Re:Goodbye MongoDB, Hello PostgreSQL (2015)
by HelloNurse on Thursday March 11, 2021 @05:37AM
(#26422506)
Your data-saving test was probably limited by how fast you could save to disk a roughly equal amount of data with the two databases; queries might work and perform more differently.
Re:Goodbye MongoDB, Hello PostgreSQL (2015)
by amenod on Thursday March 11, 2021 @09:03AM
(#26424094)
That's what I meant by "no persistence needed". In both cases, I wasn't actually saving anything to disk. I needed an in-memory storage for a never-ending stream of incoming data that would be read (and purged) by a separate process, no biggie if the data got lost occasionally.
I also simply inserted and read the data, no complex queries or anything. Key-value store is all I needed and for this particular case PostgreSQL was as good at it as Redis.
Re:Goodbye MongoDB, Hello PostgreSQL (2015)
by kinos on Thursday March 11, 2021 @03:21PM
(#26428548)
Why did you use a database instead of just creating a global map and running in memory? Sharding?
No - different processes were reading and writing.
And once you implement a global map which is accessible from multiple processes, you might as well use an existing solution, like Redis. Or, as I've learned, pgSQL - which gave me the same performance with less moving parts (because I was already using it) when I disabled WAL.
This is anecdotal, of course, and it is possible that I simply didn't optimize Redis enough (though I did give it my best!). Let me also say that Redis is great otherwise, it was just in this specific case that PostgreSQL surprised me and fulfilled the need itself.