Thread: Another little thing about psql wrapped expanded output
regression=# \pset format wrapped Output format is wrapped. regression=# \x Expanded display is on. regression=# select * from int8_tbl; -[ RECORD 1 ]------------------------------------------------------------------- q1 | 123 q2 | 456 -[ RECORD 2 ]------------------------------------------------------------------- q1 | 123 q2 | 4567890123456789 -[ RECORD 3 ]------------------------------------------------------------------- q1 | 4567890123456789 q2 | 123 -[ RECORD 4 ]------------------------------------------------------------------- q1 | 4567890123456789 q2 | 4567890123456789 -[ RECORD 5 ]------------------------------------------------------------------- q1 | 4567890123456789 q2 | -4567890123456789 Notice that the dashed lines go all the way to the right margin of my 80-column terminal window, even though the data requires no more than 22 columns. While this doesn't look so awful as-is, when I'm working in a very wide window it starts to look a little silly. The behavior I'd have expected is that if the data is narrower than the window, the lines only go to the right margin of the data. This is a trivial change to the logic in print_aligned_vertical, but before I go make it, does anyone want to argue that the current behavior is preferable to that? regards, tom lane
On Tue, Dec 01, 2015 at 11:20:53AM -0500, Tom Lane wrote: > regression=# \pset format wrapped > Output format is wrapped. > regression=# \x > Expanded display is on. > regression=# select * from int8_tbl; > -[ RECORD 1 ]------------------------------------------------------------------- > q1 | 123 > q2 | 456 > -[ RECORD 2 ]------------------------------------------------------------------- > q1 | 123 > q2 | 4567890123456789 > -[ RECORD 3 ]------------------------------------------------------------------- > q1 | 4567890123456789 > q2 | 123 > -[ RECORD 4 ]------------------------------------------------------------------- > q1 | 4567890123456789 > q2 | 4567890123456789 > -[ RECORD 5 ]------------------------------------------------------------------- > q1 | 4567890123456789 > q2 | -4567890123456789 > > Notice that the dashed lines go all the way to the right margin of my > 80-column terminal window, even though the data requires no more than > 22 columns. While this doesn't look so awful as-is, when I'm working > in a very wide window it starts to look a little silly. > > The behavior I'd have expected is that if the data is narrower than > the window, the lines only go to the right margin of the data. This > is a trivial change to the logic in print_aligned_vertical, but before > I go make it, does anyone want to argue that the current behavior is > preferable to that? +1 for changing it. Cheers, David. -- David Fetter <david@fetter.org> http://fetter.org/ Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter Skype: davidfetter XMPP: david.fetter@gmail.com Remember to vote! Consider donating to Postgres: http://www.postgresql.org/about/donate
On 12/01/2015 11:20 AM, Tom Lane wrote: > Notice that the dashed lines go all the way to the right margin of my > 80-column terminal window, even though the data requires no more than > 22 columns. While this doesn't look so awful as-is, when I'm working > in a very wide window it starts to look a little silly. > > The behavior I'd have expected is that if the data is narrower than > the window, the lines only go to the right margin of the data. This > is a trivial change to the logic in print_aligned_vertical, but before > I go make it, does anyone want to argue that the current behavior is > preferable to that? If you're fixing the dashed-line code, is there a way to say that we never have more than a reasonable number of dashes (ideally, the width of the terminal) no matter how wide the data is? Having 4000 dashes because of large text on one row is kinda painful, and not at all useful. -- Josh Berkus PostgreSQL Experts Inc. http://pgexperts.com
Sorry, I initially responded only to Josh. Forwarding to list:
On Wed, Dec 2, 2015 at 12:37 PM, Josh Berkus <josh@agliodbs.com> wrote:
> On 12/01/2015 11:20 AM, Tom Lane wrote:
>> Notice that the dashed lines go all the way to the right margin of my
>> 80-column terminal window, even though the data requires no more than
>> 22 columns. While this doesn't look so awful as-is, when I'm working
>> in a very wide window it starts to look a little silly.
>>
>> The behavior I'd have expected is that if the data is narrower than
>> the window, the lines only go to the right margin of the data. This
>> is a trivial change to the logic in print_aligned_vertical, but before
>> I go make it, does anyone want to argue that the current behavior is
>> preferable to that?
>
> If you're fixing the dashed-line code, is there a way to say that we
> never have more than a reasonable number of dashes (ideally, the width
> of the terminal) no matter how wide the data is? Having 4000 dashes
> because of large text on one row is kinda painful, and not at all useful.
If you use \pset format wrapped, then this automatically happens as part of the data wrapping.
If you use the default format (\pset format aligned) in expanded mode, then I agree with you we shouldn't print a half screen full of dashes to separate every tuple. However, a very simple patch to do exactly what you want is what was originally submitted, and was rejected in favor of instead implementing this new feature of \pset format wrapped for expanded mode. Since it was rejected I was reluctant to bring it up again, but like you, I do still think it is a good idea.
You could argue that it is the pager's job to deal with this. If the pager chooses to wrap the parts that don't fit on the screen, it should truncate the separators after one line's width rather than wrapping them. But if it instead shows you a sliding slice of an infinitely-wide screen, then it should keep the separators. But since the pager has no way of knowing that the dashes are separators and not actual data, the pager can't reasonably do a good job of that.
Cheers,
> On 12/01/2015 11:20 AM, Tom Lane wrote:
>> Notice that the dashed lines go all the way to the right margin of my
>> 80-column terminal window, even though the data requires no more than
>> 22 columns. While this doesn't look so awful as-is, when I'm working
>> in a very wide window it starts to look a little silly.
>>
>> The behavior I'd have expected is that if the data is narrower than
>> the window, the lines only go to the right margin of the data. This
>> is a trivial change to the logic in print_aligned_vertical, but before
>> I go make it, does anyone want to argue that the current behavior is
>> preferable to that?
>
> If you're fixing the dashed-line code, is there a way to say that we
> never have more than a reasonable number of dashes (ideally, the width
> of the terminal) no matter how wide the data is? Having 4000 dashes
> because of large text on one row is kinda painful, and not at all useful.
If you use \pset format wrapped, then this automatically happens as part of the data wrapping.
If you use the default format (\pset format aligned) in expanded mode, then I agree with you we shouldn't print a half screen full of dashes to separate every tuple. However, a very simple patch to do exactly what you want is what was originally submitted, and was rejected in favor of instead implementing this new feature of \pset format wrapped for expanded mode. Since it was rejected I was reluctant to bring it up again, but like you, I do still think it is a good idea.
You could argue that it is the pager's job to deal with this. If the pager chooses to wrap the parts that don't fit on the screen, it should truncate the separators after one line's width rather than wrapping them. But if it instead shows you a sliding slice of an infinitely-wide screen, then it should keep the separators. But since the pager has no way of knowing that the dashes are separators and not actual data, the pager can't reasonably do a good job of that.
For those who can't follow my hand-waving, try this:
psql -c 'select * from pg_stats' -x
psql -c 'select * from pg_stats' -x
Cheers,
Jeff
Attachment
Jeff Janes <jeff.janes@gmail.com> writes: > On Wed, Dec 2, 2015 at 12:37 PM, Josh Berkus <josh@agliodbs.com> wrote: >> If you're fixing the dashed-line code, is there a way to say that we >> never have more than a reasonable number of dashes (ideally, the width >> of the terminal) no matter how wide the data is? Having 4000 dashes >> because of large text on one row is kinda painful, and not at all useful. > If you use the default format (\pset format aligned) in expanded mode, then > I agree with you we shouldn't print a half screen full of dashes to > separate every tuple. Don't think I agree. Suppose that you have a wider-than-screen table and you use a pager to scroll left and right in that. If we shorten the dashed lines, then once you scroll to the right of wherever they stop, you lose that visual cue separating the rows. This matters a lot if only a few of the column values are very wide: everywhere else, there's gonna be lots of whitespace. In the situation you are describing, you've already pretty much lost user-friendliness of the display, and the only way to get it back is to use a suitable pager (or make the window bigger, but that only goes so far). So I don't think we should optimize the non-pager case at the expense of the pager case. It's possible that it'd be worth the trouble to give psql two operating modes, one for pagers with left-right scroll ability and one for those without. But that would be a good deal more work than what I propose to do at the moment. regards, tom lane
On 12/02/2015 05:24 PM, Tom Lane wrote: > Don't think I agree. Suppose that you have a wider-than-screen table > and you use a pager to scroll left and right in that. If we shorten the > dashed lines, then once you scroll to the right of wherever they stop, > you lose that visual cue separating the rows. This matters a lot if > only a few of the column values are very wide: everywhere else, there's > gonna be lots of whitespace. What pager lets me scroll right infinitely? Because I wanna install that. -- Josh Berkus PostgreSQL Experts Inc. http://pgexperts.com
On Wed, Dec 02, 2015 at 10:36:56PM -0500, Josh Berkus wrote: > On 12/02/2015 05:24 PM, Tom Lane wrote: > > Don't think I agree. Suppose that you have a wider-than-screen table > > and you use a pager to scroll left and right in that. If we shorten the > > dashed lines, then once you scroll to the right of wherever they stop, > > you lose that visual cue separating the rows. This matters a lot if > > only a few of the column values are very wide: everywhere else, there's > > gonna be lots of whitespace. > > What pager lets me scroll right infinitely? Because I wanna install that. I don't know about infinitely, but at least with the -S (no wrap) option, less lets you use left- and right-arrow, prefixed by multipliers, if you like, to scroll horizontally And now I have learned something new about a pager I've used every day for decades. Cheers, David. -- David Fetter <david@fetter.org> http://fetter.org/ Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter Skype: davidfetter XMPP: david.fetter@gmail.com Remember to vote! Consider donating to Postgres: http://www.postgresql.org/about/donate
On Wed, Dec 2, 2015 at 7:59 PM, David Fetter <david@fetter.org> wrote: > On Wed, Dec 02, 2015 at 10:36:56PM -0500, Josh Berkus wrote: >> On 12/02/2015 05:24 PM, Tom Lane wrote: >> > Don't think I agree. Suppose that you have a wider-than-screen table >> > and you use a pager to scroll left and right in that. If we shorten the >> > dashed lines, then once you scroll to the right of wherever they stop, >> > you lose that visual cue separating the rows. This matters a lot if >> > only a few of the column values are very wide: everywhere else, there's >> > gonna be lots of whitespace. >> >> What pager lets me scroll right infinitely? Because I wanna install that. > > I don't know about infinitely, but at least with the -S (no wrap) > option, less lets you use left- and right-arrow, prefixed by > multipliers, if you like, to scroll horizontally > > And now I have learned something new about a pager I've used every day > for decades. And even if you don't specify -S, 'less' will jump into that mode anyway as soon as you hit the right array. It starts out wrapping, but hit the right arrow and it undoes the wrap. So I often do hit '1' right arrow to get out of the wrap situation described above. I do lose the leftmost character on the screen. Then you can left-arrow all the way back to the left, and it jumps back into wrap mode. Pretty darn useful at times. Now, if I could just find a way to tell 'less' after-the-fact "pretend I started you up with the -X flag". Once I find the part I want, I want to quit the pager without clearing that stuff off of the screen. Sometimes. Cheers, Jeff
On Wed, Dec 2, 2015 at 5:24 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote: > Jeff Janes <jeff.janes@gmail.com> writes: >> On Wed, Dec 2, 2015 at 12:37 PM, Josh Berkus <josh@agliodbs.com> wrote: >>> If you're fixing the dashed-line code, is there a way to say that we >>> never have more than a reasonable number of dashes (ideally, the width >>> of the terminal) no matter how wide the data is? Having 4000 dashes >>> because of large text on one row is kinda painful, and not at all useful. > >> If you use the default format (\pset format aligned) in expanded mode, then >> I agree with you we shouldn't print a half screen full of dashes to >> separate every tuple. > > Don't think I agree. Suppose that you have a wider-than-screen table > and you use a pager to scroll left and right in that. If we shorten the > dashed lines, then once you scroll to the right of wherever they stop, > you lose that visual cue separating the rows. This matters a lot if > only a few of the column values are very wide: everywhere else, there's > gonna be lots of whitespace. For what it's worth, I'm with Josh and Jeff. My pager, like nearly everybody else's, is less. And it's not stupid to have a behavior that works reasonably with less's default settings. I haven't kept a count of the number of times I've had to scroll down through endless pages of dashes in order to find some data that's not dashes, but it's surely quite a few. Your point is also valid, so I don't mean to detract from that. But the status quo is definitely annoying. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
On 12/8/15 1:36 PM, Robert Haas wrote: > Your point is also valid, so I don't mean to detract from that. But > the status quo is definitely annoying. +1, and I even use -S. -- Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX Experts in Analytics, Data Architecture and PostgreSQL Data in Trouble? Get it in Treble! http://BlueTreble.com
On Wed, Dec 2, 2015 at 5:24 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Jeff Janes <jeff.janes@gmail.com> writes:
>> On Wed, Dec 2, 2015 at 12:37 PM, Josh Berkus <josh@agliodbs.com> wrote:
>>> If you're fixing the dashed-line code, is there a way to say that we
>>> never have more than a reasonable number of dashes (ideally, the width
>>> of the terminal) no matter how wide the data is? Having 4000 dashes
>>> because of large text on one row is kinda painful, and not at all useful.
>
>> If you use the default format (\pset format aligned) in expanded mode, then
>> I agree with you we shouldn't print a half screen full of dashes to
>> separate every tuple.
>
> Don't think I agree. Suppose that you have a wider-than-screen table
> and you use a pager to scroll left and right in that. If we shorten the
> dashed lines, then once you scroll to the right of wherever they stop,
> you lose that visual cue separating the rows. This matters a lot if
> only a few of the column values are very wide: everywhere else, there's
> gonna be lots of whitespace.
For what it's worth, I'm with Josh and Jeff. My pager, like nearly
everybody else's, is less. And it's not stupid to have a behavior
that works reasonably with less's default settings. I haven't kept a
count of the number of times I've had to scroll down through endless
pages of dashes in order to find some data that's not dashes, but it's
surely quite a few.
Your point is also valid, so I don't mean to detract from that. But
the status quo is definitely annoying.
for those wishing to change the status quo the question is whether there needs to be a way to get back to the present behavior and, more generally, configure the behavior to taste while still having a reasonable default.
Losing a bit of usability in not being able to identify record boundaries while viewing off to the right seems is a trade-off that feels right to me. During interactive use SELECT * is quite useful but is hampered on relations that just happen to have a wide column that you don't care about but also don't want to waste the effort to specify all column names except that one.
So +1 from me.
David J.