Обсуждение: [COMMITTERS] pgsql: Add psql variables showing server version and psql version.

Add psql variables showing server version and psql version.

We already had a psql variable VERSION that shows the verbose form of
psql's own version.  Add VERSION_NAME to show the short form (e.g.,
"11devel") and VERSION_NUM to show the numeric form (e.g., 110000).
Also add SERVER_VERSION_NAME and SERVER_VERSION_NUM to show the short and
numeric forms of the server's version.  (We'd probably add SERVER_VERSION
with the verbose string if it were readily available; but adding another
network round trip to get it seems too expensive.)

The numeric forms, in particular, are expected to be useful for scripting
purposes, now that psql can do conditional tests.

Fabien Coelho, reviewed by Pavel Stehule

Discussion: https://postgr.es/m/alpine.DEB.2.20.1704020917220.4632@lancre

Branch
------
master

Details
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https://git.postgresql.org/pg/commitdiff/9ae9d8c1549c384dbdb8363e1d932b7311d25c56

Modified Files
--------------
doc/src/sgml/ref/psql-ref.sgml | 24 ++++++++++++++++++++++--
src/bin/psql/command.c         | 19 +++++++++++++++++++
src/bin/psql/help.c            |  9 ++++++++-
src/bin/psql/startup.c         |  3 +++
4 files changed, 52 insertions(+), 3 deletions(-)

On 5 September 2017 at 07:51, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Add psql variables showing server version and psql version.
>
> We already had a psql variable VERSION that shows the verbose form of
> psql's own version.  Add VERSION_NAME to show the short form (e.g.,
> "11devel") and VERSION_NUM to show the numeric form (e.g., 110000).
> Also add SERVER_VERSION_NAME and SERVER_VERSION_NUM to show the short and
> numeric forms of the server's version.  (We'd probably add SERVER_VERSION
> with the verbose string if it were readily available; but adding another
> network round trip to get it seems too expensive.)
>
> The numeric forms, in particular, are expected to be useful for scripting
> purposes, now that psql can do conditional tests.

This is good.

Please can we backpatch these are far as they will go (easily)?

There is very little risk in doing so and significant benefits in
being able to rely on scripts that know about versions.

Thanks

--
Simon Riggs                http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services