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Postgresql 9.6: Support parallel aggregation

postgresql.org

11–20 of 64 posts

Re: Postgresql 9.6: Support parallel aggregation

#12

There is going to come a point where Postgres passes Oracle in terms of features and performance. There is also a point that Postgres will perform with enough features needed by most businesses that they'll choose it even though it doesn't match Oracle on a feature by feature basis. We have hit peak Oracle. From this point forward it's going to be hard for Oracle to regain momentum. Expect a lot of FUD against Postgr…

Oracle is writing Russian IT shops to try and convince them from moving to postgres http://www.postgresql.org/message-id/CANNMO++6tPiwBv2OKcy-Hh...

Re: Postgresql 9.6: Support parallel aggregation

#13

Blog post with some details and benchmarks by one of the authors of the patch: http://rhaas.blogspot.com/2015/11/parallel-sequential-scan-i...

That's not about parallel aggregate but about parallel scan.

Also, Robert is not the author of the patch, he did a review and committed it. The actual author are listed in the commit message: David Rowley and Haribabu Kommi.

Re: Postgresql 9.6: Support parallel aggregation

#14
post #6
post #5

I would love to see some sample benchmarks for the type of gains you might see from this. I always see these interesting new PostgreSQL features being posted, and they sound cool, but it's hard to know how much they help in practice. I understand it's often highly workload and data dependent, but something would be better than nothing.

It would help a lot for typical data warehouse queries that involves aggregating millions to billions of rows. SELECT EXPLAIN ANALYZE will tell if its relevant for you ;-)

> SELECT EXPLAIN ANALYZE will tell if its relevant for you

That assumes I run PostgreSQL already, which I don't. I am interested in possibly switching at some point if it's worthwhile, but it's hard to muster the effort to do concerted testing of a representative sample of my data, including possibly changing how queries are done to take advantage of specific features, when I have little information to go on.

Not that I expect PostreSQL to do in-depth analysis of everything, but it would be great from both a promotional and technical standpoint if there was something like "we've seen something like X% speedup of queries utilizing Y, and up to Z% speedup in extreme cases." I mean, I assume they at least have rudimentary numbers for this, otherwise they would be making blind changes without knowing whether it improved or degraded performance. Providing just enough to get people interested in doing their own benchmarking (and possibly publishing them) would be great for everyone.

Edit: One of top comment is actually what I'm talking about (but apparently for a different feature). So it does get done, which is really nice. :)

Edit2: Now there's the link to the blog post for this feature. :)

Re: Postgresql 9.6: Support parallel aggregation

#15

Short of doing a deep dive into Postgresql, do any universities use Postgresql as a basis for their DB implementation courses? I wanted to dive into Postgres and was hoping for some training wheels. Thanks.

Dive in the documentation + mailing list + postgresql planet.

Re: Postgresql 9.6: Support parallel aggregation

#17

There is going to come a point where Postgres passes Oracle in terms of features and performance. There is also a point that Postgres will perform with enough features needed by most businesses that they'll choose it even though it doesn't match Oracle on a feature by feature basis. We have hit peak Oracle. From this point forward it's going to be hard for Oracle to regain momentum. Expect a lot of FUD against Postgr…

> There is going to come a point where Postgres passes Oracle in terms of features and performance.

I wouldn't be so sure. Oracle has deep pockets, and I'm not sure there's a reason why anything PostgreSQL wants to roll out they can't pay to prioritize and have done sooner.

> There is also a point that Postgres will perform with enough features needed by most businesses that they'll choose it even though it doesn't match Oracle on a feature by feature basis.

No argument there.

Re: Postgresql 9.6: Support parallel aggregation

#18
post #5

I would love to see some sample benchmarks for the type of gains you might see from this. I always see these interesting new PostgreSQL features being posted, and they sound cool, but it's hard to know how much they help in practice. I understand it's often highly workload and data dependent, but something would be better than nothing.

David Dowley (one of the authors of the patch) posted some measurements on TPC-H Q1: https://news.ycombinator.com/item?id=11332713

The machine has 4x E5-4620, so 32 physical cores. And with 30 workers it gets ~80% of the theoretical speedup. Not bad, I guess.

Re: Postgresql 9.6: Support parallel aggregation

#19

Short of doing a deep dive into Postgresql, do any universities use Postgresql as a basis for their DB implementation courses? I wanted to dive into Postgres and was hoping for some training wheels. Thanks.

PG is, IMHO, probably one of the best code bases for this.

I'm far and away not a database hacker, but have read parts of the code at various times to better understand what I was seeing. The codebase is incredibly well written and organized, and the documentation (both developer and user) is top-notch.

The only problem I can think of with using it in a course would be choosing what to focus on with only a semester. Add in the long revision history and I think there are also multiple theses in there on the sociology of open source.

Re: Postgresql 9.6: Support parallel aggregation

#20
post #17

There is going to come a point where Postgres passes Oracle in terms of features and performance. There is also a point that Postgres will perform with enough features needed by most businesses that they'll choose it even though it doesn't match Oracle on a feature by feature basis. We have hit peak Oracle. From this point forward it's going to be hard for Oracle to regain momentum. Expect a lot of FUD against Postgr…

> There is going to come a point where Postgres passes Oracle in terms of features and performance. I wouldn't be so sure. Oracle has deep pockets, and I'm not sure there's a reason why anything PostgreSQL wants to roll out they can't pay to prioritize and have done sooner. > There is also a point that Postgres will perform with enough features needed by most businesses that they'll choose it even though it doesn't m…

Oh, I'm not saying this is an overnight thing or that Oracle will be destroyed. In fact, I don't want to see them destroyed, but what I am interested in is that their market power and influence wanes over time. Ironically, this will be good for Oracle - they will be forced to dump immoral and illegal business practices.

The problem commercial businesses have when it comes to open source is that you might be able to reduce customer take up, by you can't compete with it like you would other businesses. In the closed source world you can purchase a company and shut down its product and thus kill off the competition.

As Microsoft have found, with open source software, that's not possible.

The other unfortunate thing for Oracle is that when they attack Postgres they have to publish lists of competitive advantages. All this does is give Postgres developers a todo list, and they then work towards implementing the features that matter.

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