SQL Server database principles Reading Notes (I)-SQL Server Architecture

Sqlserver architecture: NetworkProgramLibrary, user-mode scheduler, relational engine, Ole database, storage engine, Io manager, WIN32API.

1. Update execution is divided into two situations::
1) direct replacement;

2) perform the delete and insert operations respectively;

2. The sqlserver page size is 8 K. Each 8 pages form a "set" (extent), which is the minimum unit for allocating space for recycling;

3. transactions are implemented by writing logs first;

4. transaction isolation levels include: non-committed read, committed read, Repeatable read, and serializable;

5. Share lock (read), exclusive lock (write), intention lock, Set lock, etc;

6. Three phases of data recovery: analysis, redo, and reverse;

7. can use fragmented I/O (that is, the eight page addresses of a set can be discontinuous ).