Re: Variable substitution in psql backtick expansion - Mailing list pgsql-hackers

2017-04-02 13:13 GMT+02:00 Fabien COELHO <coelho@cri.ensmp.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.