From 120e056a9469dcf5ac449bb8fcb3547bc4f06d12 Mon Sep 17 00:00:00 2001
From: xue_meng_en <1836611252@qq.com>
Date: Fri, 5 Feb 2021 10:55:52 +0800
Subject: [PATCH] =?UTF-8?q?=E6=94=AF=E6=8C=81=E5=9C=A8=E7=BA=BF=E6=89=A9?=
 =?UTF-8?q?=E5=AE=B9=E5=86=85=E6=A0=B8=E9=80=82=E9=85=8D=E4=BF=AE=E6=94=B9?=
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---
 src/bin/gs_guc/pg_guc.cpp                     | 65 +++++++++++++++++++
 src/common/backend/utils/misc/guc.cpp         | 22 +++++++
 .../process/postmaster/postmaster.cpp         |  7 ++
 3 files changed, 94 insertions(+)

diff --git a/src/bin/gs_guc/pg_guc.cpp b/src/bin/gs_guc/pg_guc.cpp
index ac9b08647..8b26280b2 100644
--- a/src/bin/gs_guc/pg_guc.cpp
+++ b/src/bin/gs_guc/pg_guc.cpp
@@ -1023,6 +1023,64 @@ append_string_info(char **optLines, const char *newContext)
     return optLinesResult;
 }
 
+static bool IsLastNotNullReplconninfo(char** optLines, char* replconninfoX)
+{
+    int notNullReplconninfoNums = 0;
+    bool isReplconninfoXNull = true;
+    bool matchReplconninfoX = false;
+    char* p = NULL;
+
+    for (int i = 0; optLines != NULL && optLines[i] != NULL; i++) {
+        p = optLines[i];
+        /* Skip all the blanks at the begin of the optLine */
+        while (p != NULL && isspace((unsigned char)*p)) {
+            ++p;
+        }
+        if (p == NULL) {
+            continue;
+        }
+        if (*p == '#') {
+            ++p;
+            while (p != NULL && isspace((unsigned char)*p)) {
+                ++p;
+            }
+            if (p != NULL && strncmp(p, replconninfoX, strlen(replconninfoX)) == 0) {
+                return false;
+            }
+            continue;
+        }
+        if (p != NULL && strncmp(p, "replconninfo", strlen("replconninfo")) == 0) {
+            if (strncmp(p, replconninfoX, strlen(replconninfoX)) == 0) {
+                matchReplconninfoX = true;
+            }
+            p += strlen(replconninfoX);
+            /* Skip all the blanks between the param and '=' */
+            while (p != NULL && isspace((unsigned char)*p)) {
+                p++;
+            }
+            /* Skip '=' */
+            if (p != NULL && *p == '=') {
+                p++;
+            }
+            /* Skip all the blanks between the '=' and value */
+            while (p != NULL && isspace((unsigned char)*p)) {
+                p++;
+            }
+            if (p != NULL && strncmp(p, "''", strlen("''")) != 0 &&
+                strncmp(p, "''", strlen("\"\"")) != 0) {
+                ++notNullReplconninfoNums;
+                if (matchReplconninfoX) {
+                    isReplconninfoXNull = false;
+                }
+            }
+        }
+    }
+    if (notNullReplconninfoNums == 1 && !isReplconninfoXNull) {
+        return true;
+    }
+    return false;
+}
+
 /*
  * @@GaussDB@@
  * Brief            :
@@ -1114,6 +1172,13 @@ do_gucset(const char *action_type, const char *data_dir)
             }
         }
 
+        if (strncmp(config_param[i], "replconninfo", strlen("replconninfo")) == 0 &&
+            config_value[i] != NULL && strncmp(config_value[i], "''", strlen("''") &&
+            IsLastNotNullReplconninfo(opt_lines, config_param[i])) {
+            write_stderr("\nWARNING: This is the last valid replConnInfo, once set to null, "
+                "the host role will be changed to Normal if the local_role is primary now.\n");
+        }
+
         /* find the line where guc parameter in */
         lines_index = find_gucoption(opt_lines, config_param[i], NULL, NULL, &optvalue_off, &optvalue_len);
         /* get the type of gs_guc execution */
diff --git a/src/common/backend/utils/misc/guc.cpp b/src/common/backend/utils/misc/guc.cpp
index 29c677e7b..0cf98f2c2 100644
--- a/src/common/backend/utils/misc/guc.cpp
+++ b/src/common/backend/utils/misc/guc.cpp
@@ -17654,6 +17654,22 @@ static bool check_replconninfo(char** newval, void** extra, GucSource source)
     return true;
 }
 
+/*
+ * @@GaussDB@@
+ * Brief			: Determine if all eight replconninfos are empty.
+ * Description		:
+ * Notes			:
+ */
+static inline bool GetReplCurArrayIsNull()
+{
+    for (int i = 1; i < MAX_REPLNODE_NUM; i++) {
+        if (t_thrd.postmaster_cxt.ReplConnArray[i] != NULL) {
+            return false;
+        }
+    }
+    return true;
+}
+
 /*
  * @@GaussDB@@
  * Brief			: Parse replconninfo1.
@@ -17675,6 +17691,12 @@ static void assign_replconninfo1(const char* newval, void* extra)
     if (u_sess->attr.attr_storage.ReplConnInfoArr[1] != NULL && newval != NULL &&
         strcmp(u_sess->attr.attr_storage.ReplConnInfoArr[1], newval) != 0) {
         t_thrd.postmaster_cxt.ReplConnChanged[1] = true;
+        // perceive single --> primary_standby
+        if (t_thrd.postmaster_cxt.HaShmData != NULL &&
+            t_thrd.postmaster_cxt.HaShmData->current_mode == NORMAL_MODE &&
+            !GetReplCurArrayIsNull()) {
+                t_thrd.postmaster_cxt.HaShmData->current_mode = PRIMARY_MODE;
+        }
     }
 }
 
diff --git a/src/gausskernel/process/postmaster/postmaster.cpp b/src/gausskernel/process/postmaster/postmaster.cpp
index cb1224ace..d25ae836e 100755
--- a/src/gausskernel/process/postmaster/postmaster.cpp
+++ b/src/gausskernel/process/postmaster/postmaster.cpp
@@ -9496,6 +9496,13 @@ static void check_and_reset_ha_listen_port(void)
             signal_child(g_instance.pid_cxt.RemoteServicePID, SIGTERM);
 
         ListenSocketRegulation();
+
+        if (t_thrd.postmaster_cxt.HaShmData != NULL &&
+            t_thrd.postmaster_cxt.HaShmData->repl_list_num == 0 && 
+            t_thrd.postmaster_cxt.HaShmData->current_mode == PRIMARY_MODE) {
+            t_thrd.postmaster_cxt.HaShmData->current_mode = NORMAL_MODE;
+            SetServerMode(NORMAL_MODE);
+        }
     }
 
     return;