[chx]

> For everybody with databases that are not that huge PostgreSQL will do just fine.

Ha. Remember Gary Bernhardt of WAT fame? https://twitter.com/garybernhardt/status/600783770925420546

> Consulting service: you bring your big data problems to me, I say "your data set fits in RAM", you pay me $10,000 for saving you $500,000.

[jiggawatts]

AWS will happily rent you a server with 24 TB of memory for about $200/hour.

Columnar databases typically get a 10:1 compression ratio over raw data = 240 TB effectively.

That’s a lot of data.

[RhodesianHunter]

Which columnar databases are doing the above in-memory?

[jiggawatts]

SQL Server supports in-memory columnstore tables. I’m not an expert but I suspect SAP HANA also.

If you squint, any database engine is “in memory” if there is more buffer than data.

Or just use a RAM disk!

[folmar]

> If you squint, any database engine is “in memory” if there is more buffer than data.

That is sadly not true, I remember one lonely night debugging a MSSQL 2012 instance that was _very_ slow, and it turned out that for a simple query (one join, 100 rows in one table and 10 in the other, 100 result in total, one where clause) it forced writing the result to disk before evaluating the WHERE condition. Unable to fight the scheduler I've ended up making a ramdisk for this data.

[jiggawatts]

Yes, tempdb spills can be annoying, but I believe they never occur for queries that use only in-memory tables.

[mianos]

Kdb with ease, but down 500k on licenses and the cost of people who can use it. :)