On Mon, 2008-02-04 at 18:08 -0300, Alvaro Herrera wrote: > Simon Riggs wrote: > > On Mon, 2008-02-04 at 20:03 +0000, Gregory Stark wrote: > > > > > I wonder how hard it would be to shove the clog into regular shared > > > memory pages and let the clock sweep take care of adjusting the > > > percentage of shared mem allocated to the clog versus data pages. > > > > There is a reason that's not been done... try it and see. > > What is it?
Time to locate a block differs in the two cases. clog requires a search of data on 1 cache line, which isn't often changed. shared_buffers requires a hash table search on a volatile data structure. -- Simon Riggs 2ndQuadrant http://www.2ndQuadrant.com ---------------------------(end of broadcast)--------------------------- TIP 7: You can help support the PostgreSQL project by donating at http://www.postgresql.org/about/donate
