When I am creating basically empty databases (for ex. 20’000) each with 5 empty collections, stay these databases/collections all “open”/cached ? So that they will use more/override the WT cache settings ?
As an ex.
Total RAM = 8GB
WT Cache setting = 1GB
Used RAM by MongoDB ca. 7.5 GB
My expectation would be that due to the 1GB WT Cache the overall RAM usage would be much lower (I know 1GB is not suitable but just wanted to check out what is using RAM).
So could anyone explain how the databases and/or collections are handled regarding caching / memory usage ?