On Thu, Jun 26, 2008 at 7:12 PM, Adam Rich <adam.r@xxxxxxxxxxxxx> wrote: > >> 1. I have heard of problems arising from compiling PostGreSQL (8.3) on >> 64-bit >> processors. What sort of problems am I likely to encounter and how >> should I fix >> them? We are will run Linux Redhat 5 on a Dell PE2950 III Quad Core >> Xeon E54 >> 2.33 GHz, and a Dell PE2950 III Quad Core Xeon L5335 2.0 GHz. >> >> 2. Are there performance problems running PostGreSQL 8.3 on a 64-bit >> processor? Should compile and run fine--I haven't heard of any problems with it, and PG has run on 64-bit systems (SGI, Sun, Alpha) long before there was x86_64. > I have a few more questions on the 64-bit topic. Is there any benefit > to running a 32-bit OS (rhel 5 in this case) on a server with more than > 4 GB of memory? In other words, can the OS-level cache take advantage > of more than 4 GB of memory? With a 32-bit kernel and >4GB of memory, you will indeed get more available to cache from the OS. It's generally not recommended to use more than 8GB with a 32-bit kernel. > Can a process (such as PG backend) use > more than 4 GB of shared memory on a 32-bit OS? No, and the practical limit is more like 2GB (or less). >Or is the 4 GB memory > point the place where you normally transition to a 64-bit OS? In this day and age there's not too much of a reason to run in 32 bits on a server capable of 64. If necessary, you can run 32-bit legacy binaries under a 64-bit kernel, if you set up the libraries properly. > For people with experience running postgresql on systems with 16+ GB > of memory, what parameter settings have you found to be effective? > (This would be a large database that's mostly read-only that we'd > like to fit completely in memory) Can't help with this one, sorry. > Is it possible to backup (pg_dump) from a 32-bit OS to a 64-bit OS, > or is a plain SQL dump necessary? pg_dump output (which by default *is* plain SQL, though there are two other formats) is compatible across architectures. Backups of the on-disk database files are not. -Doug
