Disallow a digit as the first character of a variable name in pgbench.

The point of this restriction is to avoid trying to substitute variables
into timestamp literal values, which may contain strings like '12:34'.

There is a good deal more that should be done to reduce pgbench's
tendency to substitute where it shouldn't.  But this is sufficient to
solve the case complained of by Jaime Soler, and it's simple enough
to back-patch.

Back-patch to v11; before commit 9d36a3866, pgbench had a slightly
different definition of what a variable name is, and anyway it seems
unwise to change long-stable branches for this.

Fabien Coelho

Discussion: https://postgr.es/m/alpine.DEB.2.22.394.2006291740420.805678@pseudo

1 files changed, 1 insertions, 1 deletions

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index b03d0cc50f5..faa7c26b0a1 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -1008,7 +1008,7 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d
   <para>
    There is a simple variable-substitution facility for script files.
    Variable names must consist of letters (including non-Latin letters),
-   digits, and underscores.
+   digits, and underscores, with the first character not being a digit.
    Variables can be set by the command-line <option>-D</option> option,
    explained above, or by the meta commands explained below.
    In addition to any variables preset by <option>-D</option> command-line options,