Martin Pitt <martin (AT) piware (DOT) de> writes:
Well, more generally what we need is a better match algorithm in
make_relative_path. After a few moment's thought I propose:

* Determine the common prefix of the compiled-in target_path and
bin_path (for typical cases this would be "/usr" or "/usr/local";
worst case is that the common prefix is just "/"). Call everything
to the right of the common prefix the "tail" of these paths. The
currently expected scenario is that the tails are "share" and "bin",
but there might be more than one directory level in them.

* Try to match the tail of the bin_path to the end of the actual binary
location (my_exec_path without the executable's name).

* If match, take everything to the left of the match in my_exec_path,
and append the tail of target_path to produce the result.

* If no match, use target_path as-is, same as now.

I think this would get right all of the cases the current code gets
right, and more generally would work when we need to substitute N
levels of directory names instead of just one. It may still be a
few bricks shy of a load, however. Any thoughts?

regards, tom lane

---------------------------(end of broadcast)---------------------------
TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match