Thoughts on Uber’s List of Postgres Limitations • Hacker News Board

Re: Thoughts on Uber’s List of Postgres Limitations

#11

Post by taspeotis » Wed, Aug 03, 2016, 10:22 AM UTC

grabcocque wrote: post #6

'Error establishing database connection' How very meta.

Fortunately they can call themselves!

    WHEN IT'S CRITICAL, YOU CAN COUNT ON US
    2ndQuadrant provides full 24/7 problem resolution technical support for production systems.
    If PostgreSQL breaks, we'll get you back up quickly.

[1] https://2ndquadrant.com/en/support/support-postgresql/

Re: Thoughts on Uber’s List of Postgres Limitations

#12

Post by tehbeard » Wed, Aug 03, 2016, 10:30 AM UTC

Dowwie wrote: post #8

Does anyone know the back story to Uber - why didn't it try to improve Postgres rather than move on to feed on another host?

Most likely they don't have any engineers with the skills necessary to build/improve a RDBMS.

(note I said build, not use, different skillsets between driving a car and re-configuring the engine to run on seed oil)

Re: Thoughts on Uber’s List of Postgres Limitations

#13

Post by okket » Wed, Aug 03, 2016, 10:31 AM UTC

Dowwie wrote: post #8

Does anyone know the back story to Uber - why didn't it try to improve Postgres rather than move on to feed on another host?

Watch

https://vimeo.com/145842299

Re: Thoughts on Uber’s List of Postgres Limitations

#14

Post by leftnode » Wed, Aug 03, 2016, 10:38 AM UTC

Illniyar wrote: post #7

I think its worth mentioning again that what Uber ended up using has no resemblence to an RDBMS (single table, manual indexes). So regardless of whether their complaints are justified or not, it should not be taken as an endorsment of mySQL over postgres, but rather of an endorsement of NoSQL over RDBMS . Which is really just what every company at these scales do (except for google and f5 if whitepapers are to be con…

Can you expand on what you mean by a single table with manual indexes? How does a frequently used table with indexes not resemble an RDBMS?

Re: Thoughts on Uber’s List of Postgres Limitations

#15

Post by pwg » Wed, Aug 03, 2016, 10:50 AM UTC

Dowwie wrote: post #8

Does anyone know the back story to Uber - why didn't it try to improve Postgres rather than move on to feed on another host?

In one of the other HN threads on the issue, there was mention that the switch occurred shortly after a change in leadership position of individuals with enough 'power' to impart technology changes by decree. So there is an aspect that there was some, if not much, political opinion involved as there was any technical analysis involved in the change.

Given the fact that the change which occurred is an "apples to oranges comparison" change (PostgreSQL and an SQL normalized DB table structure to MySQL and a noSQL style single table key-value store) then there is some credence one can put towards the rumor that some (or most) of the change may have come about from a PHB [1] saying "do this, this way".

[1] PHB (Pointy Haired Boss, Dilbert cartoon reference)

Re: Thoughts on Uber’s List of Postgres Limitations

#16

Post by ssclafani » Wed, Aug 03, 2016, 10:53 AM UTC

Dowwie wrote: post #8

Does anyone know the back story to Uber - why didn't it try to improve Postgres rather than move on to feed on another host?

https://eng.uber.com/mysql-migration/

https://news.ycombinator.com/item?id=12201353

Re: Thoughts on Uber’s List of Postgres Limitations

#17

Post by fauigerzigerk » Wed, Aug 03, 2016, 10:57 AM UTC

Illniyar wrote: post #7

I think its worth mentioning again that what Uber ended up using has no resemblence to an RDBMS (single table, manual indexes). So regardless of whether their complaints are justified or not, it should not be taken as an endorsment of mySQL over postgres, but rather of an endorsement of NoSQL over RDBMS . Which is really just what every company at these scales do (except for google and f5 if whitepapers are to be con…

If it was just about NoSQL vs RDBMS they could have used Postgres as a key-value store instead of mySQL. So yes they absolutely did endorse mySQL over Postgres.

Also, what is the scale of Uber that you think is unsuitable for RDBMS? Uber does a million rides per day but these rides are very predictably local. I don't know enough to make any firm claims here but at first sight this doesn't look like the sort of scale that is unachievable on an RDBMS in principle.

Re: Thoughts on Uber’s List of Postgres Limitations

#18

Post by Illniyar » Wed, Aug 03, 2016, 11:08 AM UTC

leftnode wrote: post #14

Illniyar wrote: post #7

I think its worth mentioning again that what Uber ended up using has no resemblence to an RDBMS (single table, manual indexes). So regardless of whether their complaints are justified or not, it should not be taken as an endorsment of mySQL over postgres, but rather of an endorsement of NoSQL over RDBMS . Which is really just what every company at these scales do (except for google and f5 if whitepapers are to be con…

Can you expand on what you mean by a single table with manual indexes? How does a frequently used table with indexes not resemble an RDBMS?

the secondary indexes are saved in a different table and (I can only assume) the application layer (or one layer above mySql) is responsible for keeping that table up to date.

If you use only 1 table, then it's by no means "relational", so I don't see why you'll need a database system designed from start to finish to support a relational model.

Re: Thoughts on Uber’s List of Postgres Limitations

#19

Post by eyan » Wed, Aug 03, 2016, 11:11 AM UTC

f055 wrote: post #10

I came here to write a snarky comment, but now I can write two ;) first: if you think any particular db platform is clearly a winner in "db wars", you are naive. there are so many factors involved in configuring the db, the backend, the frontend etc. that you can always find a case where: the supposedly winning db is failing, or the supposedly worse db is performing perfectly fine. and from my experience, you should…

I came here to thank the Postgres developers for their hard work. Also their grace under such trying times.

Re: Thoughts on Uber’s List of Postgres Limitations

#20

Post by mranney » Wed, Aug 03, 2016, 11:28 AM UTC

Illniyar wrote: post #7

I think its worth mentioning again that what Uber ended up using has no resemblence to an RDBMS (single table, manual indexes). So regardless of whether their complaints are justified or not, it should not be taken as an endorsment of mySQL over postgres, but rather of an endorsement of NoSQL over RDBMS . Which is really just what every company at these scales do (except for google and f5 if whitepapers are to be con…

Uber runs a lot of databases in production. We stopped using Postgres a while ago for new applications that talk SQL, and this article explains some of the reasoning.

We still have many applications that talk directly to MySQL, and we still have our original API monolith that talks directly to Postgres.

All new applications are being built using distributed databases like our in-house Schemaless system which happens to be backed by MySQL, and we also have Riak and Cassandra in production.