Re: compiling, performance of PostGreSQL 8.3 on 64-bit processors

On Thu, 26 Jun 2008, Adam Rich wrote:

> 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?

If you have more than 3GB of memory, you should be using a 64-bit OS.
While theoretically the 32-bit code might be smaller which has some
advantages, in practice the 64-bit versions will be faster.

> 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)

Much larger values for shared_buffers and work_mem seem to be the most
effective way to use larger amounts of memory.  For example, if you've got
1GB of RAM, it can be hard to allocate >15% of it to shared_buffers while
leaving enough enough RAM for OS-level operations, applications, etc.
But if you've got 16GB, a large read-only database might usefully set that
to 50% of RAM instead.

> 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 is a plain SQL dump, it's just a program to make it easier to
generate them.  You need to do this sort of dump/reload in order to
convert from a 32-bit to a 64-bit platform.

--
* Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD