Shadow Paging (cont’d)
For page locking, you must lock each page table while updating its pointer and transferring to disk.
- Consider two transactions that updated different pages of the same file and are committing concurrently.
[Lorie, ACM Trans on DB Sys., March 77]
Used in the Gemstone OO DBMS.
Not good for TPC
- count disk updates per transaction
- how to do record level locking?