Re: Review: query result history in psql

I just applied the patch to a clean branch from the latest master. I
couldn't get a segfault from using the new feature. Could you provide a
little more info to reproduce the segfault? Thanks

On Thu, Jun 27, 2013 at 11:28 PM, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>wrote:

> Hello
>
> after patching I god segfault
>
> Program terminated with signal 11, Segmentation fault.
> #0 0x0805aab4 in get_prompt (status=PROMPT_READY) at prompt.c:98
> 98 for (p = prompt_string;
> Missing separate debuginfos, use: debuginfo-install glibc-2.13-2.i686
> ncurses-libs-5.7-9.20100703.fc14.i686 readline-6.1-2.fc14.i386
> (gdb) bt
> #0 0x0805aab4 in get_prompt (status=PROMPT_READY) at prompt.c:98
> #1 0x0805786a in MainLoop (source=0xc45440) at mainloop.c:134
> #2 0x0805a68d in main (argc=2, argv=0xbfcf2894) at startup.c:336
>
> Regards
>
> Pavel Stehule
>
> 2013/6/28 ian link <ian(at)ilink(dot)io>:
> >> It's better to post a review as a reply to the message which contains
> >> the patch.
> >
> > Sorry about that, I did not have the email in my inbox and couldn't
> figure
> > out how to use the old message ID to send a reply. Here is the thread:
> >
> http://www.postgresql.org/message-id/flat/CAEcSYXJRi++T3pevDyzAWH2yGx7kG9ZrhX8KAWtP1fXV3H02vw(at)mail(dot)gmail(dot)com#CAEcSYXJRi++T3pevDyzAWH2yGx7kG9ZrhX8KAWtP1fXV3H02vw@mail.gmail.com
> >
> >> The 'EscapeForCopy' was meant to mean 'Escape string in a format require
> >> by the COPY TEXT format', so 'copy' in the name refers to the escaping
> >> format, not the action performed by the function.
> >
> >
> > I see, that makes sense now. Keep it as you see fit, it's not a big deal
> in
> > my opinion.
> >
> >> Some mathematical toolkits, like Matlab or Mathematica, automatically
> set
> >> a variable called 'ans' (short for "answer") containing the result of
> the
> >> last operation. I was trying to emulate exactly this behaviour.
> >
> >
> > I've actually been using Matlab lately, which must be why the name made
> > sense to me intuitively. I don't know if this is the best name, however.
> It
> > kind of assumes that our users use Matlab/Octave/Mathematica. Maybe
> 'qhist'
> > or 'hist' or something?
> >
> >> The history is not erased. The history is always stored in the client's
> >> memory.
> >
> > Ah, I did not pick up on that. Thank you for explaining it! That's
> actually
> > a very neat way of doing it. Sorry I did not realize that at first.
> >
> >> I was considering such a behaviour. But since the feature is turned off
> by
> >> default, I decided that whoever is using it, is aware of cost. Instead
> of
> >> truncating the history automatically (which could lead to a nasty
> surprise),
> >> I decided to equip the user with \ansclean , a command erasing the
> history.
> >> I believe that it is better to let the user decide when history should
> be
> >> erased, instead of doing it automatically.
> >
> >
> > I think you are correct. However, if we turn on the feature by default
> (at
> > some point in the future) the discussion should probably be re-visited.
> >
> >> This is my first submitted patch, so I can't really comment on the
> >> process. But if you could add the author's email to CC, the message
> would be
> >> much easier to spot. I replied after two days only because I missed the
> >> message in the flood of other pgsql-hacker messages. I think I need to
> scan
> >> the list more carefully...
> >
> > My fault, I definitely should have CC'd you.
> >
> > As for the patch, I made a new version of the latest one you provided in
> the
> > original thread. Let me know if anything breaks, but it compiles fine on
> my
> > box. Thanks for the feedback!
> >
> > Ian
> >
> >
> > --
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