Hi, Juan, Juan Casero (FL FLC) wrote: > Ok that is beginning to become clear to me. Now I need to determine if > this server is worth the investment for us. Maybe it is not a speed > daemon but to be honest the licensing costs of an SMP aware RDBMS is > outside our budget. When postgresql starts does it start up a super > server process and then forks copies of itself to handle incoming > requests? It starts a super server process (Postmaster) and some background processes (background writer, stats collector). For each incoming connection, the postmaster forks a single-threaded backend process, which handles all queries and transactions on this connection, and terminates when the connection terminates. So as a thumb-rule, each connection can utilize only a single CPU. You can utilize a few more CPUs than you have simultaneous connections, due to the background processes and the OS needing CPU for I/O, but thats rather marginal. AFAIK, Bizgres MPP has extended the backend processes to be multi threaded, so a single connection can utilize several CPUs for some types of queries (large data sets, sorting/joining/hashing etc.). Btw, I presume that they might offer you a free test license, and I also presume their license fee is much lower than Oracle or DB/2. > Or do I have to specify how many server processes should be > started up? You can limit the number of server processes by setting the maximum connection limit. > I figured maybe I can take advantage of the multiple cpu's > on this system by starting up enough postgres server processes to handle > large numbers of incoming connections. I have this server available for > sixty days so I may as well explore the performance of postgresql on it. Yes, you can take advantage if you have multiple clients (e. G. a wep app, that's what the T2000 / Niagara were made for). You have a Tomcat or Jboss sitting on it, each http connection forks its own thread. Each customer has its own CPU :-) Then use a connection pool to PostgreSQL, and you're fine. The more customers, the more CPUs are utilized. But beware, if you have floating point maths, it will be very slow. All 8 CPUs / 32 Threads share a single FPU. So if you need floating point (e. G. Mapserver, PostGIS geoprocessing, Java2D chart drawing or something), T2000 is not the right thing for you. HTH, Markus -- Markus Schaber | Logical Tracking&Tracing International AG Dipl. Inf. | Software Development GIS Fight against software patents in EU! www.ffii.org www.nosoftwarepatents.org
