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New Features Coming in PostgreSQL 10

rhaas.blogspot.com

11–20 of 138 posts

Re: New Features Coming in PostgreSQL 10

#11

Dumb question: does declarative partitioning pave the way for native sharding in Postgres? I'm not super super familiar, but it seems like along with some other features coming in Postgres 10, like parallel queries and logical replication, that this is eventually the goal.

I hope that it will have that effect. We need a few other features first: partitionwise join, partitionwise aggregate, asynchronous query, and ideally hash partitioning.

Re: New Features Coming in PostgreSQL 10

#12
post #11

Dumb question: does declarative partitioning pave the way for native sharding in Postgres? I'm not super super familiar, but it seems like along with some other features coming in Postgres 10, like parallel queries and logical replication, that this is eventually the goal.

I hope that it will have that effect. We need a few other features first: partitionwise join, partitionwise aggregate, asynchronous query, and ideally hash partitioning.

I see -- thanks! Really cool stuff.

Re: New Features Coming in PostgreSQL 10

#14

Extended Statistics! I was following the replication changes, but have just discovered the extended statistics and am more excited about them. The directory renaming at the bottom of the post is interesting - I wonder if many other projects have to do things like this?

> The directory renaming at the bottom of the post is interesting - I wonder if many other projects have to do things like this?

The background is that, over the years, a number of people deleted the pg_xlog and pg_clog directories when they noticed they're running out of space, thinking it's just server logs. Unfortunately that's the directories containing the database journal, and transaction status (committed/aborted/in-progress). Which means they'll loose data. The idea is to rename them to something that's less likely to be mistaken for unimportant data.

Re: New Features Coming in PostgreSQL 10

#15
I did read the article, but I can't find any mention of addressing the "Write amplification" issue as described by Uber when they moved away from postgres. https://eng.uber.com/mysql-migration/ I had heard talk on Software Engineering Daily that this new major revision was supposed to address that.

Is this issue resolved by the new "Logical replication" feature? It doesn't seem directly related, but it seems like maybe that is what he is referring to in this blog post?

Re: New Features Coming in PostgreSQL 10

#16

Impressive feature list. Glad to see logical replication is finally making it in.

What is you use case for it? My only thought was sending just one table to replica to be used to do analytics on ..

Isn't analytics a massive usecase in itself?

Re: New Features Coming in PostgreSQL 10

#17
For analytical loads the following is going to be great:

  While PostgreSQL 9.6 offers parallel query, this feature 
  has been significantly improved in PostgreSQL 10, with new 
  features like Parallel Bitmap Heap Scan, Parallel Index 
  Scan, and others.  Speedups of 2-4x are common with 
  parallel query, and these enhancements should allow those 
  speedups to happen for a wider variety of queries.

Re: New Features Coming in PostgreSQL 10

#18
post #15

I did read the article, but I can't find any mention of addressing the "Write amplification" issue as described by Uber when they moved away from postgres. https://eng.uber.com/mysql-migration/ I had heard talk on Software Engineering Daily that this new major revision was supposed to address that. Is this issue resolved by the new "Logical replication" feature? It doesn't seem directly related, but it seems like may…

There's a patch reducing write amplifications (when caused by indexes), by a significant degree. Unfortunately it didn't quite get ready in time for the feature freeze of 10 - as it affects the on-disk format, we considered the risk to be too high.

Re: New Features Coming in PostgreSQL 10

#19

Impressive feature list. Glad to see logical replication is finally making it in.

What is you use case for it? My only thought was sending just one table to replica to be used to do analytics on ..

Replication across major versions, for example to upgrade without downtime. Partial replication, to distribute shared data across a series of clusters, or for analytics and reporting as you mention. Replicating the data without replicating any table bloat. Being able to do limited writes (e.g. to temporary tables) on the standby. http://rhaas.blogspot.com/2011/02/case-for-logical-replicati...

Re: New Features Coming in PostgreSQL 10

#20

This is great because I couldn't go to production with earlier releases of logical decoding. Now we don't have to depend on a third party add on!

We're currently experimenting with logical decoding in 9.6, so I'd be curious to hear what problems you've been running into.
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