Are you sure you want to use MMAP in your database management system? [pdf]

Re:Are you sure you want to use MMAP in your database manage... by jstimpfle on Tuesday January 18, 2022 @10:15AM (#29980367)

Dude, the example I gave you with shm_open() is creating anonymous memory. That's just what non-file-backed mappings are called, no matter how long you want to keep obsessing about any "file paths".

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Re:Are you sure you want to use MMAP in your database manage... by CyberDildonics on Tuesday January 18, 2022 @10:42AM (#29980772)

This doesn't even seem like a reply to what I said.

If you map memory anonymously you aren't doing interprocess communication.

If you don't, you have a file path that the other program can use to map the same memory.

That's it, there is nothing wrong with this. I don't know why this is so upsetting. Mapping memory anonymously is local to the process tree and doesn't work for two different programs communicating.

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Re:Are you sure you want to use MMAP in your database manage... by jstimpfle on Tuesday January 18, 2022 @11:15AM (#29981347)

Ok, I'm extremely embarassed but it looks like I got the terminology wrong with regards to "Anonymous memory". And sorry for being so upset, at least I finally got something out of it.

It's also a fact that if I'm using disk swap space on a Unix, the same performance and stability issues apply as for disk backed file mappings. In that sense, there really is no difference.

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