Fix fetch log streamingly bug.

src/logservice/palf/log_sliding_window.cpp

@@ -892,12 +892,17 @@ int LogSlidingWindow::handle_next_submit_log_(bool &is_committed_lsn_updated)
               (void) set_last_submit_log_info_(begin_lsn, log_end_lsn, tmp_log_id, \
                   group_entry_header.get_log_proposal_id());
               if (FOLLOWER == state_mgr_->get_role() || state_mgr_->is_leader_reconfirm()) {
+                bool is_need_fetch = false;
+                const LSN log_committed_end_lsn = group_entry_header.get_committed_end_lsn();
                 try_update_committed_lsn_for_fetch_(log_end_lsn, tmp_log_id, \
-                    group_entry_header.get_committed_end_lsn());
+                    log_committed_end_lsn, is_need_fetch);
+                if (is_need_fetch) {
+                  try_fetch_log_streamingly_(log_committed_end_lsn);
+                }
                 // Advance committed_end_lsn_, follower/reconfirm leader needs
                 // the order with try_update_committed_lsn_for_fetch_() is important,
                 // this exec order can avoid trigger failure of next round fetch by sliding_cb()
-                (void) try_advance_committed_lsn_(group_entry_header.get_committed_end_lsn());
+                (void) try_advance_committed_lsn_(log_committed_end_lsn);
                 is_committed_lsn_updated = true;
               }
             }
@@ -1537,9 +1542,11 @@ void LogSlidingWindow::try_reset_last_fetch_log_info_(const LSN &expected_end_ls
   }
 }
 
-void LogSlidingWindow::try_update_committed_lsn_for_fetch_(const LSN &log_end_lsn,
+void LogSlidingWindow::try_update_committed_lsn_for_fetch_(
+    const LSN &log_end_lsn,
     const int64_t &log_id,
-    const LSN &log_committed_end_lsn)
+    const LSN &log_committed_end_lsn,
+    bool &is_need_fetch)
 {
   bool need_update = false;
   LSN last_fetch_end_lsn;
@@ -1570,9 +1577,22 @@ void LogSlidingWindow::try_update_committed_lsn_for_fetch_(const LSN &log_end_ls
                || log_id == last_fetch_max_log_id_) {
       LSN committed_end_lsn;
       get_committed_end_lsn_(committed_end_lsn);
+      // The order is fatal:
+      // 1) update last_fetch_committed_end_lsn_
+      // 2) check last slide end_lsn to decide fetching log streamingly or not.
       ATOMIC_STORE(&last_fetch_committed_end_lsn_.val_, log_committed_end_lsn.val_);
+      MEM_BARRIER();
+      // The committed_end_lsn may already be updated at least to this value by previous group log.
+      // And the logs before log_committed_end_lsn have been slid out.
+      // For this scenario, it need triger fetch log streamingly now.
+      LSN last_slide_end_lsn;
+      get_last_slide_end_lsn_(last_slide_end_lsn);
+      if (committed_end_lsn >= log_committed_end_lsn
+          && last_slide_end_lsn >= log_committed_end_lsn) {
+        is_need_fetch = true;
+      }
       PALF_LOG(INFO, "update last fetch log info", K_(palf_id), K_(self), K(last_fetch_end_lsn), K(log_id),
-          K_(last_fetch_end_lsn), K_(last_fetch_committed_end_lsn), K(committed_end_lsn));
+          K_(last_fetch_end_lsn), K_(last_fetch_committed_end_lsn), K(committed_end_lsn), K(last_slide_end_lsn));
     } else {
       PALF_LOG(INFO, "last_fetch_max_log_id_ has changed, skip update", K_(palf_id), K_(self),
           K(last_fetch_end_lsn), K(log_id), K_(last_fetch_max_log_id), K_(last_fetch_end_lsn),
@@ -1704,15 +1724,23 @@ int LogSlidingWindow::do_fetch_log_(const FetchTriggerType &trigger_type,
     // so just set it to PALF_SLIDING_WINDOW_SIZE
     const int64_t fetch_log_count = PALF_SLIDING_WINDOW_SIZE - skip_log_count;
     // Update last_fetch_end_lsn_ AND last_fetch_max_log_id_
+    bool need_exec_fetch = true;
     do {
       ObSpinLockGuard guard(fetch_info_lock_);
       const LSN tmp_end_lsn = fetch_start_lsn + fetch_log_size;
+      if (FetchTriggerType::SLIDING_CB == trigger_type
+          && !last_fetch_committed_end_lsn_.is_valid()) {
+        // Streamingly fetching may trigger more than one time,
+        // we need filter duplicated ops here.
+        need_exec_fetch = false;
+      } else {
         ATOMIC_STORE(&last_fetch_end_lsn_.val_, tmp_end_lsn.val_);
         last_fetch_max_log_id_ = fetch_start_log_id + fetch_log_count - 1;
         last_fetch_committed_end_lsn_.reset();
+      }
     } while(0);
 
-    if (OB_SUCC(ret)) {
+    if (OB_SUCC(ret) && need_exec_fetch) {
       FetchLogType fetch_type = FETCH_LOG_FOLLOWER;
       if (LEADER_RECONFIRM == trigger_type) {
         fetch_type = FETCH_LOG_LEADER_RECONFIRM;
@@ -1863,6 +1891,8 @@ int LogSlidingWindow::sliding_cb(const int64_t sn, const FixedSlidingWindowSlot
             log_proposal_id, log_accum_checksum);
       }
 
+      MEM_BARRIER();  // ensure last_slide_log_info_ has been updated before fetch log streamingly
+
       if (OB_SUCC(ret)
           && (FOLLOWER == state_mgr_->get_role() || state_mgr_->is_leader_reconfirm())) {
         // Check if need fetch log streamingly,

src/logservice/palf/log_sliding_window.h

@@ -304,7 +304,8 @@ private:
   void try_reset_last_fetch_log_info_(const LSN &expected_end_lsn, const int64_t log_id);
   void try_update_committed_lsn_for_fetch_(const LSN &expected_end_lsn,
       const int64_t &expected_log_id,
-      const LSN &log_committed_end_lsn);
+      const LSN &log_committed_end_lsn,
+      bool &is_need_fetch);
   void try_fetch_log_streamingly_(const LSN &log_end_lsn);
   int do_fetch_log_(const FetchTriggerType &trigger_type,
                     const common::ObAddr &dest,