Re: [HACKERS] Multiple psql history files

2016-10-18 Thread David G. Johnston 
On Tue, Oct 18, 2016 at 10:21 AM, Tom Lane  wrote:

> "David G. Johnston"  writes:
> > On Tue, Oct 18, 2016 at 9:45 AM, Tom Lane  wrote:
> >> One interesting point, if you wish to consider history as being
> >> connection-specific, is what happens during a \c command.  Right
> >> now the answer is "nothing" but you might wish it were different.
>
> > ​Just to clarify/confirm a point inferred from the docs...
> > If you place "\set HISTFILE​ ~/.psql_history- :DBNAME"
> > ​into your .psqlrc file then when you perform a "\c" the .psqlrc file is
> > re-read and the ​new value for DBNAME is used to generate a new history
> > file name.
>
> Um, no, I see no indication of that in the code.  Where did you read that
> in the docs?
>
>
​
​
 DBNAME
The name of the database you are currently connected to. This is set every
time you connect to a database (including program start-up), but can be
unset.

​​HISTFILE
The file name that will be used to store the history list. The default
value is ~/.psql_history. For example, putting:
\set HISTFILE ~/.psql_history- :DBNAME
in ~/.psqlrc will cause psql to maintain a separate history for each
database.

​The "including program start-up" aspect to DBNAME means that it is changed
upon using "\c"

I inferred the part about .psqlrc being re-read and thus taking on the new
value of :DBNAME in the example.

psqlrc is later defined to be "the [system|user] startup file" so it was
wrong to conclude that it was re-read upon issuing "\c" - though
"connection startup" isn't a totally unreasonable interpretation of the
timing at which this file is read.  Not everyone is going to associate the
"rc" suffix with the file only being read during program startup.
​


> If we wanted the history file to change at \c, I think the best way would
> be to invent some escape-patterns that could be placed in the value of
> HISTFILE, say along the lines of "\set HISTFILE ~/.psql_history-%h-%p",
> and then specify that if the value contains any such patterns we'll dump
> and reload the history file when reconnecting.  But TBH I don't think
> it's worth the trouble.  I'd sure like to have seen multiple requests
> for such functionality before we go to the trouble.
>

A slightly less invasive approach would be to have a "connection startup
script" file..."psql-conn-rc"...that is re-read immediately after a
successful connection is made to a database.

David J.

Re: [HACKERS] Multiple psql history files

2016-10-18 Thread Tom Lane 
"David G. Johnston"  writes:
> On Tue, Oct 18, 2016 at 9:45 AM, Tom Lane  wrote:
>> One interesting point, if you wish to consider history as being
>> connection-specific, is what happens during a \c command.  Right
>> now the answer is "nothing" but you might wish it were different.

> ​Just to clarify/confirm a point inferred from the docs...
> If you place "\set HISTFILE​ ~/.psql_history- :DBNAME"
> ​into your .psqlrc file then when you perform a "\c" the .psqlrc file is
> re-read and the ​new value for DBNAME is used to generate a new history
> file name.

Um, no, I see no indication of that in the code.  Where did you read that
in the docs?

If we wanted the history file to change at \c, I think the best way would
be to invent some escape-patterns that could be placed in the value of
HISTFILE, say along the lines of "\set HISTFILE ~/.psql_history-%h-%p",
and then specify that if the value contains any such patterns we'll dump
and reload the history file when reconnecting.  But TBH I don't think
it's worth the trouble.  I'd sure like to have seen multiple requests
for such functionality before we go to the trouble.

regards, tom lane


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Re: [HACKERS] Multiple psql history files

2016-10-18 Thread David G. Johnston 
On Tue, Oct 18, 2016 at 9:45 AM, Tom Lane  wrote:

> Jonathan Jacobson  writes:
> > The .psql_history file is naturally used by different DB connections
> > (distinguished by a different combination of host + port + database +
> user).
> > At least in my multi-database working environment, this leads sometimes
> to
> > frustration because there are commands that cannot or should not be used
> by
> > different connections.
> > To solve this, psql could keep a separate command history file for each
> > connection.
> > I will be happy to make this my first contribution to PostgreSQL's code.
> > What do you say?
>
> One interesting point, if you wish to consider history as being
> connection-specific, is what happens during a \c command.  Right
> now the answer is "nothing" but you might wish it were different.
>

​Just to clarify/confirm a point inferred from the docs...

If you place "\set HISTFILE​ ~/.psql_history- :DBNAME
"
​
​
​into your .psqlrc file then when you perform a "\c" the .psqlrc file is
re-read and the ​new value for DBNAME is used to generate a new history
file name.

​As Julien pointed out cross-thread this really does seem to be the best
place to implement such logic - though shell functions and aliases can be
used to some good effect as well.

David J.

Re: [HACKERS] Multiple psql history files

2016-10-18 Thread Tom Lane 
Jonathan Jacobson  writes:
> The .psql_history file is naturally used by different DB connections
> (distinguished by a different combination of host + port + database + user).
> At least in my multi-database working environment, this leads sometimes to
> frustration because there are commands that cannot or should not be used by
> different connections.
> To solve this, psql could keep a separate command history file for each
> connection.
> I will be happy to make this my first contribution to PostgreSQL's code.
> What do you say?

Personally, I'd be strongly against that because I frequently *want*
to re-use the same command on different connections.  As an example,
comparing the behavior of the same command in different PG versions
(hence different postmasters) is an everyday task for me.

I can see that others might have different needs, but surely this
is going to be a use-case-specific requirement.

It's already possible to control which history file is used via psql's
HISTFILE variable and/or the PSQL_HISTORY environment variable.  Perhaps
you can solve your problem today by manipulating those?

One interesting point, if you wish to consider history as being
connection-specific, is what happens during a \c command.  Right
now the answer is "nothing" but you might wish it were different.

regards, tom lane


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Re: [HACKERS] Multiple psql history files

2016-10-18 Thread David G. Johnston 
On Tue, Oct 18, 2016 at 9:26 AM, Jonathan Jacobson  wrote:

> The .psql_history file is naturally used by different DB connections
> (distinguished by a different combination of host + port + database + user).
> At least in my multi-database working environment, this leads sometimes to
> frustration because there are commands that cannot or should not be used by
> different connections.
> To solve this, psql could keep a separate command history file for each
> connection.
> I will be happy to make this my first contribution to PostgreSQL's code.
> What do you say?
>
>
​Existing capabilities not withstanding the feature itself would probably
be considered but I'm doubtful it would replace the default behavior.

The user would, at minimum, have to designate​

​a directory into which the separate history files would be created -
polluting the home directory is unappealing.

If you want to propose the specifics of a feature that meets those two
criteria specific comments and opinions on include-ability can be made.

David J.
​

Re: [HACKERS] Multiple psql history files

2016-10-18 Thread Julien Rouhaud 
On 18/10/2016 18:26, Jonathan Jacobson wrote:
> The .psql_history file is naturally used by different DB connections
> (distinguished by a different combination of host + port + database + user).
> At least in my multi-database working environment, this leads sometimes
> to frustration because there are commands that cannot or should not be
> used by different connections.
> To solve this, psql could keep a separate command history file for each
> connection.

You can already do this, for instance in your .psqlrc:

\set HISTFILE ~/.psql_history- :HOST - :PORT - :DBNAME - :USER


-- 
Julien Rouhaud
http://dalibo.com - http://dalibo.org


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Re: [HACKERS] Multiple psql history files

2016-10-18 Thread David G. Johnston 
On Tue, Oct 18, 2016 at 9:26 AM, Jonathan Jacobson  wrote:

> The .psql_history file is naturally used by different DB connections
> (distinguished by a different combination of host + port + database + user).
> At least in my multi-database working environment, this leads sometimes to
> frustration because there are commands that cannot or should not be used by
> different connections.
> To solve this, psql could keep a separate command history file for each
> connection.
> I will be happy to make this my first contribution to PostgreSQL's code.
> What do you say?
>

​I would say that users needing such fine grained control of the history
file should avail themselves of HISTFILE ​and other related psql variables
and/or the PSQL_HISTORY environment variable.

David J.

Re: [HACKERS] Multiple psql history files

2016-10-18 Thread Corey Huinker 
On Tue, Oct 18, 2016 at 12:26 PM, Jonathan Jacobson 
wrote:

> The .psql_history file is naturally used by different DB connections
> (distinguished by a different combination of host + port + database + user).
> At least in my multi-database working environment, this leads sometimes to
> frustration because there are commands that cannot or should not be used by
> different connections.
> To solve this, psql could keep a separate command history file for each
> connection.
> I will be happy to make this my first contribution to PostgreSQL's code.
> What do you say?
>
> Regards,
> Jonathan
>

That's settable with HISTFILE

\set HISTFILE ~/.psql_history- :DBNAME

There's also :PORT and a few other vars.

(example borrowed from
http://stackoverflow.com/questions/17924906/where-is-psql-client-history-kept-psql-history-non-existant
)

[HACKERS] Multiple psql history files

2016-10-18 Thread Jonathan Jacobson 
The .psql_history file is naturally used by different DB connections
(distinguished by a different combination of host + port + database + user).
At least in my multi-database working environment, this leads sometimes to
frustration because there are commands that cannot or should not be used by
different connections.
To solve this, psql could keep a separate command history file for each
connection.
I will be happy to make this my first contribution to PostgreSQL's code.
What do you say?

Regards,
Jonathan