!4171 【bugfix】修复主节点按需回放时，重启备节点，主节点卡在PM_WAIT_BACKEND

Merge pull request !4171 from 周聪/bugfix_cannot_create_process

src/gausskernel/process/postmaster/postmaster.cpp

@@ -486,6 +486,7 @@ static bool CheckSignalByFile(const char *filename, void *infoPtr, size_t infoSi
 
 int GaussDbThreadMain(knl_thread_arg* arg);
 const char* GetThreadName(knl_thread_role role);
+void SSOndemandProcExitIfStayWaitBackends();
 
 #ifdef EXEC_BACKEND
 
@@ -3976,6 +3977,10 @@ static int ServerLoop(void)
                             result = BackendStartup(port, isConnectHaPort);
                         }
 
+                        if (SS_CLUSTER_ONDEMAND_RECOVERY && SS_IN_REFORM &&
+                            result != STATUS_OK && pmState == PM_WAIT_BACKENDS) {
+                            SSOndemandProcExitIfStayWaitBackends();
+                        }
                         if (result != STATUS_OK) {
                             if (port->is_logic_conn) {
                                 gs_close_gsocket(&port->gs_sock);
@@ -15086,3 +15091,20 @@ void SSRestartFailoverPromote()
     pmState = PM_WAIT_BACKENDS;
     SShandle_promote_signal();
 }
+
+void SSOndemandProcExitIfStayWaitBackends() 
+{
+    int failTimes = 0;
+    while (failTimes < WAIT_PMSTATE_UPDATE_TRIES && pmState == PM_WAIT_BACKENDS) {
+        PostmasterStateMachine();
+        pg_usleep(REFORM_WAIT_LONG);
+        failTimes++;
+    }
+    if (pmState == PM_WAIT_BACKENDS) {
+        ereport(WARNING, (errmsg("Proc exit because pmState stay %s for %d times, "
+            "when reform failed and in ondemand recovery, "
+            "to avoid pmState being stuck in PM_WAIT_BACKENDS.", 
+            GetPMState(pmState), WAIT_PMSTATE_UPDATE_TRIES)));
+        proc_exit(1);
+    }
+}

src/gausskernel/storage/buffer/bufmgr.cpp

@@ -1714,11 +1714,10 @@ Buffer buffer_read_extended_internal(Relation reln, ForkNumber fork_num, BlockNu
 Buffer ReadBufferExtended(Relation reln, ForkNumber fork_num, BlockNumber block_num, ReadBufferMode mode,
                           BufferAccessStrategy strategy)
 {
-    if (IsDefaultExtremeRtoMode() &&
-        (!RecoveryInProgress() || !IsExtremeRtoRunning() || !is_exrto_standby_read_worker())) {
-        return buffer_read_extended_internal(reln, fork_num, block_num, mode, strategy);
-    } else {
+    if (IsDefaultExtremeRtoMode() && RecoveryInProgress() && IsExtremeRtoRunning() && is_exrto_standby_read_worker()) {
         return standby_read_buf(reln, fork_num, block_num, mode, strategy);
+    } else {
+        return buffer_read_extended_internal(reln, fork_num, block_num, mode, strategy);
     }
 }
 

src/include/access/multi_redo_api.h

@@ -68,7 +68,7 @@ static const uint32 BIG_RECORD_LENGTH = XLOG_BLCKSZ * 16;
 
 #define IS_EXRTO_READ (IsExtremeRedo() && g_instance.attr.attr_storage.EnableHotStandby && IsDefaultExtremeRtoMode())
 #define IS_EXRTO_STANDBY_READ (IS_EXRTO_READ && pm_state_is_hot_standby())
-#define IS_EXRTO_RECOVERY_IN_PROGRESS (RecoveryInProgress() && IsExtremeRedo())
+#define IS_EXRTO_RECOVERY_IN_PROGRESS (RecoveryInProgress() && IsExtremeRedo() && IsDefaultExtremeRtoMode())
 
 inline bool is_exrto_standby_read_worker()
 {

src/include/ddes/dms/ss_reform_common.h

@@ -31,6 +31,8 @@
 #define REFORM_WAIT_LONG 100000 /* 0.1 sec */
 #define WAIT_REFORM_CTRL_REFRESH_TRIES 1000
 
+#define WAIT_PMSTATE_UPDATE_TRIES 100
+
 #define REFORM_CTRL_VERSION 1
 
 typedef struct SSBroadcastCancelTrx {