

> Cassandra is one of the better ones out there

I take it you haven't actually used Cassandra much in the last few years. It's data model is almost identical to a typical relational one and it's consistency promises are quite clear:

http://www.datastax.com/documentation/cql/3.0/cql/aboutCQL.h...

And I've scaled Cassandra clusters from 1 to 100 nodes in hours with no issues. It really is quite simple. Likewise have had no issues with MongoDB replica sets. It is definitely not "really, really hard".

> postgres is to do it right, or not do it

What a pathetic cop out. PostgreSQL has been around for decades they've had plenty of time to have a proven, stable solution implemented.

Re: PostgreSQL 9.4 Released

#129

Post by petercooper »

VieElm wrote: post #55
petercooper wrote: post #45

Are there any good books coming out that cover Postgres 9.4? I know the docs are okay but I want something with more of a narrative structure as my history with Postgres is spotty. The only one I've found so far is O'Reilly's "PostgreSQL: Up and Running, 2nd Edition" coming out this month but would prefer a personal rec.

I have O'Reilly's "PostgreSQL: Up and Running, 2nd Edition" (You can buy the ebook already) and it's mostly about setting it up and administering postgres and a look at the tools around postgres. It's not a book that goes in depth on actually on how to write SQL for postgres, although it has a secton on this, or develop applications with postgres. It's more of an ops book. Anyway, I like it because coming from MySQL…

Thanks to Safari, I'm now several chapters into the book and it's perfect for me - thanks :) It was the ops side of things that was the biggest sticking point for me, although it seems like it'll dig into the JSONB stuff later on too.

Re: PostgreSQL 9.4 Released

#130

Post by davidgerard »

Postgres is about to be the new hotness. I mentioned to our hosting provider that we were looking into moving our in-house Oracle and MySQL to Postgres (off Oracle because it's expensive, off MySQL 'cos it's shit) and he said more than a few customers were looking into this precise move.

We're just getting into PG now, and it's just really nice to set up and use. I really wish more web stuff properly supported PG and didn't pretty much require MySQL.

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