!1536 notify 支持指定为cascade standby

Merge pull request !1536 from 刘春/2.0.0

src/bin/pg_ctl/pg_ctl.cpp

@@ -171,6 +171,7 @@ static char switchover_file[MAXPGPATH];
 static char promote_file[MAXPGPATH];
 static char primary_file[MAXPGPATH];
 static char standby_file[MAXPGPATH];
+static char cascade_standby_file[MAXPGPATH];
 static char pg_ctl_lockfile[MAXPGPATH];
 static char pg_conf_file[MAXPGPATH];
 static FILE* lockfile = NULL;
@@ -2147,6 +2148,10 @@ static void do_notify(uint32 term)
                pgha_str[strlen("primary")] == '\0') {
         notify_file = xstrdup(primary_file);
         notify_mode = PRIMARY_MODE;
+    } else if ((pgha_str != NULL) && 0 == strncmp(pgha_str, "cascade_standby", strlen("cascade_standby")) &&
+               pgha_str[strlen("cascade_standby")] == '\0') {
+        notify_file = xstrdup(cascade_standby_file);
+        notify_mode = CASCADE_STANDBY_MODE;
     } else {
         pg_log(PG_WARNING, _(" the parameter of notify is not recognized\n"));
         exit(1);
@@ -3786,6 +3791,8 @@ static char* get_localrole_string(ServerMode mode)
             return "Primary";
         case STANDBY_MODE:
             return "Standby";
+        case CASCADE_STANDBY_MODE:
+            return "Cascade Standby";
         case PENDING_MODE:
             return "Pending";
         default:
@@ -5099,6 +5106,8 @@ int main(int argc, char** argv)
         securec_check_ss_c(ret, "\0", "\0");
         ret = snprintf_s(standby_file, MAXPGPATH, MAXPGPATH - 1, "%s/standby", pg_data);
         securec_check_ss_c(ret, "\0", "\0");
+        ret = snprintf_s(cascade_standby_file, MAXPGPATH, MAXPGPATH - 1, "%s/cascade_standby", pg_data);
+        securec_check_ss_c(ret, "\0", "\0");
         ret = snprintf_s(pg_ctl_lockfile, MAXPGPATH, MAXPGPATH - 1, "%s/pg_ctl.lock", pg_data);
         securec_check_ss_c(ret, "\0", "\0");
         ret = snprintf_s(pg_conf_file, MAXPGPATH, MAXPGPATH - 1, "%s/postgresql.conf", pg_data);

src/gausskernel/process/postmaster/postmaster.cpp

@@ -1,4 +1,4 @@
-/* -------------------------------------------------------------------------
+/* -------------------------------------------------------------------------
  *
  * postmaster.cpp
  *	  This program acts as a clearing house for requests to the
@@ -4923,6 +4923,7 @@ static void reaper(SIGNAL_ARGS)
             if (g_instance.demotion > NoDemote &&
                 t_thrd.postmaster_cxt.HaShmData->current_mode == STANDBY_MODE &&
                 (EXIT_STATUS_0(exitstatus) || EXIT_STATUS_1(exitstatus))) {
+                pmState = PM_WAIT_BACKENDS;
                 continue;
             }
 
@@ -7197,6 +7198,27 @@ static void handle_standby_signal(volatile HaShmemData* hashmdata)
     }
 }
 
+static void handle_cascade_standby_signal(volatile HaShmemData* hashmdata)
+{
+    if (g_instance.pid_cxt.StartupPID != 0 &&
+        (pmState == PM_STARTUP ||
+         pmState == PM_RECOVERY ||
+         pmState == PM_HOT_STANDBY ||
+         pmState == PM_WAIT_READONLY)) {
+        hashmdata->current_mode = STANDBY_MODE;
+        hashmdata->is_cascade_standby = true;
+        PMUpdateDBState(NEEDREPAIR_STATE, get_cur_mode(), get_cur_repl_num());
+        ereport(LOG,
+           (errmsg("update gaussdb state file: db state(NEEDREPAIR_STATE), server mode(%s)",
+               wal_get_role_string(get_cur_mode()))));
+        /*
+        * wakeup startup process from sleep by signal, cause we are
+        * in standby mode, the signal has no specific affect.
+        */
+        SendNotifySignal(NOTIFY_CASCADE_STANDBY, g_instance.pid_cxt.StartupPID);
+        UpdateOptsFile();
+    }
+}
 /*
  * sigusr1_handler - handle signal conditions from child processes
  */
@@ -7375,6 +7397,11 @@ static void sigusr1_handler(SIGNAL_ARGS)
         handle_standby_signal(hashmdata);
     }
 
+    /* If it is cascade standby signal, then set HaShmData and send sigusr2 to startup process */
+    if (CheckCascadeStandbySignal()) {
+        handle_cascade_standby_signal(hashmdata);
+    }
+
     if (CheckPostmasterSignal(PMSIGNAL_UPDATE_NORMAL)) {
         PMUpdateDBState(NORMAL_STATE, get_cur_mode(), get_cur_repl_num());
         ereport(LOG,

src/gausskernel/process/postmaster/startup.cpp

@@ -109,6 +109,8 @@ static void StartupProcSigusr2Handler(SIGNAL_ARGS)
         t_thrd.startup_cxt.primary_triggered = true;
     } else if (CheckNotifySignal(NOTIFY_STANDBY)) {
         t_thrd.startup_cxt.standby_triggered = true;
+    } else if (CheckNotifySignal(NOTIFY_CASCADE_STANDBY)) {
+        t_thrd.startup_cxt.standby_triggered = true;
     } else if (CheckNotifySignal(NOTIFY_FAILOVER)) {
         t_thrd.startup_cxt.failover_triggered = true;
         WakeupRecovery();

src/gausskernel/storage/access/transam/xlog.cpp

@@ -144,6 +144,7 @@
 #define SWITCHOVER_SIGNAL_FILE "switchover"
 #define PRIMARY_SIGNAL_FILE "primary"
 #define STANDBY_SIGNAL_FILE "standby"
+#define CASCADE_STANDBY_SIGNAL_FILE "cascade_standby"
 #define XLOG_SWITCH_HISTORY_FILE "switch.history"
 #define MAX_PATH_LEN 1024
 #define MAX(A, B) ((B) > (A) ? (B) : (A))
@@ -16755,6 +16756,24 @@ bool CheckStandbySignal(void)
     return false;
 }
 
+/*
+ * Check whether the signal is cascade standby signal
+ */
+bool CheckCascadeStandbySignal(void)
+{
+    struct stat stat_buf;
+
+    if (stat(CASCADE_STANDBY_SIGNAL_FILE, &stat_buf) == 0) {
+        /*
+         * Since we are in a signal handler, it's not safe to elog. We
+         * silently ignore any error from unlink.
+         */
+        (void)unlink(CASCADE_STANDBY_SIGNAL_FILE);
+        return true;
+    }
+    return false;
+}
+
 /*
  * Check to see if a switchover request has arrived and
  * read demote mode from switchover signal file.

src/include/access/xlog.h

@@ -389,6 +389,7 @@ extern bool CheckFinishRedoSignal(void);
 extern bool CheckPromoteSignal(void);
 extern bool CheckPrimarySignal(void);
 extern bool CheckStandbySignal(void);
+extern bool CheckCascadeStandbySignal(void);
 extern bool CheckNormalSignal(void);
 extern int CheckSwitchoverSignal(void);
 

src/include/postmaster/startup.h

@@ -12,8 +12,8 @@
 #ifndef _STARTUP_H
 #define _STARTUP_H
 
-typedef enum { NOTIFY_PRIMARY = 0, NOTIFY_STANDBY, NOTIFY_FAILOVER, NOTIFY_SWITCHOVER, NUM_NOTIFYS } NotifyReason;
-
+typedef enum { NOTIFY_PRIMARY = 0, NOTIFY_STANDBY, NOTIFY_CASCADE_STANDBY, NOTIFY_FAILOVER,
+               NOTIFY_SWITCHOVER, NUM_NOTIFYS } NotifyReason;
 /*
  * Save the notify signal reason in the share memory.
  * NotifySignalFlags include primary signal, standby signal and promote signal.