Re: Variable substitution in psql backtick expansion

2017-04-02 13:13 GMT+02:00 Fabien COELHO <coelho(at)cri(dot)ensmp(dot)fr>:

>
> Hello Pavel,
>
> \echo :VERSION
>>> PostgreSQL 10devel on x86_64-pc-linux-gnu, compiled by gcc (Ubuntu
>>> 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609, 64-bit
>>>
>>> Probably some :VERSION_NUM would make some sense. See attached PoC patch.
>>> Would it make sense?
>>>
>>
>> Maybe better name for you CLIENT_VERSION_NUM
>>
>
> If it was starting from nothing I would tend to agree with you, but there
> is already an existing :VERSION variable, so it seemed logical to keep on
> and create variants with the same prefix.

you have true - so VERSION_NUM should be client side version

>
>
> Can be SERVER_VERSION_NUM taken from connection info?
>>
>
> Probably it could. It seems a little less straightforward than defining a
> client-side string at compile time. The information is displayed when the
> connection is established, so the information is there somewhere.
>

It is not too hard

diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index 94a3cfce90..d1ae81646f 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -3320,16 +3320,21 @@ checkWin32Codepage(void)
void
SyncVariables(void)
{
+ char buffer[100];
+
/* get stuff from connection */
pset.encoding = PQclientEncoding(pset.db);
pset.popt.topt.encoding = pset.encoding;
pset.sversion = PQserverVersion(pset.db);

+ snprintf(buffer, 100, "%d", pset.sversion);
+
SetVariable(pset.vars, "DBNAME", PQdb(pset.db));
SetVariable(pset.vars, "USER", PQuser(pset.db));
SetVariable(pset.vars, "HOST", PQhost(pset.db));
SetVariable(pset.vars, "PORT", PQport(pset.db));
SetVariable(pset.vars, "ENCODING", pg_encoding_to_char(pset.encoding));
+ SetVariable(pset.vars, "SVERSION_NUM", buffer);

/* send stuff to it, too */
PQsetErrorVerbosity(pset.db, pset.verbosity);

Regards

Pavel

>
> psql (10devel, server 9.6.2)
>
> --
> Fabien.
>