Take the 2-minute tour ×
Database Administrators Stack Exchange is a question and answer site for database professionals who wish to improve their database skills and learn from others in the community. It's 100% free, no registration required.

Or in other words ... . Does the DBMS somehow circumvent the OS Cache manager and acccess the memory directly OR it lets the OS do its job, behave as a normal process and use the concept of virtual memory?

share|improve this question
add comment

1 Answer

up vote 4 down vote accepted

Virtual Memory is an indirection mechanism that map virtual addresses to physical addresses and the translation occurs in hardware layer through PTEs. A process can refer and address only virtual memory. Only privileged execution (kernel) can address physical memory. I recommend you read a book on the subject, the classic being Windows Internals by Russinovich/Solomon.

Your explanation is asking though a completely different question, whether OS 'Caches Manager' is circumvented. Virtual Memory is not a cache and there is never any sort of 'caching' in any discussion of a memory manager architecture (on any OS). It is not clear what 'cache manager' are you referring to. Does SQL Server do buffered IO (ie. uses OS file cache)? Generally no, see How It Works: Bob Dorr's SQL Server I/O Presentation.

share|improve this answer
    
Thanks! I will have to look more into it. I have obviously mixed two different things together. –  Ondra Peterka May 31 '13 at 14:25
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.