Re: Which sourcefiles needed?

Dick Kniep wrote:
> Op do 24-04-2003, om 14:53 schreef Gerhard Haering:
> 
>>Dick Kniep wrote:
>>
>>>Hi list,
>>>
>>>We are developing a system with a central database and many clients. The
>>>server and all clients run Linux. The database runs on the central
>>>server (surprise, surprise). To run pyPgSQL on the clients, we need to
>>>install it on all clients (is that so?), but to compile it (on the
>>>client), it needs Postgresql files. My question is which files are
>>>needed, and where should I locate them...
>>
>>I can't tell which files exactly are needed to build against 
>>PostgreSQL's libpq. Building pyPgSQL works best if you have the 
>>PostgreSQL header and libraries installed (and not just in a PostgreSQL 
>>source tree). For most Linux distributions, there are several PostgreSQL 
>>packages, in particular you'll need the development package.
>> [...]
>>The correct paths should be picked up by setup.py automatically for most 
>>major distributions (Debian, SuSE, Redhat). If not, you'll have to fire 
>>up an editor with setup.py and
>>
>>- set USE_CUSTOM = 1
>>- set include_dirs and library_dirs appropriately

> Thanks for the advice, I am using Slackware, which is a bit different
> from Redhat and others. I see 3 alternatives:
> 
> - Compile on the server and also RUN on the server, in which case I will
> have to adjust the PYTHONPATH on the client (is that the only required
> change?? and is it performing??)

You mean using pyPgSQL via a remote directory mounted via NFS? Sure 
that's possible. Performance isn't a problem - the import of the pyPgSQL 
module is a little slower but after the import Python doesn't care where 
the module came from.

> - Compile on the server (which has all files naturally) and distribute
> libpq etc. to the clients

You'd only need to distribute libpq.so.$version to the clients. I'd try 
to statically link against libpq, though. This saves you distribution 
the libpq shared library.

> - Compile on the clients after installing Postgresql completely (Ugly)

That's what you get for Slackware's nonexis^wprimitive package 
management :-P I use a similar one on FreeBSD and haven't found it a 
problem, though. Just don't start the PostgreSQL server when you don't 
need it. It'll waste some disk space, but that's all :-)

> Both from a performance and maintainance point of view I would prefer
> the first option, but do not know exactly how to go about it.

Do you have any software distribution system in place?

If not here's my recommended way:

- compile pyPgSQL statically against libpq
- tar-gz the pyPgSQL build directory up
- un-tar-gz it on the client
- python setup.py install

The ideal way would be to package pyPgSQL for Slackware (it's already 
packaged at least for FreeBSD, RPM- and .deb-based systems).

> Maintainance off course because there is only one installation of the
> package, which is always easier to maintain.
> I think it is also on the performance side the best option, as it
> processes all actual I/O and conversion on the server, and passes only
> the results back to the client, only the actual import of the package
> requires extra network traffic.

I don't understand this paragraph, but could it be you're having a logic 
error there? Just because pyPgSQL is imported from a network share 
doesn't mean the work will actually be done on the network server?!

I don't want to sound like the wise guy (don't have that much experience 
administering Unix), but I'd recommend you get *some* software 
distribution system in place if you have several machines. If you 
already have your software in a packaged form, that's not an issue, just 
set up a repository where the clients can download and install their 
.deb/.rpm/.pkg whatever. For Slackware, something like rdist over ssh 
might be a simple, yet powerful option.

Just mounting the "local software" repository via NFS and setting paths 
appropriately is another simple alternative.

-- Gerhard


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