út 4. 4. 2023 v 18:42 odesílatel Tom Lane <[email protected]> napsal:
> Kirk Wolak <[email protected]> writes:
> > Changed status to Ready for Committer. (100% Guessing here...)
>
> Basically, I want to reject this on the grounds that it's not
> useful enough to justify the overhead of marking the "role" GUC
> as GUC_REPORT. The problems with it not going to work properly
> with old servers are an additional reason not to like it.
>
If I understand to next comment correctly, the overhead should not be too
big
/*
* ReportChangedGUCOptions: report recently-changed GUC_REPORT variables
*
* This is called just before we wait for a new client query.
*
* By handling things this way, we ensure that a ParameterStatus message
* is sent at most once per variable per query, even if the variable
* changed multiple times within the query. That's quite possible when
* using features such as function SET clauses. Function SET clauses
* also tend to cause values to change intraquery but eventually revert
* to their prevailing values; ReportGUCOption is responsible for avoiding
* redundant reports in such cases.
*/
>
> But, if I lose the argument and we do commit this, I think it
> should just print an empty string when dealing with an old server.
> "ERR02000" is an awful idea, not least because it could be a
> real role name.
>
ok
>
> BTW, we should probably get rid of the PQuser() fallback in
> %n (session_username()) as well. It's unlikely that there are
> still servers in the wild that don't report "session_authorization",
> but if we did find one then the output is potentially misleading.
> I'd rather print nothing than something that might not be your
> actual session authorization setting.
>
It should be a separate patch?
Updated patch attached
Regards
Pavel
>
> regards, tom lane
>
diff --git a/doc/src/sgml/libpq.sgml b/doc/src/sgml/libpq.sgml
index 9f72dd29d8..966cce9559 100644
--- a/doc/src/sgml/libpq.sgml
+++ b/doc/src/sgml/libpq.sgml
@@ -2482,6 +2482,7 @@ const char *PQparameterStatus(const PGconn *conn, const char *paramName);
<varname>in_hot_standby</varname>,
<varname>is_superuser</varname>,
<varname>session_authorization</varname>,
+ <varname>role</varname>,
<varname>DateStyle</varname>,
<varname>IntervalStyle</varname>,
<varname>TimeZone</varname>,
@@ -2496,7 +2497,8 @@ const char *PQparameterStatus(const PGconn *conn, const char *paramName);
9.0;
<varname>default_transaction_read_only</varname> and
<varname>in_hot_standby</varname> were not reported by releases before
- 14.)
+ 14;
+ <varname>role</varname> was not reported by releases before 16;)
Note that
<varname>server_version</varname>,
<varname>server_encoding</varname> and
diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 29bbec2188..330c085329 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -4540,7 +4540,26 @@ testdb=> <userinput>INSERT INTO my_table VALUES (:'content');</userinput>
<listitem><para>The port number at which the database server is listening.</para></listitem>
</varlistentry>
- <varlistentry id="app-psql-prompting-n">
+ <varlistentry id="app-psql-prompting-n-uc">
+ <term><literal>%N</literal></term>
+ <listitem>
+ <para>
+ The database role name. This value is specified by command
+ <command>SET ROLE</command>. Until execution of this command
+ the value is <literal>none</literal>. The value is same like
+ the value of the parameter <varname>role</varname> (can be
+ displayed by <command>SHOW</command>.
+ </para>
+
+ <para>
+ This substitution requires <productname>PostgreSQL</productname>
+ version 15 and up. When you use older version, the empty string
+ is used instead.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry id="app-psql-prompting-n-lc">
<term><literal>%n</literal></term>
<listitem>
<para>
diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c
index 8062589efd..3eec4768b3 100644
--- a/src/backend/utils/misc/guc_tables.c
+++ b/src/backend/utils/misc/guc_tables.c
@@ -4174,7 +4174,7 @@ struct config_string ConfigureNamesString[] =
{"role", PGC_USERSET, UNGROUPED,
gettext_noop("Sets the current role."),
NULL,
- GUC_IS_NAME | GUC_NO_SHOW_ALL | GUC_NO_RESET_ALL | GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_NOT_WHILE_SEC_REST
+ GUC_IS_NAME | GUC_REPORT | GUC_NO_SHOW_ALL | GUC_NO_RESET_ALL | GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_NOT_WHILE_SEC_REST
},
&role_string,
"none",
diff --git a/src/bin/psql/prompt.c b/src/bin/psql/prompt.c
index 969cd9908e..a304fe1868 100644
--- a/src/bin/psql/prompt.c
+++ b/src/bin/psql/prompt.c
@@ -165,6 +165,35 @@ get_prompt(promptStatus_t status, ConditionalStack cstack)
if (pset.db)
strlcpy(buf, session_username(), sizeof(buf));
break;
+ /* DB server user role */
+ case 'N':
+ if (pset.db)
+ {
+ int minServerMajor;
+ int serverMajor;
+ const char *val;
+
+ /*
+ * This feature requires GUC "role" to be marked
+ * as GUC_REPORT. Without it is hard to specify fallback
+ * result. Returning empty value can be messy, returning
+ * PQuser like session_username can be messy too.
+ * Exec query is not too practical too, because it doesn't
+ * work when session is not in transactional state, and
+ * CURRENT_ROLE returns different result when role is not
+ * explicitly specified by SET ROLE.
+ */
+ minServerMajor = 1600;
+ serverMajor = PQserverVersion(pset.db) / 100;
+ if (serverMajor >= minServerMajor)
+ val = PQparameterStatus(pset.db, "role");
+
+ if (val)
+ strlcpy(buf, val, sizeof(buf));
+ else
+ buf[0] = '\0';
+ }
+ break;
/* backend pid */
case 'p':
if (pset.db)
