Thread: Understanding transactions
Seeing how PITR, nested transactions, and other exciting developments related to transactions are being developed, I am getting curious about how PostgreSQL actually implements transactions. Investigating Materialized Views has led me to look closely at how transactions work and such. Do you know of good resources on learning how transactions are implemented in PostgreSQL? Should I just peruse the code? Which files are most relevant? -- Jonathan Gardner jgardner@jonathangardner.net
On Thu, Jun 03, 2004 at 05:38:21PM -0700, Jonathan Gardner wrote: > Do you know of good resources on learning how transactions are implemented > in PostgreSQL? Should I just peruse the code? Which files are most > relevant? backend/access/transam/xact.c (high level transaction status) and backend/utils/time/tqual.c (low level tuple visibility test --- this is hard to read and understand) and its respective header files are the most relevant. See also htup.h about "heap tuples," specially heap tuple headers and the games with Xmin, Xmax, Cmin and Cmax. Not sure about other literature. Make sure you understand how MVCC works before reading the code ... -- Alvaro Herrera (<alvherre[a]dcc.uchile.cl>) Y dijo Dios: "Que sea Satanás, para que la gente no me culpe de todo a mí." "Y que hayan abogados, para que la gente no culpe de todo a Satanás"
Jonathan Gardner wrote: > Seeing how PITR, nested transactions, and other exciting developments > related to transactions are being developed, I am getting curious about how > PostgreSQL actually implements transactions. Investigating Materialized > Views has led me to look closely at how transactions work and such. > > Do you know of good resources on learning how transactions are implemented > in PostgreSQL? Should I just peruse the code? Which files are most > relevant? Next to diving into the code you might want to dive into the theory. Chapter 5 of "Concurrency Control and Recovery in Database Systems" deals with Multi Version Concurrency Control: http://research.microsoft.com/pubs/ccontrol/ Jochem