Christoph Berg <m...@debian.org> writes:
> in_hot_standby sounds very useful to have in that list.
I thought about this some more and concluded that we're blaming the
messenger. There's nothing wrong with \dconfig's filtering rule;
rather, it's the fault of the backend for mislabeling a lot of
run-time-computed values as source=PGC_S_OVERRIDE when they really
are dynamic defaults. Now in fairness, I think a lot of that code
predates the invention of PGC_S_DYNAMIC_DEFAULT, so there was not
a better way when it was written ... but there is now.
The attached draft patch makes the following changes:
* All run-time calculations of PGC_INTERNAL variables are relabeled
as PGC_S_DYNAMIC_DEFAULT. There is not any higher source value
that we'd allow to set such a variable, so this is sufficient.
(I didn't do anything about in_hot_standby, which is set through
a hack rather than via set_config_option; not sure whether we want
to do anything there, or what it should be if we do.) The net
effect of this compared to upthread examples is to hide
shared_memory_size and shared_memory_size_in_huge_pages from \dconfig.
* The auto-tune value of wal_buffers is relabeled as PGC_S_DYNAMIC_DEFAULT
if possible (but due to pre-existing hacks, we might have to force it).
This will hide that one too as long as you didn't manually set it.
* The rlimit-derived value of max_stack_depth is likewise relabeled
as PGC_S_DYNAMIC_DEFAULT, resolving the complaint Jonathan had upthread.
But now that we have a way to hide this, I'm having second thoughts
about whether we should. If you are on a platform that's forcing an
unreasonably small stack size, it'd be good if \dconfig told you so.
Could it be sane to label that value as PGC_S_DYNAMIC_DEFAULT only when
it's the limit value (2MB) and PGC_S_ENV_VAR when it's smaller?
In any case, I expect that we'd apply this patch only to HEAD, which
means that when using psql's \dconfig against a pre-v15 server,
you'd still see these settings that we're trying to hide.
That doesn't bother me too much, but maybe some would find it
confusing.
Thoughts?
regards, tom lane
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 71136b11a2..2461317ee4 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -4167,7 +4167,7 @@ ReadControlFile(void)
snprintf(wal_segsz_str, sizeof(wal_segsz_str), "%d", wal_segment_size);
SetConfigOption("wal_segment_size", wal_segsz_str, PGC_INTERNAL,
- PGC_S_OVERRIDE);
+ PGC_S_DYNAMIC_DEFAULT);
/* check and update variables dependent on wal_segment_size */
if (ConvertToXSegs(min_wal_size_mb, wal_segment_size) < 2)
@@ -4186,7 +4186,7 @@ ReadControlFile(void)
/* Make the initdb settings visible as GUC variables, too */
SetConfigOption("data_checksums", DataChecksumsEnabled() ? "yes" : "no",
- PGC_INTERNAL, PGC_S_OVERRIDE);
+ PGC_INTERNAL, PGC_S_DYNAMIC_DEFAULT);
}
/*
@@ -4343,13 +4343,22 @@ XLOGShmemSize(void)
* This isn't an amazingly clean place to do this, but we must wait till
* NBuffers has received its final value, and must do it before using the
* value of XLOGbuffers to do anything important.
+ *
+ * We prefer to report this value as PGC_S_DYNAMIC_DEFAULT. However, if
+ * the DBA explicitly set wal_buffers = -1 in the config file, then
+ * PGC_S_DYNAMIC_DEFAULT will fail to override that and we must force the
+ * matter with PGC_S_OVERRIDE.
*/
if (XLOGbuffers == -1)
{
char buf[32];
snprintf(buf, sizeof(buf), "%d", XLOGChooseNumBuffers());
- SetConfigOption("wal_buffers", buf, PGC_POSTMASTER, PGC_S_OVERRIDE);
+ SetConfigOption("wal_buffers", buf, PGC_POSTMASTER,
+ PGC_S_DYNAMIC_DEFAULT);
+ if (XLOGbuffers == -1) /* failed to apply it? */
+ SetConfigOption("wal_buffers", buf, PGC_POSTMASTER,
+ PGC_S_OVERRIDE);
}
Assert(XLOGbuffers > 0);
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 9fa8fdd4cf..9a610d41ad 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -262,7 +262,7 @@ BootstrapModeMain(int argc, char *argv[], bool check_only)
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("-X requires a power of two value between 1 MB and 1 GB")));
SetConfigOption("wal_segment_size", optarg, PGC_INTERNAL,
- PGC_S_OVERRIDE);
+ PGC_S_DYNAMIC_DEFAULT);
}
break;
case 'c':
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 3b73e26956..dde4bc25b1 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -921,7 +921,7 @@ PostmasterMain(int argc, char *argv[])
* useful to show, even if one would only expect at least PANIC. LOG
* entries are hidden.
*/
- SetConfigOption("log_min_messages", "FATAL", PGC_INTERNAL,
+ SetConfigOption("log_min_messages", "FATAL", PGC_SUSET,
PGC_S_OVERRIDE);
}
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index 26372d95b3..1a6f527051 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -334,7 +334,8 @@ InitializeShmemGUCs(void)
size_b = CalculateShmemSize(NULL);
size_mb = add_size(size_b, (1024 * 1024) - 1) / (1024 * 1024);
sprintf(buf, "%zu", size_mb);
- SetConfigOption("shared_memory_size", buf, PGC_INTERNAL, PGC_S_OVERRIDE);
+ SetConfigOption("shared_memory_size", buf,
+ PGC_INTERNAL, PGC_S_DYNAMIC_DEFAULT);
/*
* Calculate the number of huge pages required.
@@ -346,6 +347,7 @@ InitializeShmemGUCs(void)
hp_required = add_size(size_b / hp_size, 1);
sprintf(buf, "%zu", hp_required);
- SetConfigOption("shared_memory_size_in_huge_pages", buf, PGC_INTERNAL, PGC_S_OVERRIDE);
+ SetConfigOption("shared_memory_size_in_huge_pages", buf,
+ PGC_INTERNAL, PGC_S_DYNAMIC_DEFAULT);
}
}
diff --git a/src/backend/utils/init/miscinit.c b/src/backend/utils/init/miscinit.c
index ec6a61594a..b25bd0e583 100644
--- a/src/backend/utils/init/miscinit.c
+++ b/src/backend/utils/init/miscinit.c
@@ -787,7 +787,7 @@ InitializeSessionUserId(const char *rolename, Oid roleid)
PGC_BACKEND, PGC_S_OVERRIDE);
SetConfigOption("is_superuser",
AuthenticatedUserIsSuperuser ? "on" : "off",
- PGC_INTERNAL, PGC_S_OVERRIDE);
+ PGC_INTERNAL, PGC_S_DYNAMIC_DEFAULT);
ReleaseSysCache(roleTup);
}
@@ -844,7 +844,7 @@ SetSessionAuthorization(Oid userid, bool is_superuser)
SetConfigOption("is_superuser",
is_superuser ? "on" : "off",
- PGC_INTERNAL, PGC_S_OVERRIDE);
+ PGC_INTERNAL, PGC_S_DYNAMIC_DEFAULT);
}
/*
@@ -901,7 +901,7 @@ SetCurrentRoleId(Oid roleid, bool is_superuser)
SetConfigOption("is_superuser",
is_superuser ? "on" : "off",
- PGC_INTERNAL, PGC_S_OVERRIDE);
+ PGC_INTERNAL, PGC_S_DYNAMIC_DEFAULT);
}
diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c
index fa701daa26..6b9082604f 100644
--- a/src/backend/utils/init/postinit.c
+++ b/src/backend/utils/init/postinit.c
@@ -391,7 +391,7 @@ CheckMyDatabase(const char *name, bool am_superuser, bool override_allow_connect
SetDatabaseEncoding(dbform->encoding);
/* Record it as a GUC internal option, too */
SetConfigOption("server_encoding", GetDatabaseEncodingName(),
- PGC_INTERNAL, PGC_S_OVERRIDE);
+ PGC_INTERNAL, PGC_S_DYNAMIC_DEFAULT);
/* If we have no other source of client_encoding, use server encoding */
SetConfigOption("client_encoding", GetDatabaseEncodingName(),
PGC_BACKEND, PGC_S_DYNAMIC_DEFAULT);
@@ -470,8 +470,8 @@ CheckMyDatabase(const char *name, bool am_superuser, bool override_allow_connect
}
/* Make the locale settings visible as GUC variables, too */
- SetConfigOption("lc_collate", collate, PGC_INTERNAL, PGC_S_OVERRIDE);
- SetConfigOption("lc_ctype", ctype, PGC_INTERNAL, PGC_S_OVERRIDE);
+ SetConfigOption("lc_collate", collate, PGC_INTERNAL, PGC_S_DYNAMIC_DEFAULT);
+ SetConfigOption("lc_ctype", ctype, PGC_INTERNAL, PGC_S_DYNAMIC_DEFAULT);
check_strxfrm_bug();
diff --git a/src/backend/utils/misc/guc-file.l b/src/backend/utils/misc/guc-file.l
index 4360c461df..ce5633844c 100644
--- a/src/backend/utils/misc/guc-file.l
+++ b/src/backend/utils/misc/guc-file.l
@@ -401,9 +401,8 @@ ProcessConfigFileInternal(GucContext context, bool applySettings, int elevel)
* be run only after initialization is complete.
*
* XXX this is an unmaintainable crock, because we have to know how to set
- * (or at least what to call to set) every variable that could potentially
- * have PGC_S_DYNAMIC_DEFAULT or PGC_S_ENV_VAR source. However, there's no
- * time to redesign it for 9.1.
+ * (or at least what to call to set) every non-PGC_INTERNAL variable that
+ * could potentially have PGC_S_DYNAMIC_DEFAULT or PGC_S_ENV_VAR source.
*/
if (context == PGC_SIGHUP && applySettings)
{
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 55d41ae7d6..2e21bf0338 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -5939,6 +5939,8 @@ InitializeGUCOptionsFromEnvironment(void)
* rlimit isn't exactly an "environment variable", but it behaves about
* the same. If we can identify the platform stack depth rlimit, increase
* default stack depth setting up to whatever is safe (but at most 2MB).
+ * (But since this isn't really an environment variable, report the
+ * setting as PGC_S_DYNAMIC_DEFAULT not PGC_S_ENV_VAR.)
*/
stack_rlimit = get_stack_depth_rlimit();
if (stack_rlimit > 0)
@@ -5952,7 +5954,7 @@ InitializeGUCOptionsFromEnvironment(void)
new_limit = Min(new_limit, 2048);
sprintf(limbuf, "%ld", new_limit);
SetConfigOption("max_stack_depth", limbuf,
- PGC_POSTMASTER, PGC_S_ENV_VAR);
+ PGC_POSTMASTER, PGC_S_DYNAMIC_DEFAULT);
}
}
}
@@ -7618,6 +7620,8 @@ set_config_option(const char *name, const char *value,
name)));
return 0;
}
+ /* The source should be a boot_val or a dynamic default. */
+ Assert(source <= PGC_S_DYNAMIC_DEFAULT);
break;
case PGC_POSTMASTER:
if (context == PGC_SIGHUP)
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index efcbad7842..385c97fc76 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -83,8 +83,8 @@ typedef enum
* override the postmaster command line.) Tracking the source allows us
* to process sources in any convenient order without affecting results.
* Sources <= PGC_S_OVERRIDE will set the default used by RESET, as well
- * as the current value. Note that source == PGC_S_OVERRIDE should be
- * used when setting a PGC_INTERNAL option.
+ * as the current value. Note that source == PGC_S_DYNAMIC_DEFAULT should
+ * be used when setting a non-compile-time-constant PGC_INTERNAL option.
*
* PGC_S_INTERACTIVE isn't actually a source value, but is the
* dividing line between "interactive" and "non-interactive" sources for
