Re: psql - -dry-run option

2015-12-17 20:03 GMT+01:00 Tom Lane <tgl@sss.pgh.pa.us>:

Pavel Stehule <pavel.stehule@gmail.com> writes:
> when I read a blog
> http://www.depesz.com/2015/12/14/waiting-for-9-6-psql-support-multiple-c-and-f-options-and-allow-mixing-them/
> where is emulated dry-run mode, I though so we can implement it very
> simply.

Not one that is actually reliable.  All a script would have to do is
include its own begin/commit commands, and it would override what you
are talking about.  It's okay, in my opinion, if the -1 switch is just a
half-baked "best effort" solution.  It's not okay to provide a --dry-run
switch that is equally full of holes, because if someone were to actually
rely on it to not execute the script, the possibility of an override would
amount to a security bug.

My idea was enforce global transaction (-1) option and ensure STOP_ON_ERROR mode (cannot be changed later). Any inner COMMIT or ROLLBACK have to be disallowed (or ignored) - what can be problem :(

and if all statements from input stream was processed, then ROLLBACK is emitted, but result is success.

Pavel

 

                        regards, tom lane