psql: customizable readline history filename

This has been saved for the 8.1 release:

http:/momjian.postgresql.org/cgi-bin/pgpatches2

---------------------------------------------------------------------------

Andreas Seltenreich wrote:

Hi,

the following patch makes the filename used to store the readline
history customizable through a variable named HISTFILE, analogous to
psql's already implemented HISTCONTROL and HISTSIZE variables, and
bash's HISTFILE-Variable.

The motivation was to be able to get psql to maintain separate
histories for separate databases. This is now easily achievable
through a line like the following in ~/.psqlrc:

\set HISTFILE ~/.psql_history- :DBNAME

regards,
Andreas

Index: doc/src/sgml/ref/psql-ref.sgml
===================================================================
RCS file: /projects/cvsroot/pgsql/doc/src/sgml/ref/psql-ref.sgml,v
retrieving revision 1.123
diff -c -r1.123 psql-ref.sgml
*** doc/src/sgml/ref/psql-ref.sgml	6 Oct 2004 18:39:15 -0000	1.123
--- doc/src/sgml/ref/psql-ref.sgml	26 Oct 2004 05:57:57 -0000
***************
*** 1973,1978 ****
--- 1973,2001 ----
</varlistentry>

<varlistentry>
+         <term><varname>HISTFILE</varname></term>
+         <listitem>
+         <para>
+ 	This variable contains the filename used to save the history.
+         Its default value is <filename>~/.psql_history</filename>.
+         When unset or empty, the command history is not saved upon
+         program termination.  For example, 
+ <programlisting>
+ \set HISTFILE ~/.psql_history- :DBNAME
+ </programlisting>
+         in your <filename>~/.psqlrc</filename> will get psql to
+         maintain a separate history for each database.
+         </para>
+         <note>
+         <para>
+         This feature was shamelessly plagiarized from
+         <application>Bash</application>.
+         </para>
+         </note>
+         </listitem>
+       </varlistentry>
+ 
+       <varlistentry>
<term><varname>HISTSIZE</varname></term>
<listitem>
<para>
Index: src/bin/psql/input.c
===================================================================
RCS file: /projects/cvsroot/pgsql/src/bin/psql/input.c,v
retrieving revision 1.41
diff -c -r1.41 input.c
*** src/bin/psql/input.c	12 Oct 2004 21:54:44 -0000	1.41
--- src/bin/psql/input.c	26 Oct 2004 05:57:57 -0000
***************
*** 38,46 ****
static void finishInput(int, void *);
#endif

- #define PSQLHISTORY ".psql_history"
- 
- 
#ifdef USE_READLINE
static enum histcontrol
GetHistControlConfig(void)
--- 38,43 ----
***************
*** 167,173 ****
#ifdef USE_READLINE
if (flags & 1)
{
! 		char		home[MAXPGPATH];

useReadline = true;
initialize_readline();
--- 164,171 ----
#ifdef USE_READLINE
if (flags & 1)
{
! 		const char *psql_history;
! 		char	   *tilde_expanded;

useReadline = true;
initialize_readline();
***************
*** 176,191 ****
if (GetVariable(pset.vars, "HISTSIZE") == NULL)
SetVariable(pset.vars, "HISTSIZE", "500");
using_history();
- if (get_home_path(home))
- {
- char *psql_history;

! psql_history = pg_malloc(strlen(home) + 1 +
! strlen(PSQLHISTORY) + 1);
! sprintf(psql_history, "%s/%s", home, PSQLHISTORY);
! read_history(psql_history);
! free(psql_history);
! }
}
#endif

--- 174,189 ----
if (GetVariable(pset.vars, "HISTSIZE") == NULL)
SetVariable(pset.vars, "HISTSIZE", "500");
using_history();

! if (GetVariable(pset.vars, "HISTFILE") == NULL)
! SetVariable(pset.vars, "HISTFILE", "~/.psql_history");
!
! psql_history = GetVariable(pset.vars, "HISTFILE");
!
! tilde_expanded = pg_strdup(psql_history);
! expand_tilde(&tilde_expanded);
! read_history(tilde_expanded);
! free(tilde_expanded);
}
#endif

***************
*** 228,252 ****
#ifdef USE_READLINE
if (useHistory)
{
! char home[MAXPGPATH];
!
! if (get_home_path(home))
! {
! char *psql_history;
! int hist_size;

! psql_history = pg_malloc(strlen(home) + 1 +
! strlen(PSQLHISTORY) + 1);

! hist_size = GetVariableNum(pset.vars, "HISTSIZE", -1, -1, true);

! 			if (hist_size >= 0)
! 				stifle_history(hist_size);
! 
! 			sprintf(psql_history, "%s/%s", home, PSQLHISTORY);
! 			write_history(psql_history);
! 			free(psql_history);
! 		}
}
#endif
}
--- 226,251 ----
#ifdef USE_READLINE
if (useHistory)
{
! 		const char *psql_history;
! 		char	   *tilde_expanded;
! 		int			hist_size;
! 		
! 		psql_history = GetVariable(pset.vars, "HISTFILE");
! 
! 		if (!psql_history || !strlen(psql_history))
! 			return;
! 			
! 		tilde_expanded = pg_strdup(psql_history);
! 		expand_tilde(&tilde_expanded);
! 		
! 		hist_size = GetVariableNum(pset.vars, "HISTSIZE", -1, -1, true);

! if (hist_size >= 0)
! stifle_history(hist_size);

! saveHistory(tilde_expanded);

! free(tilde_expanded);
}
#endif
}

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-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073

Andreas Seltenreich wrote:

Hi,

the following patch makes the filename used to store the readline
history customizable through a variable named HISTFILE, analogous to
psql's already implemented HISTCONTROL and HISTSIZE variables, and
bash's HISTFILE-Variable.

The motivation was to be able to get psql to maintain separate
histories for separate databases. This is now easily achievable
through a line like the following in ~/.psqlrc:

\set HISTFILE ~/.psql_history- :DBNAME

I have applied your patch with slight modifications; new version
attached.

Win32 doesn't have tilde expansion, so your idea of using
"~/.psql_history" as a default would not work --- I had to keep the
get_home_path() code in there.

I decided to make psql_history a file static variable, so we would not
have to recompute its value when writing the history file.

I noticed your documentation example had a space before :DBNAME --- I
removed the space.

You had the idea of not saving the history on exit if HISTFILE is not
set. I don't think we have community agreement on that change, and I
bet we wouldn't get it. (I have removed your documentation mention of
this.) I think setting HISTSIZE to zero has that effect already if
people want it.

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073

Bruce Momjian schrob:

I noticed your documentation example had a space before :DBNAME --- I
removed the space.

This space is necessary for proper expansion of the parameter. The
\set-Command concatenates all its arguments after expansion:

--8<---------------cut here---------------start------------->8---
scratch=# \set HISTFILE .psql_history-:DBNAME
scratch=# \echo :HISTFILE
.psql_history-:DBNAME
scratch=# \set HISTFILE .psql_history- :DBNAME
scratch=# \echo :HISTFILE
.psql_history-scratch
scratch=#
--8<---------------cut here---------------end--------------->8---

You had the idea of not saving the history on exit if HISTFILE is not
set. I don't think we have community agreement on that change, and I
bet we wouldn't get it. (I have removed your documentation mention of
this.) I think setting HISTSIZE to zero has that effect already if
people want it.

I went for bash's behaviour back then, since we copied bash's
semantics with the other history options too.

Thanks!
Andreas

Andreas Seltenreich wrote:

Bruce Momjian schrob:

I noticed your documentation example had a space before :DBNAME --- I
removed the space.

This space is necessary for proper expansion of the parameter. The
\set-Command concatenates all its arguments after expansion:

--8<---------------cut here---------------start------------->8---
scratch=# \set HISTFILE .psql_history-:DBNAME
scratch=# \echo :HISTFILE
.psql_history-:DBNAME
scratch=# \set HISTFILE .psql_history- :DBNAME
scratch=# \echo :HISTFILE
.psql_history-scratch
scratch=#
--8<---------------cut here---------------end--------------->8---

You had the idea of not saving the history on exit if HISTFILE is not
set. I don't think we have community agreement on that change, and I
bet we wouldn't get it. (I have removed your documentation mention of
this.) I think setting HISTSIZE to zero has that effect already if
people want it.

I went for bash's behaviour back then, since we copied bash's
semantics with the other history options too.

Ah, I see. I tested ':' expansion in queries and found the space wasn't
needed, but I see now that with \set it is needed:

test=> \set x a
test=> \echo :x
a
test=> \set y b:x
test=> \echo :y
b:x
test=> \set y b :x
test=> \echo :y
ba

I will update the documentation to add the space. Thanks.

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073