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The whole point of a DB is to remember the data after power cycle. So either way you turn it both solutions go to disk?
by bullen 3y ago
The whole point of a DB is to remember the data after power cycle.
So either way you turn it both solutions go to disk?
- avianlyric 3y agoSure, querying that data is also important. Which means the question of “do you optimise for in-memory queries, or on disk queries” is important. Simply saying you want the data to be durable isn’t that interesting or hard to achieve, there’s plenty of ways of achieving durable storage. The hard part is doing durable storage while also solving problems like query speed, and concurrency control.
- Guvante 3y agoIt depends on what you mean by durable. Claiming that persistence to disk is trivial when compared to returned values is a stretch IMHO. Modern DBs still have bugs where data returned is different than permanently persisted leading to inconsistency errors. And that is ignoring performance queries that don't require any guarantees.
- avianlyric 3y agoUnless you’re writing directly to a flat file, and basically storing a direct representation of your data on disk, as it exists in your application. Then your DB is doing something to improve the performance of your queries, whether that indexes, or other clever on-disk structures, it exists only to improve query performance.
- CyberDildonics 3y agoThe whole point of a DB is to remember the data after power cycle. You are thinking of a file system.
- DaiPlusPlus 3y agoDatabases don’t have to use a file-system - look at old Big Iron systems where the database is the file-system. In the context of Linux/Unix/etc, the file-system is just another API for the OS - consider /dev/null or /proc - those are certainly in the file-system but they aren’t tied to persistent storage.
- CyberDildonics 3y agoDatabases don’t have to use a file-system I didn't say they did. consider /dev/null or /proc - those are certainly in the file-system but they aren’t tied to persistent storage. I'm not sure what point you're trying to make here.
- DaiPlusPlus 3y agoMy point is that no definition of the term “file-system” makes any guarantees about persistence, whereas I interpreted your post saying this: > > The whole point of a DB is to remember the data after power cycle. > You are thinking of a file system. …as though you’re saying only an FS can persist data.
- CyberDildonics 3y agoNo, I'm saying that persisting data is mainly what a filesystem is about unless you go into some pedantic nonsense trying to tear apart a general statement.
- DaiPlusPlus 3y agoOkay, let’s just agree to disagree then.
- CyberDildonics 3y agoThis is like someone saying memory is about storing data while the computer is on and someone else trying to start an argument by saying that sometimes memory addresses are used to communicate with video cards.