Simon Riggs <simon@2ndquadrant.com> writes:
> ... I'm looking into PostgreSQL on small
> handheld devices. Clearly these have limited memory and little "disk"
> capability...
> Are there some ports available to various devices?
I don't know of any supported ports.
> What is the lowest memory footprint PostgreSQL has achieved?
This depends entirely on your postgresql.conf settings and how complex
the queries you want to process are. I would think you could get it
down to maybe 4 or so meg if you have bottom-of-the-barrel requirements.
Performance in this configuration not guaranteed ;-)
> How little disk space has anyone achieved?
> Is that an available port, or just a set of configure options?
IIRC, configuring the WAL segment size is a pg_config_manual.h setting
in CVS tip, but in extant releases you'd have to dig into the xlog code
to adjust it.
> Q: Does PostgreSQL write repeatedly even when there is a no overt SQL
> write activity?
Given a SELECT-only query load, I'd expect PG to reach a state of zero
new writes fairly quickly (at the latest, after a vacuum and checkpoint
have occurred). The real problem is that any single update operation
will generate quite a number of disk writes, the more so the smaller
your shared_buffers setting :-(. It's not at all optimized to minimize
writes in a low-but-not-zero-update-traffic situation. So you'd likely
be facing some issues with FLASH lifetime.
regards, tom lane