David E. Wheeler wrote:
On Jun 5, 2008, at 14:47, Greg Smith wrote:
This is why there's the emphasis on preserving comments as they pass
into the GUC structure and back to an output file. This is one of the
implementation details I haven't fully made up my mind on: how to
clearly label user comments in the postgresql.conf to distinguish them
from verbose ones added to the file. I have no intention of letting
manual user edits go away; what I'm trying to do here (and this part
is much more me than Josh) is make them more uniform such that they
can co-exist with machine edits without either stomping on the other.
Right now doing that is difficult, because it's impossible to tell the
default comments from the ones the users added and the current comment
structure bleeds onto the same lines as the settings.
How about a simple rule, such as that machine-generated comments start
with "##", while user comments start with just "#"? I think that I've
seen such a rule used before. At any rate, I think that, unless you have
some sort of line marker for machine-generated comments, there will be
no way to tell them apart from user comments.
What comments do we consider machine-generated? Just the ones used to
comment out settings, like
#shared_buffers = 32MB
or something else?
If the automatic tool lets alone all other kind of comments, I think
we're fine. In fact, it wouldn't necessarily need to modify those
comments either, it could simply add a new setting line below that:
#shared_buffers = 32MB
shared_buffers = 1024MB
For extra safety, it could comment out old settings, perhaps with
something like this:
#shared_buffers = 32MB
#shared_buffers = 1024MB # commented out by wizard on 2008-06-05
shared_buffers = 2048MB
This would preserve a full change history in the file. It would become
quite messy after a lo of changes, of course, but a user can trim the
history by hand if he wants to.
Or perhaps we should explicitly mark the settings the tool has
generated, and comment out:
#shared_buffers = 32MB # commented out by wizard on 2008-06-05
shared_buffers = 1024MB # automatically set by wizard on 2008-06-05
That way the tool could safely replace automatically set settings,
without replacing manually set ones without leaving a clear trace of
what happened.
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
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