On 1/6/15 12:57 AM, Josh Berkus wrote:
> On 01/05/2015 05:43 PM, Peter Eisentraut wrote:
>> The wins on the other hand are obscure: You can now use SHOW to inspect
>> recovery settings. You can design your own configuration file include
>> structures to set them. These are not bad, but is that all?
>
> That's not the only potential win, and it's not small either. I'll be
> able to tell what master a replica is replicating from using via a port
> 5432 connection (currently there is absolutely no way to do this).
That's one particular case of what I mentioned above under using SHOW to
inspect recovery settings. I agree that that's important, but it
doesn't look like there is a consensus that it justifies all the drawbacks.
That said, there is a much simpler way to achieve that specific
functionality: Expose all the recovery settings as fake read-only GUC
variables. See attached patch for an example.
Btw., I'm not sure that everyone will be happy to have primary_conninfo
visible, since it might contain passwords.
> ... and there you hit on one of the other issues with recovery.conf,
> which is that it's a configuration file with configuration parameters
> which gets automatically renamed when a standby is promoted. This plays
> merry hell with configuration management systems. The amount of
> conditional logic I've had to write for Salt to handle recovery.conf
> truly doesn't bear thinking about. There may be some other way to make
> recovery.conf configuration-management friendly, but I haven't thought
> of it.
I have written similar logic, and while it's not pleasant, it's doable.
This issue would really only go away if you don't use a file to signal
recovery at all, which you have argued for, but which is really a
separate and more difficult problem.
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 218de87..477b906 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -237,10 +237,10 @@ static int recovery_min_apply_delay = 0;
static TimestampTz recoveryDelayUntilTime;
/* options taken from recovery.conf for XLOG streaming */
-static bool StandbyModeRequested = false;
-static char *PrimaryConnInfo = NULL;
-static char *PrimarySlotName = NULL;
-static char *TriggerFile = NULL;
+bool StandbyModeRequested = false;
+char *PrimaryConnInfo = NULL;
+char *PrimarySlotName = NULL;
+char *TriggerFile = NULL;
/* are we currently in standby mode? */
bool StandbyMode = false;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index f6df077..6caadff 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -864,6 +864,15 @@ static struct config_bool ConfigureNamesBool[] =
NULL, NULL, NULL
},
{
+ {"standby_mode", PGC_INTERNAL, WAL_SETTINGS,
+ gettext_noop("TODO"),
+ NULL
+ },
+ &StandbyModeRequested,
+ false,
+ NULL, NULL, NULL
+ },
+ {
{"fsync", PGC_SIGHUP, WAL_SETTINGS,
gettext_noop("Forces synchronization of updates to disk."),
gettext_noop("The server will use the fsync() system call in several places to make "
@@ -3275,6 +3284,37 @@ static struct config_string ConfigureNamesString[] =
},
{
+ {"primary_conninfo", PGC_INTERNAL, WAL_SETTINGS,
+ gettext_noop("TODO"),
+ NULL,
+ GUC_SUPERUSER_ONLY
+ },
+ &PrimaryConnInfo,
+ NULL,
+ NULL, NULL, NULL
+ },
+
+ {
+ {"primary_slot_name", PGC_INTERNAL, WAL_SETTINGS,
+ gettext_noop("TODO"),
+ NULL
+ },
+ &PrimarySlotName,
+ NULL,
+ NULL, NULL, NULL
+ },
+
+ {
+ {"trigger_file", PGC_INTERNAL, WAL_SETTINGS,
+ gettext_noop("TODO"),
+ NULL
+ },
+ &TriggerFile,
+ NULL,
+ NULL, NULL, NULL
+ },
+
+ {
{"application_name", PGC_USERSET, LOGGING_WHAT,
gettext_noop("Sets the application name to be reported in statistics and logs."),
NULL,
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 138deaf..eeb9461 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -100,6 +100,11 @@ extern bool fullPageWrites;
extern bool wal_log_hints;
extern bool log_checkpoints;
+extern bool StandbyModeRequested;
+extern char *PrimaryConnInfo;
+extern char *PrimarySlotName;
+extern char *TriggerFile;
+
/* WAL levels */
typedef enum WalLevel
{
--
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