PLAT-7494: rocksdb stall on manual Flush() and CompactRange() (#57)

Author: matthewvon

db/db_impl/db_impl_compaction_flush.cc

@@ -1989,6 +1989,10 @@ Status DBImpl::FlushMemTable(ColumnFamilyData* cfd,
     }
   }
 
+  if (flush_reason == FlushReason::kManualCompaction ||
+      flush_reason == FlushReason::kManualFlush) {
+    cfd->imm()->BeginManualOperation();
+  }
   autovector<FlushRequest> flush_reqs;
   autovector<uint64_t> memtable_ids_to_wait;
   {
@@ -2107,6 +2111,10 @@ Status DBImpl::FlushMemTable(ColumnFamilyData* cfd,
       tmp_cfd->UnrefAndTryDelete();
     }
   }
+  if (flush_reason == FlushReason::kManualCompaction ||
+      flush_reason == FlushReason::kManualFlush) {
+    cfd->imm()->CompleteManualOperation();
+  }
   TEST_SYNC_POINT("DBImpl::FlushMemTable:FlushMemTableFinished");
   return s;
 }

db/memtable_list.cc

@@ -329,7 +329,8 @@ bool MemTableListVersion::TrimHistory(autovector<MemTable*>* to_delete,
 // not yet started.
 bool MemTableList::IsFlushPending() const {
   if ((flush_requested_ && num_flush_not_started_ > 0) ||
-      (num_flush_not_started_ >= min_write_buffer_number_to_merge_)) {
+      (num_flush_not_started_ >= min_write_buffer_number_to_merge_) ||
+      (active_manuals_ && num_flush_not_started_)) {
     assert(imm_flush_needed.load(std::memory_order_relaxed));
     return true;
   }

db/memtable_list.h

@@ -391,6 +391,13 @@ class MemTableList {
   void RemoveOldMemTables(uint64_t log_number,
                           autovector<MemTable*>* to_delete);
 
+  void BeginManualOperation() { ++active_manuals_; };
+
+  void CompleteManualOperation() {
+    assert(active_manuals_ >= 1);
+    --active_manuals_;
+  };
+
  private:
   friend Status InstallMemtableAtomicFlushResults(
       const autovector<MemTableList*>* imm_lists,
@@ -436,6 +443,9 @@ class MemTableList {
 
   // Cached value of current_->HasHistory().
   std::atomic<bool> current_has_history_;
+
+  // count of manual flush/compactions active
+  std::atomic<int> active_manuals_{0};
 };
 
 // Installs memtable atomic flush results.