Обсуждение: Should we get rid of custom_variable_classes altogether?
During the discussion of Alexey Klyukin's rewrite of ParseConfigFile,
considerable unhappiness was expressed by various people about the
complexity and relative uselessness of the custom_variable_classes GUC.
While working over his patch just now, I've come around to the side that
was saying that this variable isn't worth its keep. We don't have any
way to validate whether the second part of a qualified GUC name is
correct, if its associated extension module isn't loaded, so how much
point is there in validating the first part? And the variable is
certainly a pain in the rear both to DBAs and to the GUC code itself.
So at this point I'd vote for just dropping it and always allowing
custom (that is, qualified) GUC names to be set, whether the prefix
corresponds to any loaded module or not.
Comments, other proposals?
regards, tom lane
On Sun, Oct 2, 2011 at 10:05 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote: > During the discussion of Alexey Klyukin's rewrite of ParseConfigFile, > considerable unhappiness was expressed by various people about the > complexity and relative uselessness of the custom_variable_classes GUC. > While working over his patch just now, I've come around to the side that > was saying that this variable isn't worth its keep. We don't have any > way to validate whether the second part of a qualified GUC name is > correct, if its associated extension module isn't loaded, so how much > point is there in validating the first part? And the variable is > certainly a pain in the rear both to DBAs and to the GUC code itself. > > So at this point I'd vote for just dropping it and always allowing > custom (that is, qualified) GUC names to be set, whether the prefix > corresponds to any loaded module or not. Sounds sensible. One less thing to configure is a good thing. -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
Simon Riggs <simon@2ndQuadrant.com> writes:
> On Sun, Oct 2, 2011 at 10:05 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> So at this point I'd vote for just dropping it and always allowing
>> custom (that is, qualified) GUC names to be set, whether the prefix
>> corresponds to any loaded module or not.
> Sounds sensible. One less thing to configure is a good thing.
Attached is a draft patch for that.
While working on this I got annoyed at our cheesy handling of the
situation where a "placeholder" value has to be turned into a real
setting, which happens when the corresponding extension gets loaded.
There are several issues:
1. If it's a SUSET variable, a preceding attempt to set the value via
SET will fail even if you're a superuser, for example
regression=# set plpgsql.variable_conflict = use_variable;
SET
regression=# load 'plpgsql';
ERROR: permission denied to set parameter "plpgsql.variable_conflict"
The reason for that is that define_custom_variable doesn't know whether
the pre-existing value was set by a superuser, so it must assume the
worst. Seems like we could easily fix that by having set_config_option
set a flag in the GUC variable noting whether a SET was done by a
superuser or not.
2. If you do get an error while re-assigning the pre-existing value of
the variable, it's thrown as an ERROR. This is really pretty nasty
because it'll abort execution of the extension module's init function;
for example, a likely consequence is that other custom variables of
the module don't set set up correctly, and it could easily be a lot
worse if there are other things the init function hasn't done yet.
I think we need to arrange that set_config_option only reports failures
to apply such values as WARNING, not ERROR. There isn't anything in its
present API that could be used for that, but perhaps we could add a new
enum variant for "action" that commands it.
3. We aren't very careful about preserving the reset value of the
variable, in case it's different from the active value (which could
happen if the user did a SET and there's also a value from the
postgresql.conf file).
This seems like it just requires working a bit harder in
define_custom_variable, to reapply the reset value as well as the
current value of the variable.
Any objections to fixing that stuff, while I'm looking at it?
regards, tom lane
diff --git a/doc/src/sgml/auth-delay.sgml b/doc/src/sgml/auth-delay.sgml
index e377c980cab919a407294356f27ede0255e63897..91549ffe4f61e019645866fcd98a6f2fb2f52998 100644
*** a/doc/src/sgml/auth-delay.sgml
--- b/doc/src/sgml/auth-delay.sgml
***************
*** 42,57 ****
</variablelist>
<para>
! In order to set these parameters in your <filename>postgresql.conf</> file,
! you will need to add <literal>auth_delay</> to
! <xref linkend="guc-custom-variable-classes">. Typical usage might be:
</para>
<programlisting>
# postgresql.conf
shared_preload_libraries = 'auth_delay'
- custom_variable_classes = 'auth_delay'
auth_delay.milliseconds = '500'
</programlisting>
</sect2>
--- 42,55 ----
</variablelist>
<para>
! These parameters must be set in <filename>postgresql.conf</>.
! Typical usage might be:
</para>
<programlisting>
# postgresql.conf
shared_preload_libraries = 'auth_delay'
auth_delay.milliseconds = '500'
</programlisting>
</sect2>
diff --git a/doc/src/sgml/auto-explain.sgml b/doc/src/sgml/auto-explain.sgml
index b16f9064ffc05d86637c054bc7b38221988b11db..6a8da566fbb200da0ab30f1cee5caee113645907 100644
*** a/doc/src/sgml/auto-explain.sgml
--- b/doc/src/sgml/auto-explain.sgml
*************** LOAD 'auto_explain';
*** 158,173 ****
</variablelist>
<para>
! In order to set these parameters in your <filename>postgresql.conf</> file,
! you will need to add <literal>auto_explain</> to
! <xref linkend="guc-custom-variable-classes">. Typical usage might be:
</para>
<programlisting>
# postgresql.conf
shared_preload_libraries = 'auto_explain'
- custom_variable_classes = 'auto_explain'
auto_explain.log_min_duration = '3s'
</programlisting>
</sect2>
--- 158,171 ----
</variablelist>
<para>
! These parameters must be set in <filename>postgresql.conf</>.
! Typical usage might be:
</para>
<programlisting>
# postgresql.conf
shared_preload_libraries = 'auto_explain'
auto_explain.log_min_duration = '3s'
</programlisting>
</sect2>
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 3282ab4f20303a986b6057c59a4bb979e20d497a..fbcd455694bfee1a17b8ebcc6d2ac504a09d0833 100644
*** a/doc/src/sgml/config.sgml
--- b/doc/src/sgml/config.sgml
*************** dynamic_library_path = 'C:\tools\postgre
*** 5940,5997 ****
<para>
This feature was designed to allow parameters not normally known to
<productname>PostgreSQL</productname> to be added by add-on modules
! (such as procedural languages). This allows add-on modules to be
configured in the standard ways.
</para>
- <variablelist>
-
- <varlistentry id="guc-custom-variable-classes" xreflabel="custom_variable_classes">
- <term><varname>custom_variable_classes</varname> (<type>string</type>)</term>
- <indexterm>
- <primary><varname>custom_variable_classes</> configuration parameter</primary>
- </indexterm>
- <listitem>
- <para>
- This variable specifies one or several class names to be used for
- custom variables, in the form of a comma-separated list. A custom
- variable is a variable not normally known
- to <productname>PostgreSQL</productname> proper but used by some
- add-on module. Such variables must have names consisting of a class
- name, a dot, and a variable name. <varname>custom_variable_classes</>
- specifies all the class names in use in a particular installation.
- This parameter can only be set in the <filename>postgresql.conf</>
- file or on the server command line.
- </para>
-
- </listitem>
- </varlistentry>
- </variablelist>
-
<para>
! The difficulty with setting custom variables in
! <filename>postgresql.conf</> is that the file must be read before add-on
! modules have been loaded, and so custom variables would ordinarily be
! rejected as unknown. When <varname>custom_variable_classes</> is set,
! the server will accept definitions of arbitrary variables within each
! specified class. These variables will be treated as placeholders and
! will have no function until the module that defines them is loaded. When a
! module for a specific class is loaded, it will add the proper variable
! definitions for its class name, convert any placeholder
! values according to those definitions, and issue warnings for any
! unrecognized placeholders of its class that remain.
</para>
<para>
! Here is an example of what <filename>postgresql.conf</> might contain
! when using custom variables:
!
! <programlisting>
! custom_variable_classes = 'plpgsql,plperl'
! plpgsql.variable_conflict = use_variable
! plperl.use_strict = true
! plruby.use_strict = true # generates error: unknown class name
! </programlisting>
</para>
</sect1>
--- 5940,5964 ----
<para>
This feature was designed to allow parameters not normally known to
<productname>PostgreSQL</productname> to be added by add-on modules
! (such as procedural languages). This allows extension modules to be
configured in the standard ways.
</para>
<para>
! Custom options have two-part names: an extension name, then a dot, then
! the parameter name proper, much like qualified names in SQL. An example
! is <literal>plpgsql.variable_conflict</>.
</para>
<para>
! Because custom options may need to be set in processes that have not
! loaded the relevant extension module, <productname>PostgreSQL</>
! will accept a setting for any two-part parameter name. Such variables
! are treated as placeholders and have no function until the module that
! defines them is loaded. When an extension module is loaded, it will add
! its variable definitions, convert any placeholder values according to
! those definitions, and issue warnings for any unrecognized placeholders
! that begin with its extension name.
</para>
</sect1>
diff --git a/doc/src/sgml/pgstatstatements.sgml b/doc/src/sgml/pgstatstatements.sgml
index 52268c545d74a5baf8c601705dec66d82711c8a6..5a0230c428618b53069f6b2f38e2d4acdcdaebff 100644
*** a/doc/src/sgml/pgstatstatements.sgml
--- b/doc/src/sgml/pgstatstatements.sgml
***************
*** 275,290 ****
</para>
<para>
! In order to set any of these parameters in your
! <filename>postgresql.conf</> file,
! you will need to add <literal>pg_stat_statements</> to
! <xref linkend="guc-custom-variable-classes">. Typical usage might be:
<programlisting>
# postgresql.conf
shared_preload_libraries = 'pg_stat_statements'
- custom_variable_classes = 'pg_stat_statements'
pg_stat_statements.max = 10000
pg_stat_statements.track = all
</programlisting>
--- 275,287 ----
</para>
<para>
! These parameters must be set in <filename>postgresql.conf</>.
! Typical usage might be:
<programlisting>
# postgresql.conf
shared_preload_libraries = 'pg_stat_statements'
pg_stat_statements.max = 10000
pg_stat_statements.track = all
</programlisting>
diff --git a/doc/src/sgml/plperl.sgml b/doc/src/sgml/plperl.sgml
index b957757da64685450b5961a2ddc7c114c3dd3336..81b6de7adb67bd76c0a317e878833536f55913e8 100644
*** a/doc/src/sgml/plperl.sgml
--- b/doc/src/sgml/plperl.sgml
*************** CREATE TRIGGER test_valid_id_trig
*** 1219,1228 ****
<para>
This section lists configuration parameters that affect <application>PL/Perl</>.
- To set any of these parameters before <application>PL/Perl</> has been loaded,
- it is necessary to have added <quote><literal>plperl</></> to the
- <xref linkend="guc-custom-variable-classes"> list in
- <filename>postgresql.conf</filename>.
</para>
<variablelist>
--- 1219,1224 ----
diff --git a/doc/src/sgml/plpgsql.sgml b/doc/src/sgml/plpgsql.sgml
index 84fb012d1f3942914f12445807f9e6c0aa62eaa9..c14c34cd322488bc326b3e703d8060f9f3371599 100644
*** a/doc/src/sgml/plpgsql.sgml
--- b/doc/src/sgml/plpgsql.sgml
*************** BEGIN
*** 4007,4017 ****
<literal>use_column</> (where <literal>error</> is the factory default).
This parameter affects subsequent compilations
of statements in <application>PL/pgSQL</> functions, but not statements
! already compiled in the current session. To set the parameter before
! <application>PL/pgSQL</> has been loaded, it is necessary to have added
! <quote><literal>plpgsql</></> to the <xref
! linkend="guc-custom-variable-classes"> list in
! <filename>postgresql.conf</filename>. Because changing this setting
can cause unexpected changes in the behavior of <application>PL/pgSQL</>
functions, it can only be changed by a superuser.
</para>
--- 4007,4014 ----
<literal>use_column</> (where <literal>error</> is the factory default).
This parameter affects subsequent compilations
of statements in <application>PL/pgSQL</> functions, but not statements
! already compiled in the current session.
! Because changing this setting
can cause unexpected changes in the behavior of <application>PL/pgSQL</>
functions, it can only be changed by a superuser.
</para>
diff --git a/src/backend/utils/misc/guc-file.l b/src/backend/utils/misc/guc-file.l
index a7cf0378dca25f23c3dfed987c088663769e2bf5..7728544c5452650187e242d06d7b6c3353ef99d5 100644
*** a/src/backend/utils/misc/guc-file.l
--- b/src/backend/utils/misc/guc-file.l
*************** ProcessConfigFile(GucContext context)
*** 111,118 ****
ConfigVariable *item,
*head,
*tail;
- char *cvc = NULL;
- struct config_string *cvc_struct;
int i;
/*
--- 111,116 ----
*************** ProcessConfigFile(GucContext context)
*** 139,188 ****
}
/*
- * We need the proposed new value of custom_variable_classes to check
- * custom variables with. ParseConfigFile ensured that if it's in
- * the file, it's first in the list. But first check to see if we
- * have an active value from the command line, which should override
- * the file in any case. (Since there's no relevant env var, the
- * only possible nondefault sources are the file and ARGV.)
- */
- cvc_struct = (struct config_string *)
- find_option("custom_variable_classes", false, elevel);
- Assert(cvc_struct);
- if (cvc_struct->gen.reset_source > PGC_S_FILE)
- {
- cvc = guc_strdup(elevel, cvc_struct->reset_val);
- if (cvc == NULL)
- {
- error = true;
- goto cleanup_list;
- }
- }
- else if (head != NULL &&
- guc_name_compare(head->name, "custom_variable_classes") == 0)
- {
- /*
- * Need to canonicalize the value by calling the check hook.
- */
- void *extra = NULL;
-
- cvc = guc_strdup(elevel, head->value);
- if (cvc == NULL)
- {
- error = true;
- goto cleanup_list;
- }
- if (!call_string_check_hook(cvc_struct, &cvc, &extra,
- PGC_S_FILE, elevel))
- {
- error = true;
- goto cleanup_list;
- }
- if (extra)
- free(extra);
- }
-
- /*
* Mark all extant GUC variables as not present in the config file.
* We need this so that we can tell below which ones have been removed
* from the file since we last processed it.
--- 137,142 ----
*************** ProcessConfigFile(GucContext context)
*** 199,237 ****
* quasi-syntactic check on the validity of the config file. It is
* important that the postmaster and all backends agree on the results
* of this phase, else we will have strange inconsistencies about which
! * processes accept a config file update and which don't. Hence, custom
! * variable names can only be checked against custom_variable_classes,
! * not against any loadable modules that might (or might not) be present.
! * Likewise, we don't attempt to validate the options' values here.
*
* In addition, the GUC_IS_IN_FILE flag is set on each existing GUC
* variable mentioned in the file.
*/
for (item = head; item; item = item->next)
{
- char *sep = strchr(item->name, GUC_QUALIFIER_SEPARATOR);
struct config_generic *record;
! if (sep)
! {
! /* Custom variable, so check against custom_variable_classes */
! if (!is_custom_class(item->name, sep - item->name, cvc))
! {
! ereport(elevel,
! (errcode(ERRCODE_UNDEFINED_OBJECT),
! errmsg("unrecognized configuration parameter \"%s\" in file \"%s\" line %u",
! item->name,
! item->filename, item->sourceline)));
! error = true;
! continue;
! }
! }
!
record = find_option(item->name, false, elevel);
if (record)
record->status |= GUC_IS_IN_FILE;
! else if (!sep)
{
/* Invalid non-custom variable, so complain */
ereport(elevel,
--- 153,181 ----
* quasi-syntactic check on the validity of the config file. It is
* important that the postmaster and all backends agree on the results
* of this phase, else we will have strange inconsistencies about which
! * processes accept a config file update and which don't. Hence, unknown
! * custom variable names have to be accepted without complaint. For the
! * same reason, we don't attempt to validate the options' values here.
*
* In addition, the GUC_IS_IN_FILE flag is set on each existing GUC
* variable mentioned in the file.
*/
for (item = head; item; item = item->next)
{
struct config_generic *record;
! /*
! * Try to find the variable; but do not create a custom placeholder
! * if it's not there already.
! */
record = find_option(item->name, false, elevel);
if (record)
+ {
+ /* Found, so mark it as present in file */
record->status |= GUC_IS_IN_FILE;
! }
! else if (strchr(item->name, GUC_QUALIFIER_SEPARATOR) == NULL)
{
/* Invalid non-custom variable, so complain */
ereport(elevel,
*************** ProcessConfigFile(GucContext context)
*** 382,389 ****
cleanup_list:
FreeConfigVariables(head);
- if (cvc)
- free(cvc);
if (error)
{
--- 326,331 ----
*************** ParseConfigFp(FILE *fp, const char *conf
*** 581,620 ****
pfree(opt_name);
pfree(opt_value);
}
- else if (guc_name_compare(opt_name, "custom_variable_classes") == 0)
- {
- /*
- * This variable must be processed first as it controls
- * the validity of other variables; so it goes at the head
- * of the result list. If we already found a value for it,
- * replace with this one.
- */
- item = *head_p;
- if (item != NULL &&
- guc_name_compare(item->name, "custom_variable_classes") == 0)
- {
- /* replace existing head item */
- pfree(item->name);
- pfree(item->value);
- item->name = opt_name;
- item->value = opt_value;
- item->filename = pstrdup(config_file);
- item->sourceline = ConfigFileLineno-1;
- }
- else
- {
- /* prepend to list */
- item = palloc(sizeof *item);
- item->name = opt_name;
- item->value = opt_value;
- item->filename = pstrdup(config_file);
- item->sourceline = ConfigFileLineno-1;
- item->next = *head_p;
- *head_p = item;
- if (*tail_p == NULL)
- *tail_p = item;
- }
- }
else
{
/* ordinary variable, append to list */
--- 523,528 ----
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index c5b14522d5fb0eec8beb545164727f128d716cd0..2fd4867d253ca97f1c1d10a31686f450a289b48e 100644
*** a/src/backend/utils/misc/guc.c
--- b/src/backend/utils/misc/guc.c
*************** static void assign_syslog_ident(const ch
*** 178,184 ****
static void assign_session_replication_role(int newval, void *extra);
static bool check_temp_buffers(int *newval, void **extra, GucSource source);
static bool check_phony_autocommit(bool *newval, void **extra, GucSource source);
- static bool check_custom_variable_classes(char **newval, void **extra, GucSource source);
static bool check_debug_assertions(bool *newval, void **extra, GucSource source);
static bool check_bonjour(bool *newval, void **extra, GucSource source);
static bool check_ssl(bool *newval, void **extra, GucSource source);
--- 178,183 ----
*************** static char *log_timezone_string;
*** 467,473 ****
static char *timezone_abbreviations_string;
static char *XactIsoLevel_string;
static char *session_authorization_string;
- static char *custom_variable_classes;
static int max_function_args;
static int max_index_keys;
static int max_identifier_length;
--- 466,471 ----
*************** static struct config_string ConfigureNam
*** 2886,2902 ****
},
{
- {"custom_variable_classes", PGC_SIGHUP, CUSTOM_OPTIONS,
- gettext_noop("Sets the list of known custom variable classes."),
- NULL,
- GUC_LIST_INPUT | GUC_LIST_QUOTE
- },
- &custom_variable_classes,
- NULL,
- check_custom_variable_classes, NULL, NULL
- },
-
- {
{"data_directory", PGC_POSTMASTER, FILE_LOCATIONS,
gettext_noop("Sets the server's data directory."),
NULL,
--- 2884,2889 ----
*************** add_guc_variable(struct config_generic *
*** 3623,3630 ****
}
/*
! * Create and add a placeholder variable. It's presumed to belong
! * to a valid custom variable class at this point.
*/
static struct config_generic *
add_placeholder_variable(const char *name, int elevel)
--- 3610,3616 ----
}
/*
! * Create and add a placeholder variable for a custom variable name.
*/
static struct config_generic *
add_placeholder_variable(const char *name, int elevel)
*************** add_placeholder_variable(const char *nam
*** 3670,3711 ****
}
/*
- * Detect whether the portion of "name" before dotPos matches any custom
- * variable class name listed in custom_var_classes. The latter must be
- * formatted the way that assign_custom_variable_classes does it, ie,
- * no whitespace. NULL is valid for custom_var_classes.
- */
- static bool
- is_custom_class(const char *name, int dotPos, const char *custom_var_classes)
- {
- bool result = false;
- const char *ccs = custom_var_classes;
-
- if (ccs != NULL)
- {
- const char *start = ccs;
-
- for (;; ++ccs)
- {
- char c = *ccs;
-
- if (c == '\0' || c == ',')
- {
- if (dotPos == ccs - start && strncmp(start, name, dotPos) == 0)
- {
- result = true;
- break;
- }
- if (c == '\0')
- break;
- start = ccs + 1;
- }
- }
- }
- return result;
- }
-
- /*
* Look up option NAME. If it exists, return a pointer to its record,
* else return NULL. If create_placeholders is TRUE, we'll create a
* placeholder record for a valid-looking custom variable name.
--- 3656,3661 ----
*************** find_option(const char *name, bool creat
*** 3745,3757 ****
if (create_placeholders)
{
/*
! * Check if the name is qualified, and if so, check if the qualifier
! * matches any custom variable class. If so, add a placeholder.
*/
! const char *dot = strchr(name, GUC_QUALIFIER_SEPARATOR);
!
! if (dot != NULL &&
! is_custom_class(name, dot - name, custom_variable_classes))
return add_placeholder_variable(name, elevel);
}
--- 3695,3703 ----
if (create_placeholders)
{
/*
! * Check if the name is qualified, and if so, add a placeholder.
*/
! if (strchr(name, GUC_QUALIFIER_SEPARATOR) != NULL)
return add_placeholder_variable(name, elevel);
}
*************** write_nondefault_variables(GucContext co
*** 7406,7412 ****
{
int elevel;
FILE *fp;
- struct config_generic *cvc_conf;
int i;
Assert(context == PGC_POSTMASTER || context == PGC_SIGHUP);
--- 7352,7357 ----
*************** write_nondefault_variables(GucContext co
*** 7426,7445 ****
return;
}
- /*
- * custom_variable_classes must be written out first; otherwise we might
- * reject custom variable values while reading the file.
- */
- cvc_conf = find_option("custom_variable_classes", false, ERROR);
- if (cvc_conf)
- write_one_nondefault_variable(fp, cvc_conf);
-
for (i = 0; i < num_guc_variables; i++)
{
! struct config_generic *gconf = guc_variables[i];
!
! if (gconf != cvc_conf)
! write_one_nondefault_variable(fp, gconf);
}
if (FreeFile(fp))
--- 7371,7379 ----
return;
}
for (i = 0; i < num_guc_variables; i++)
{
! write_one_nondefault_variable(fp, guc_variables[i]);
}
if (FreeFile(fp))
*************** validate_option_array_item(const char *n
*** 7886,7905 ****
* permissions normally (ie, allow if variable is USERSET, or if it's
* SUSET and user is superuser).
*
! * name is not known, but exists or can be created as a placeholder
! * (implying it has a prefix listed in custom_variable_classes). We allow
! * this case if you're a superuser, otherwise not. Superusers are assumed
! * to know what they're doing. We can't allow it for other users, because
! * when the placeholder is resolved it might turn out to be a SUSET
! * variable; define_custom_variable assumes we checked that.
*
* name is not known and can't be created as a placeholder. Throw error,
! * unless skipIfNoPermissions is true, in which case return FALSE. (It's
! * tempting to allow this case to superusers, if the name is qualified but
! * not listed in custom_variable_classes. That would ease restoring of
! * dumps containing ALTER ROLE/DATABASE SET. However, it's not clear that
! * this usage justifies such a loss of error checking. You can always fix
! * custom_variable_classes before you restore.)
*/
gconf = find_option(name, true, WARNING);
if (!gconf)
--- 7820,7834 ----
* permissions normally (ie, allow if variable is USERSET, or if it's
* SUSET and user is superuser).
*
! * name is not known, but exists or can be created as a placeholder (i.e.,
! * it has a prefixed name). We allow this case if you're a superuser,
! * otherwise not. Superusers are assumed to know what they're doing.
! * We can't allow it for other users, because when the placeholder is
! * resolved it might turn out to be a SUSET variable;
! * define_custom_variable assumes we checked that.
*
* name is not known and can't be created as a placeholder. Throw error,
! * unless skipIfNoPermissions is true, in which case return FALSE.
*/
gconf = find_option(name, true, WARNING);
if (!gconf)
*************** validate_option_array_item(const char *n
*** 7909,7915 ****
return false;
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
! errmsg("unrecognized configuration parameter \"%s\"", name)));
}
if (gconf->flags & GUC_CUSTOM_PLACEHOLDER)
--- 7838,7845 ----
return false;
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
! errmsg("unrecognized configuration parameter \"%s\"",
! name)));
}
if (gconf->flags & GUC_CUSTOM_PLACEHOLDER)
*************** check_phony_autocommit(bool *newval, voi
*** 8263,8331 ****
}
static bool
- check_custom_variable_classes(char **newval, void **extra, GucSource source)
- {
- /*
- * Check syntax. newval must be a comma separated list of identifiers.
- * Whitespace is allowed but removed from the result.
- */
- bool hasSpaceAfterToken = false;
- const char *cp = *newval;
- int symLen = 0;
- char c;
- StringInfoData buf;
-
- /* Default NULL is OK */
- if (cp == NULL)
- return true;
-
- initStringInfo(&buf);
- while ((c = *cp++) != '\0')
- {
- if (isspace((unsigned char) c))
- {
- if (symLen > 0)
- hasSpaceAfterToken = true;
- continue;
- }
-
- if (c == ',')
- {
- if (symLen > 0) /* terminate identifier */
- {
- appendStringInfoChar(&buf, ',');
- symLen = 0;
- }
- hasSpaceAfterToken = false;
- continue;
- }
-
- if (hasSpaceAfterToken || !(isalnum((unsigned char) c) || c == '_'))
- {
- /*
- * Syntax error due to token following space after token or
- * non-identifier character
- */
- pfree(buf.data);
- return false;
- }
- appendStringInfoChar(&buf, c);
- symLen++;
- }
-
- /* Remove stray ',' at end */
- if (symLen == 0 && buf.len > 0)
- buf.data[--buf.len] = '\0';
-
- /* GUC wants the result malloc'd */
- free(*newval);
- *newval = guc_strdup(LOG, buf.data);
-
- pfree(buf.data);
- return true;
- }
-
- static bool
check_debug_assertions(bool *newval, void **extra, GucSource source)
{
#ifndef USE_ASSERT_CHECKING
--- 8193,8198 ----
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index a18f14ae253a432f4386682d2bcd55d61fd9dba3..5bb7e7117bc95c5cf1ba2bd312c707f4208999c5 100644
*** a/src/backend/utils/misc/postgresql.conf.sample
--- b/src/backend/utils/misc/postgresql.conf.sample
***************
*** 560,563 ****
# CUSTOMIZED OPTIONS
#------------------------------------------------------------------------------
! #custom_variable_classes = '' # list of custom variable class names
--- 560,563 ----
# CUSTOMIZED OPTIONS
#------------------------------------------------------------------------------
! # Add settings for extensions here
diff --git a/src/pl/plperl/expected/plperl_init.out b/src/pl/plperl/expected/plperl_init.out
index 4a04dbd6f37d43fab912206c1dd23ea89d0be11d..e8a8e9bd83d6dff6c034d154965c86be55b1303d 100644
*** a/src/pl/plperl/expected/plperl_init.out
--- b/src/pl/plperl/expected/plperl_init.out
***************
*** 1,5 ****
-- test plperl.on_plperl_init errors are fatal
! -- Avoid need for custom_variable_classes = 'plperl'
LOAD 'plperl';
SET SESSION plperl.on_plperl_init = ' system("/nonesuch") ';
SHOW plperl.on_plperl_init;
--- 1,5 ----
-- test plperl.on_plperl_init errors are fatal
! -- Must load plperl before we can set on_plperl_init
LOAD 'plperl';
SET SESSION plperl.on_plperl_init = ' system("/nonesuch") ';
SHOW plperl.on_plperl_init;
diff --git a/src/pl/plperl/expected/plperl_shared.out b/src/pl/plperl/expected/plperl_shared.out
index 1a6bf5ee4d42eba0492cfca5c7dee8ad6af321b8..67478ab454b4176955ca36e236edfd704222972b 100644
*** a/src/pl/plperl/expected/plperl_shared.out
--- b/src/pl/plperl/expected/plperl_shared.out
***************
*** 1,6 ****
-- test plperl.on_plperl_init via the shared hash
-- (must be done before plperl is first used)
! -- Avoid need for custom_variable_classes = 'plperl'
LOAD 'plperl';
-- testing on_plperl_init gets run, and that it can alter %_SHARED
SET plperl.on_plperl_init = '$_SHARED{on_init} = 42';
--- 1,6 ----
-- test plperl.on_plperl_init via the shared hash
-- (must be done before plperl is first used)
! -- Must load plperl before we can set on_plperl_init
LOAD 'plperl';
-- testing on_plperl_init gets run, and that it can alter %_SHARED
SET plperl.on_plperl_init = '$_SHARED{on_init} = 42';
diff --git a/src/pl/plperl/expected/plperlu.out b/src/pl/plperl/expected/plperlu.out
index 25ac007b7a27b71558356c37adb2e2e9856b87b4..1ba07eed9dc835579e52bc50217075f64991dbbc 100644
*** a/src/pl/plperl/expected/plperlu.out
--- b/src/pl/plperl/expected/plperlu.out
***************
*** 1,6 ****
-- Use ONLY plperlu tests here. For plperl/plerlu combined tests
-- see plperl_plperlu.sql
! -- Avoid need for custom_variable_classes = 'plperl'
LOAD 'plperl';
-- Test plperl.on_plperlu_init gets run
SET plperl.on_plperlu_init = '$_SHARED{init} = 42';
--- 1,6 ----
-- Use ONLY plperlu tests here. For plperl/plerlu combined tests
-- see plperl_plperlu.sql
! -- Must load plperl before we can set on_plperlu_init
LOAD 'plperl';
-- Test plperl.on_plperlu_init gets run
SET plperl.on_plperlu_init = '$_SHARED{init} = 42';
diff --git a/src/pl/plperl/sql/plperl_init.sql b/src/pl/plperl/sql/plperl_init.sql
index f6a32b9bae4792ab449ef62cdb717384adca6bd8..51ac9192bdfc4f77c08a841f0106304ee34e9e56 100644
*** a/src/pl/plperl/sql/plperl_init.sql
--- b/src/pl/plperl/sql/plperl_init.sql
***************
*** 1,6 ****
-- test plperl.on_plperl_init errors are fatal
! -- Avoid need for custom_variable_classes = 'plperl'
LOAD 'plperl';
SET SESSION plperl.on_plperl_init = ' system("/nonesuch") ';
--- 1,6 ----
-- test plperl.on_plperl_init errors are fatal
! -- Must load plperl before we can set on_plperl_init
LOAD 'plperl';
SET SESSION plperl.on_plperl_init = ' system("/nonesuch") ';
diff --git a/src/pl/plperl/sql/plperl_shared.sql b/src/pl/plperl/sql/plperl_shared.sql
index d367d32ff08266f9b0f1f558e704e785fd3420ec..d2fa8cbf93e7b7f63c49984b1432a93de65089a7 100644
*** a/src/pl/plperl/sql/plperl_shared.sql
--- b/src/pl/plperl/sql/plperl_shared.sql
***************
*** 1,7 ****
-- test plperl.on_plperl_init via the shared hash
-- (must be done before plperl is first used)
! -- Avoid need for custom_variable_classes = 'plperl'
LOAD 'plperl';
-- testing on_plperl_init gets run, and that it can alter %_SHARED
--- 1,7 ----
-- test plperl.on_plperl_init via the shared hash
-- (must be done before plperl is first used)
! -- Must load plperl before we can set on_plperl_init
LOAD 'plperl';
-- testing on_plperl_init gets run, and that it can alter %_SHARED
diff --git a/src/pl/plperl/sql/plperlu.sql b/src/pl/plperl/sql/plperlu.sql
index 125691e5f7ba7bad01aae0a7c71a20c251e9c69e..831b8f44604e1829e058394fed9c67ccf6e75c7f 100644
*** a/src/pl/plperl/sql/plperlu.sql
--- b/src/pl/plperl/sql/plperlu.sql
***************
*** 1,7 ****
-- Use ONLY plperlu tests here. For plperl/plerlu combined tests
-- see plperl_plperlu.sql
! -- Avoid need for custom_variable_classes = 'plperl'
LOAD 'plperl';
-- Test plperl.on_plperlu_init gets run
--- 1,7 ----
-- Use ONLY plperlu tests here. For plperl/plerlu combined tests
-- see plperl_plperlu.sql
! -- Must load plperl before we can set on_plperlu_init
LOAD 'plperl';
-- Test plperl.on_plperlu_init gets run
Tom Lane <tgl@sss.pgh.pa.us> writes: > Simon Riggs <simon@2ndQuadrant.com> writes: >> On Sun, Oct 2, 2011 at 10:05 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote: >>> So at this point I'd vote for just dropping it and always allowing >>> custom (that is, qualified) GUC names to be set, whether the prefix >>> corresponds to any loaded module or not. > >> Sounds sensible. One less thing to configure is a good thing. > > Attached is a draft patch for that. I fiddled with custom_variable_classes for the extension's patch, the idea was to be able to append to it from the control file. Removing it entirely makes it even simpler. I think we should load any qualified entry in the control file as a custom GUC, or allow a new extension.conf file to be given containing the default values. > While working on this I got annoyed at our cheesy handling of the > situation where a "placeholder" value has to be turned into a real > setting, which happens when the corresponding extension gets loaded. > There are several issues: > > 1. If it's a SUSET variable, a preceding attempt to set the value via > SET will fail even if you're a superuser, for example > > regression=# set plpgsql.variable_conflict = use_variable; > SET > regression=# load 'plpgsql'; > ERROR: permission denied to set parameter "plpgsql.variable_conflict" > > The reason for that is that define_custom_variable doesn't know whether > the pre-existing value was set by a superuser, so it must assume the > worst. Seems like we could easily fix that by having set_config_option > set a flag in the GUC variable noting whether a SET was done by a > superuser or not. I managed to do that by having another specific GUC array so that I could call the GUC validation code (assign hooks) at module loading time. I guess a new flag would provide same capabilities. > 2. If you do get an error while re-assigning the pre-existing value of > the variable, it's thrown as an ERROR. This is really pretty nasty > because it'll abort execution of the extension module's init function; > for example, a likely consequence is that other custom variables of > the module don't set set up correctly, and it could easily be a lot > worse if there are other things the init function hasn't done yet. > > I think we need to arrange that set_config_option only reports failures > to apply such values as WARNING, not ERROR. There isn't anything in its > present API that could be used for that, but perhaps we could add a new > enum variant for "action" that commands it. I think this behavior only makes sense when we had a previous default value before loading the module (set in the main postgresql.conf file), and that we should still ERROR out otherwise (default provided by the extension's code itself). Or maybe I'm confused now. > 3. We aren't very careful about preserving the reset value of the > variable, in case it's different from the active value (which could > happen if the user did a SET and there's also a value from the > postgresql.conf file). > > This seems like it just requires working a bit harder in > define_custom_variable, to reapply the reset value as well as the > current value of the variable. > > Any objections to fixing that stuff, while I'm looking at it? Please do :) Regards, -- Dimitri Fontaine http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support
On Sun, Oct 2, 2011 at 23:05, Tom Lane <tgl@sss.pgh.pa.us> wrote: > During the discussion of Alexey Klyukin's rewrite of ParseConfigFile, > considerable unhappiness was expressed by various people about the > complexity and relative uselessness of the custom_variable_classes GUC. > While working over his patch just now, I've come around to the side that > was saying that this variable isn't worth its keep. We don't have any > way to validate whether the second part of a qualified GUC name is > correct, if its associated extension module isn't loaded, so how much > point is there in validating the first part? And the variable is > certainly a pain in the rear both to DBAs and to the GUC code itself. Don't forget that there are usecases for variables under custom_variable_classes that aren't actually associated with extensions (as general session-shared-variables). Though I guess if it was somehow restricted to extensions, those who needed that could just rewrap all their code as extensions - though that would make it less convenient. The point being that even if you *could* validate them somehow against a static list, requiring that might not be a good idea. > So at this point I'd vote for just dropping it and always allowing > custom (that is, qualified) GUC names to be set, whether the prefix > corresponds to any loaded module or not. Seems reasonable to me. -- Magnus Hagander Me: http://www.hagander.net/ Work: http://www.redpill-linpro.com/
Magnus Hagander <magnus@hagander.net> writes:
> Don't forget that there are usecases for variables under
> custom_variable_classes that aren't actually associated with
> extensions (as general session-shared-variables). Though I guess if it
> was somehow restricted to extensions, those who needed that could just
> rewrap all their code as extensions - though that would make it less
> convenient.
Right. Getting rid of custom_variable_classes should actually make
those use-cases easier, since it will eliminate a required setup step.
I tried to think of a security argument for keeping the setting, but
couldn't really. Yeah, not having it will let people clutter their
individual backend's GUC array with lots of useless stuff, but so what?
There's plenty of other ways to run your session out of memory if you're
so inclined.
regards, tom lane
On 10/03/2011 10:17 AM, Tom Lane wrote: > Magnus Hagander<magnus@hagander.net> writes: >> Don't forget that there are usecases for variables under >> custom_variable_classes that aren't actually associated with >> extensions (as general session-shared-variables). Though I guess if it >> was somehow restricted to extensions, those who needed that could just >> rewrap all their code as extensions - though that would make it less >> convenient. > Right. Getting rid of custom_variable_classes should actually make > those use-cases easier, since it will eliminate a required setup step. > > I tried to think of a security argument for keeping the setting, but > couldn't really. Yeah, not having it will let people clutter their > individual backend's GUC array with lots of useless stuff, but so what? > There's plenty of other ways to run your session out of memory if you're > so inclined. > > So are we going to sanction using this as a poor man's session variable mechanism? If so maybe we should at least warn that anything set will be accessible by all roles, so security definer functions for example should be wary of trusting such values. cheers andrew
Andrew Dunstan <andrew@dunslane.net> writes:
> On 10/03/2011 10:17 AM, Tom Lane wrote:
>> Right. Getting rid of custom_variable_classes should actually make
>> those use-cases easier, since it will eliminate a required setup step.
> So are we going to sanction using this as a poor man's session variable
> mechanism?
People already are doing that, sanctioned or not.
> If so maybe we should at least warn that anything set will be accessible
> by all roles, so security definer functions for example should be wary
> of trusting such values.
Since it's not documented anywhere, I'm not sure where we'd put such
a warning. I think anyone bright enough to think of such a hack should
be able to see the potential downsides, anyway.
regards, tom lane
On Mon, Oct 03, 2011 at 10:41:48AM -0400, Tom Lane wrote: > Andrew Dunstan <andrew@dunslane.net> writes: > > On 10/03/2011 10:17 AM, Tom Lane wrote: > >> Right. Getting rid of custom_variable_classes should actually > >> make those use-cases easier, since it will eliminate a required > >> setup step. > > > So are we going to sanction using this as a poor man's session > > variable mechanism? > > People already are doing that, sanctioned or not. > > > If so maybe we should at least warn that anything set will be > > accessible by all roles, so security definer functions for example > > should be wary of trusting such values. > > Since it's not documented anywhere, I'm not sure where we'd put such > a warning. I think anyone bright enough to think of such a hack > should be able to see the potential downsides, anyway. Perhaps it's best to document this usage and include the warning for those less "bright," as you term them. I'd be less tempted to call them "not bright" and more tempted to think they might assume PostgreSQL already takes care of cleaning this up, but whatever. Cheers, David. -- David Fetter <david@fetter.org> http://fetter.org/ Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter Skype: davidfetter XMPP: david.fetter@gmail.com iCal: webcal://www.tripit.com/feed/ical/people/david74/tripit.ics Remember to vote! Consider donating to Postgres: http://www.postgresql.org/about/donate
On Mon, Oct 3, 2011 at 10:55 AM, David Fetter <david@fetter.org> wrote: > Perhaps it's best to document this usage and include the warning for > those less "bright," as you term them. I'd be less tempted to call > them "not bright" and more tempted to think they might assume > PostgreSQL already takes care of cleaning this up, but whatever. Yeah. custom_variable_classes is a pretty annoying wart, but if it's set to the default value (namely, empty) then it actually does prevent people from setting bajillions of completely pointless settings, which seems like it has some merit. I'm not sure it has enough merit to justify keeping it around, but it has more than none. We could allow entering a date of February 31st, too, but we don't. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
Robert Haas <robertmhaas@gmail.com> writes:
> Yeah. custom_variable_classes is a pretty annoying wart, but if it's
> set to the default value (namely, empty) then it actually does prevent
> people from setting bajillions of completely pointless settings, which
> seems like it has some merit. I'm not sure it has enough merit to
> justify keeping it around, but it has more than none. We could allow
> entering a date of February 31st, too, but we don't.
Well, that argument was essentially why we put it in to begin with.
But I think pretty much everybody agrees that it's more trouble than
it's worth (in fact, weren't you one of the people complaining about
it?)
regards, tom lane
On Mon, Oct 3, 2011 at 11:16 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote: > Robert Haas <robertmhaas@gmail.com> writes: >> Yeah. custom_variable_classes is a pretty annoying wart, but if it's >> set to the default value (namely, empty) then it actually does prevent >> people from setting bajillions of completely pointless settings, which >> seems like it has some merit. I'm not sure it has enough merit to >> justify keeping it around, but it has more than none. We could allow >> entering a date of February 31st, too, but we don't. > > Well, that argument was essentially why we put it in to begin with. > But I think pretty much everybody agrees that it's more trouble than > it's worth (in fact, weren't you one of the people complaining about > it?) Well, yes. But I was arguing that we should replace the leaky dam with one that's watertight, rather than demolishing the dam. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
Robert Haas <robertmhaas@gmail.com> writes:
> On Mon, Oct 3, 2011 at 11:16 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Robert Haas <robertmhaas@gmail.com> writes:
>>> Yeah. �custom_variable_classes is a pretty annoying wart, but if it's
>>> set to the default value (namely, empty) then it actually does prevent
>>> people from setting bajillions of completely pointless settings, which
>>> seems like it has some merit.
>> Well, that argument was essentially why we put it in to begin with.
>> But I think pretty much everybody agrees that it's more trouble than
>> it's worth (in fact, weren't you one of the people complaining about
>> it?)
> Well, yes. But I was arguing that we should replace the leaky dam
> with one that's watertight, rather than demolishing the dam.
If we had some idea how to do that, I'd probably agree. But we don't.
In any case, custom_variable_classes as currently defined is not the
basis for a solution to that desire, and removing it won't create an
impediment to solving the problem properly, should we come up with
a solution.
(This is, however, a good reason for continuing to not document that
you can create random GUC variables --- we might someday shut that
off again.)
regards, tom lane
On Mon, Oct 3, 2011 at 12:25 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote: > Robert Haas <robertmhaas@gmail.com> writes: >> On Mon, Oct 3, 2011 at 11:16 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote: >>> Robert Haas <robertmhaas@gmail.com> writes: >>>> Yeah. custom_variable_classes is a pretty annoying wart, but if it's >>>> set to the default value (namely, empty) then it actually does prevent >>>> people from setting bajillions of completely pointless settings, which >>>> seems like it has some merit. > >>> Well, that argument was essentially why we put it in to begin with. >>> But I think pretty much everybody agrees that it's more trouble than >>> it's worth (in fact, weren't you one of the people complaining about >>> it?) > >> Well, yes. But I was arguing that we should replace the leaky dam >> with one that's watertight, rather than demolishing the dam. > > If we had some idea how to do that, I'd probably agree. But we don't. > In any case, custom_variable_classes as currently defined is not the > basis for a solution to that desire, and removing it won't create an > impediment to solving the problem properly, should we come up with > a solution. Yeah, that's why I'm not complaining too loudly. :-) > (This is, however, a good reason for continuing to not document that > you can create random GUC variables --- we might someday shut that > off again.) Or maybe better still would be to explicitly document the fact that behavior in this area should not be relied upon. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
David Fetter <david@fetter.org> writes: > Perhaps it's best to document this usage and include the warning for > those less "bright," as you term them. I'd be less tempted to call > them "not bright" and more tempted to think they might assume > PostgreSQL already takes care of cleaning this up, but whatever. Who's that dim? D'oh. Another compromise might be to allow for defining variable in any class from the configuration files but restrict that to existing classes from the SET command. Wait, that's exactly what happens as soon as there's no explicit custom_variable_classes, right? So we're talking about people with configuration file editing and reload powers, not about anyone who can connect. I think that's ok. Regards, -- Dimitri Fontaine http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support
Dimitri Fontaine <dimitri@2ndQuadrant.fr> writes:
> Another compromise might be to allow for defining variable in any class
> from the configuration files but restrict that to existing classes from
> the SET command. Wait, that's exactly what happens as soon as there's
> no explicit custom_variable_classes, right?
No, because there are people who do intentionally use placeholder
variables as session-local storage, and that would be taking away
that capability.
regards, tom lane
Tom Lane <tgl@sss.pgh.pa.us> writes: > Dimitri Fontaine <dimitri@2ndQuadrant.fr> writes: >> Another compromise might be to allow for defining variable in any class >> from the configuration files but restrict that to existing classes from >> the SET command. Wait, that's exactly what happens as soon as there's >> no explicit custom_variable_classes, right? > > No, because there are people who do intentionally use placeholder > variables as session-local storage, and that would be taking away > that capability. They would have to set the variable to its default value in some configuration file and reload, just as now. They wouldn't have to also edit custom_variable_classes, that's about it. Or do you want to open SET typo.wrogn TO 'foobar' to just work silently? Regards, -- Dimitri Fontaine http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support
Dimitri Fontaine <dimitri@2ndQuadrant.fr> writes:
> Tom Lane <tgl@sss.pgh.pa.us> writes:
>> No, because there are people who do intentionally use placeholder
>> variables as session-local storage, and that would be taking away
>> that capability.
> Or do you want to open SET typo.wrogn TO 'foobar' to just work silently?
Well, right at the moment it *does* work silently, as long as the prefix
is one you listed in custom_variable_classes. I don't think we want to
take that away, and in particular I don't want to assume that every
variable will be declared in advance. It's a fairly safe bet that there
are some apps out there that would be broken by such a requirement.
At the same time, I'd kind of like to see a facility for declaring such
variables, if only so you could define them to be bool/int/real not just
strings. But this is getting far afield from the immediate proposal,
and no I'm not volunteering to do it.
regards, tom lane
Tom Lane <tgl@sss.pgh.pa.us> writes: >> Or do you want to open SET typo.wrogn TO 'foobar' to just work silently? > > Well, right at the moment it *does* work silently, as long as the prefix > is one you listed in custom_variable_classes. I don't think we want to > take that away, and in particular I don't want to assume that every > variable will be declared in advance. It's a fairly safe bet that there > are some apps out there that would be broken by such a requirement. Fair enough I suppose. But I think we could break that requirement if we offer a good enough way out. > At the same time, I'd kind of like to see a facility for declaring such > variables, if only so you could define them to be bool/int/real not just > strings. But this is getting far afield from the immediate proposal, > and no I'm not volunteering to do it. I think we are able to handle that part when dealing with C extension's GUCs, because those are declared in the .so. We only need to add them to the control file, the only road block here used to be c_v_c. What I have in mind for extensions now that c_v_c is out would be to be able to declare any GUC in the control file, with default values, and without forcing extension to handle the GUC in its .so — I don't think we have to change the code beside removing the c_v_c checks here. In the general case, how far exposing DefineCustomBoolVariable and all at the SQL level would get us? Then you could allow the session to add any new GUC by calling that first, SET would bail out if given unknown variable. Yes, it would still break some existing applications, but I think it'd be worth it (and an easy fix too, as I guess most shared variables are going to be used in PL code, and if you ask me this code should now be an extension and the control file would then declare the GUCs). Regards, -- Dimitri Fontaine http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support
Dimitri Fontaine <dimitri@2ndQuadrant.fr> writes:
> What I have in mind for extensions now that c_v_c is out would be to be
> able to declare any GUC in the control file, with default values, and
> without forcing extension to handle the GUC in its .so — I don't think
> we have to change the code beside removing the c_v_c checks here.
What's the point of that? A value in an extension control file isn't
particularly easily accessible. You'd basically only see it when
loading the extension, and that's a scenario in which the existing
mechanism works just fine. I see no reason to break existing code
here.
regards, tom lane
Tom Lane <tgl@sss.pgh.pa.us> writes: > Dimitri Fontaine <dimitri@2ndQuadrant.fr> writes: >> What I have in mind for extensions now that c_v_c is out would be to be >> able to declare any GUC in the control file, with default values, and >> without forcing extension to handle the GUC in its .so — I don't think >> we have to change the code beside removing the c_v_c checks here. > > What's the point of that? A value in an extension control file isn't > particularly easily accessible. You'd basically only see it when > loading the extension, and that's a scenario in which the existing > mechanism works just fine. I see no reason to break existing code > here. It's not about the code behavior but user support and packaging. That the code does the right DefineCustom calls is very good, but users should be able to easily alter defaults after installing an extension. And you're right, putting the setup into the control file is not providing that. We could have some extension.conf file. Appending to postgresql.conf is not possible from a third-party package per debian's policy, so having extension/foo.conf instead would make sense here. But at this point, it's nothing you need to care right now in your patch I guess, unless you're motivated enough :) Regards, -- Dimitri Fontaine http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support
Dimitri Fontaine <dimitri@2ndQuadrant.fr> writes:
> Tom Lane <tgl@sss.pgh.pa.us> writes:
>> Dimitri Fontaine <dimitri@2ndQuadrant.fr> writes:
>>> What I have in mind for extensions now that c_v_c is out would be to be
>>> able to declare any GUC in the control file, with default values, and
>>> without forcing extension to handle the GUC in its .so — I don't think
>>> we have to change the code beside removing the c_v_c checks here.
>> What's the point of that? A value in an extension control file isn't
>> particularly easily accessible. You'd basically only see it when
>> loading the extension, and that's a scenario in which the existing
>> mechanism works just fine. I see no reason to break existing code
>> here.
> It's not about the code behavior but user support and packaging. That
> the code does the right DefineCustom calls is very good, but users
> should be able to easily alter defaults after installing an extension.
> And you're right, putting the setup into the control file is not
> providing that.
I still don't see the point. If they want to change the default
setting, they add an entry to postgresql.conf. Problem solved.
> We could have some extension.conf file. Appending to postgresql.conf is
> not possible from a third-party package per debian's policy, so having
> extension/foo.conf instead would make sense here.
This is adding even more complication to solve a non-problem.
May I remind you that a lot of people think that the default entries in
postgresql.conf for the core settings are a bad idea? Why should we
invent even more mechanism (and more conventions for users to remember)
to duplicate something of questionable value?
regards, tom lane
Tom Lane <tgl@sss.pgh.pa.us> writes: > I still don't see the point. If they want to change the default > setting, they add an entry to postgresql.conf. Problem solved. As you wish. They will have to figure the current defaults in some other way then edit the file. That's good enough for now anyway. >> We could have some extension.conf file. Appending to postgresql.conf is >> not possible from a third-party package per debian's policy, so having >> extension/foo.conf instead would make sense here. > > This is adding even more complication to solve a non-problem. Mmm. Ok. > May I remind you that a lot of people think that the default entries in > postgresql.conf for the core settings are a bad idea? Why should we > invent even more mechanism (and more conventions for users to remember) > to duplicate something of questionable value? It could be the timing when I try to sell my idea of one file per GUC, then extensions would simply add a bunch of files in there. The value of doing one GUC per file is not having to parse anything, the first non line is the value, the rest of the file free form comments. With this model, there's no new setup mechanism. But anyhow, all that can wait until after you get rid of custom_variable_classes, I think we're talking about what could happen next here, if anything. Regards, -- Dimitri Fontaine http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support
On Mon, Oct 3, 2011 at 00:05, Tom Lane <tgl@sss.pgh.pa.us> wrote: > > So at this point I'd vote for just dropping it and always allowing > custom (that is, qualified) GUC names to be set, whether the prefix > corresponds to any loaded module or not. > > Comments, other proposals? While working on E.164 telephone numbers datatype contrib module (https://github.com/commandprompt/e164/commits/guc) I've stumbled across this problem: how do I add regression tests involving the module-defined GUC option? Trying to hack postgresql.conf to include e164 in the custom_variable_classes then send it a HUP doesn't seem to be an option. But it seems that you cannot (re)set it otherwise. See: $ psql -d contrib_regression psql (9.1.0) Type "help" for help. contrib_regression=# SET e164.area_codes_format=''; ERROR: unrecognized configuration parameter "e164.area_codes_format" contrib_regression=# SET custom_variable_classes='e164'; ERROR: parameter "custom_variable_classes" cannot be changed now I wonder how/if other contrib modules ever do regression tests on their GUC options? At this rate, removing the custom_variable_classes option altogether is pretty much going to solve my problem. -- Regards, Alex