Re: Nicer error when connecting to standby with hot_standby=off

[Fujii Masao]

On 2021/03/24 16:59, Alvaro Herrera wrote:

On 2021-Mar-24, Fujii Masao wrote:

On 2021/03/24 5:59, Tom Lane wrote:

Alvaro Herrera <alvhe...@alvh.no-ip.org> writes:

FATAL:  the database system is starting up
DETAIL:  WAL is being applied to recover from a system crash.
or
DETAIL:  The system is applying WAL to recover from a system crash.
or
DETAIL:  The startup process is applying WAL to recover from a system crash.

I don't think the postmaster has enough context to know if that's
actually true.  It just launches the startup process and waits for
results.  If somebody saw this during a normal (non-crash) startup,
they'd be justifiably alarmed.

Yes, so logging "the database system is starting up" seems enough to me.

No objection.

Thanks! So I changed the message reported at PM_STARTUP to that one,
based on v8 patch that James posted upthread. I also ran pgindent for
the patch. Attached is the updated version of the patch.

Barring any objection, I will commit this.

Regards,

--
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION

diff --git a/src/backend/postmaster/postmaster.c 
b/src/backend/postmaster/postmaster.c
index ef0be4ca38..4a3ca78c1b 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -2294,6 +2294,18 @@ retry1:
                                        (errcode(ERRCODE_CANNOT_CONNECT_NOW),
                                         errmsg("the database system is 
starting up")));
                        break;
+               case CAC_NOTCONSISTENT:
+                       if (EnableHotStandby)
+                               ereport(FATAL,
+                                               
(errcode(ERRCODE_CANNOT_CONNECT_NOW),
+                                                errmsg("the database system is 
not yet accepting connections"),
+                                                errdetail("Consistent recovery 
state has not been yet reached.")));
+                       else
+                               ereport(FATAL,
+                                               
(errcode(ERRCODE_CANNOT_CONNECT_NOW),
+                                                errmsg("the database system is 
not accepting connections"),
+                                                errdetail("Hot standby mode is 
disabled.")));
+                       break;
                case CAC_SHUTDOWN:
                        ereport(FATAL,
                                        (errcode(ERRCODE_CANNOT_CONNECT_NOW),
@@ -2435,10 +2447,11 @@ canAcceptConnections(int backend_type)
        {
                if (Shutdown > NoShutdown)
                        return CAC_SHUTDOWN;    /* shutdown is pending */
-               else if (!FatalError &&
-                                (pmState == PM_STARTUP ||
-                                 pmState == PM_RECOVERY))
+               else if (!FatalError && pmState == PM_STARTUP)
                        return CAC_STARTUP; /* normal startup */
+               else if (!FatalError && pmState == PM_RECOVERY)
+                       return CAC_NOTCONSISTENT;       /* not yet at 
consistent recovery
+                                                                               
 * state */
                else
                        return CAC_RECOVERY;    /* else must be crash recovery 
*/
        }
diff --git a/src/include/libpq/libpq-be.h b/src/include/libpq/libpq-be.h
index 30fb4e613d..891394b0c3 100644
--- a/src/include/libpq/libpq-be.h
+++ b/src/include/libpq/libpq-be.h
@@ -70,7 +70,12 @@ typedef struct
 
 typedef enum CAC_state
 {
-       CAC_OK, CAC_STARTUP, CAC_SHUTDOWN, CAC_RECOVERY, CAC_TOOMANY,
+       CAC_OK,
+       CAC_STARTUP,
+       CAC_SHUTDOWN,
+       CAC_RECOVERY,
+       CAC_NOTCONSISTENT,
+       CAC_TOOMANY,
        CAC_SUPERUSER
 } CAC_state;