A Study on Altering PostgreSQL from Multi-Processes Structure to   Multi-Threads Structure
  How to altering PostgreSQL database from multi-processes structure to multi-threads structure is a difficult problem. In the paper, we bring forward a comprehensive alteration scheme. Especially, put rational methods to account for three difficult points: semaphores, signal processing and global variables. At last, applied the scheme successfully to modify a famous open source DBMS. 
Zhiyong Shan
cs.DB