[Fetch Data] Linearized buffer memory managment

This commit removes freeLinearizedBuf() to avoid chunks that have
references to deleted buffers. They will now be marked as deleted when
unpinned. All buffers should now be removed via BufferManagers::free.

Signed-off-by: Dmitrii Makarenko <dmitrii.makarenko@intel.com>

Author: Devjiu

omniscidb/DataMgr/BufferMgr/Buffer.cpp

@@ -166,4 +166,24 @@ int8_t* Buffer::getMemoryPtr() {
 void Buffer::setMemoryPtr(int8_t* new_ptr) {
   mem_ = new_ptr;
 }
+
+int Buffer::unPin() {
+  std::unique_lock<std::mutex> pin_lock(pin_mutex_);
+  int res = (--pin_count_);
+  if (!res && delete_on_unpin_) {
+    pin_lock.unlock();
+    bm_->free(this);
+  }
+  return res;
+}
+
+void Buffer::deleteWhenUnpinned() {
+  std::unique_lock<std::mutex> pin_lock(pin_mutex_);
+  if (pin_count_) {
+    delete_on_unpin_ = true;
+  } else {
+    pin_lock.unlock();
+    bm_->free(this);
+  }
+}
 }  // namespace Buffer_Namespace

omniscidb/DataMgr/BufferMgr/Buffer.h

@@ -134,28 +134,14 @@ class Buffer : public AbstractBuffer {
     return (++pin_count_);
   }
 
-  inline int unPin() override {
-    std::lock_guard<std::mutex> pin_lock(pin_mutex_);
-    int res = (--pin_count_);
-    if (!res && delete_on_unpin_) {
-      delete this;
-    }
-    return res;
-  }
+  int unPin() override;
+
   inline int getPinCount() override {
     std::lock_guard<std::mutex> pin_lock(pin_mutex_);
     return (pin_count_);
   }
 
-  inline void deleteWhenUnpinned() override {
-    std::unique_lock<std::mutex> pin_lock(pin_mutex_);
-    if (pin_count_) {
-      delete_on_unpin_ = true;
-    } else {
-      pin_lock.unlock();
-      delete this;
-    }
-  }
+  void deleteWhenUnpinned() override;
 
   // Added for testing.
   int32_t getSlabNum() const { return seg_it_->slab_num; }

omniscidb/DataMgr/BufferMgr/BufferMgr.cpp

@@ -103,6 +103,12 @@ void BufferMgr::clear() {
   // for removal to have them deleted when unpinned.
   for (auto& buf : chunk_index_) {
     if (buf.second->buffer) {
+      // WARN !!!!!!!!!!!!!!!!!!
+      // deleteWhenUnpinned(...) will call free(...) that will call deleteBuffer(...) in
+      // case when segment iterator is valid. That method will try to acquire
+      // chunk_index_mutex_ that already acquired here. To avoid deadlock and remove all
+      // the stuff, we are cleaning segments later we are removing segment iterator.
+      buf.second->buffer->seg_it_ = BufferList::iterator();
       buf.second->buffer->deleteWhenUnpinned();
       buf.second->buffer = nullptr;
     }
@@ -623,6 +629,7 @@ void BufferMgr::deleteBuffer(const ChunkKey& key, const bool) {
   chunk_index_lock.unlock();
   std::lock_guard<std::mutex> sized_segs_lock(sized_segs_mutex_);
   if (seg_it->buffer) {
+    CHECK_EQ(seg_it->buffer->getPinCount(), 0);
     delete seg_it->buffer;  // Delete Buffer for segment
     seg_it->buffer = 0;
   }
@@ -826,11 +833,20 @@ AbstractBuffer* BufferMgr::alloc(const size_t num_bytes) {
   return createBuffer(chunk_key, page_size_, num_bytes);
 }
 
+// all buffer deletions should be done via free(...)
 void BufferMgr::free(AbstractBuffer* buffer) {
   Buffer* casted_buffer = dynamic_cast<Buffer*>(buffer);
   if (casted_buffer == 0) {
     LOG(FATAL) << "Wrong buffer type - expects base class pointer to Buffer type.";
   }
+  // ZeroCopy buffers don't have correct iterators by design.
+  // To delete it we are detecting them and delete explicitly without removing segment as
+  // it done in deleteBuffer(...)
+  if (casted_buffer->seg_it_ == BufferList::iterator()) {
+    delete buffer;
+    return;
+  }
+
   deleteBuffer(casted_buffer->seg_it_->chunk_key);
 }
 

omniscidb/DataMgr/Chunk/Chunk.h

@@ -51,7 +51,14 @@ class Chunk {
       : buffer_(nullptr), index_buf_(nullptr), column_info_(col_info) {}
 
   Chunk(AbstractBuffer* b, AbstractBuffer* ib, ColumnInfoPtr col_info)
-      : buffer_(b), index_buf_(ib), column_info_(col_info) {}
+      : buffer_(b), index_buf_(ib), column_info_(col_info) {
+    if (buffer_) {
+      buffer_->pin();
+    }
+    if (index_buf_) {
+      index_buf_->pin();
+    }
+  }
 
   ~Chunk() { unpinBuffer(); }
 

omniscidb/QueryEngine/ColumnFetcher.cpp

@@ -469,6 +469,10 @@ const int8_t* ColumnFetcher::linearizeColumnFragments(
     }
   }
   CHECK(res.first);  // check merged data buffer
+  // This buffers are associated with Chunk, that created by hands, not with
+  // Chunk::getChunk(...) method So it should be removed to do it we mark both buffers to
+  // delete on unpin in ColumnFetcher dtor. Pin means that none of chunks are uses this
+  // buffer.
   if (!type->isFixedLenArray()) {
     CHECK(res.second);  // check merged index buffer
   }
@@ -1009,34 +1013,3 @@ ChunkIter ColumnFetcher::prepareChunkIter(AbstractBuffer* merged_data_buf,
   merged_chunk_iter.elem_type_size = chunk_iter.elem_type_size;
   return merged_chunk_iter;
 }
-
-void ColumnFetcher::freeLinearizedBuf() {
-  std::lock_guard<std::mutex> linearized_col_cache_guard(linearized_col_cache_mutex_);
-  auto buffer_provider = executor_->getBufferProvider();
-
-  if (!linearized_data_buf_cache_.empty()) {
-    for (auto& kv : linearized_data_buf_cache_) {
-      for (auto& kv2 : kv.second) {
-        buffer_provider->free(kv2.second);
-      }
-    }
-  }
-
-  if (!linearized_idx_buf_cache_.empty()) {
-    for (auto& kv : linearized_idx_buf_cache_) {
-      for (auto& kv2 : kv.second) {
-        buffer_provider->free(kv2.second);
-      }
-    }
-  }
-}
-
-void ColumnFetcher::freeTemporaryCpuLinearizedIdxBuf() {
-  std::lock_guard<std::mutex> linearized_col_cache_guard(linearized_col_cache_mutex_);
-  auto buffer_provider = executor_->getBufferProvider();
-  if (!linearlized_temporary_cpu_index_buf_cache_.empty()) {
-    for (auto& kv : linearlized_temporary_cpu_index_buf_cache_) {
-      buffer_provider->free(kv.second);
-    }
-  }
-}

omniscidb/QueryEngine/ColumnFetcher.h

@@ -37,6 +37,32 @@ class ColumnFetcher {
   ColumnFetcher(Executor* executor,
                 DataProvider* data_provider,
                 const ColumnCacheMap& column_cache);
+  ~ColumnFetcher() {
+    if (!linearized_data_buf_cache_.empty()) {
+      for (auto& kv : linearized_data_buf_cache_) {
+        for (auto& kv2 : kv.second) {
+          kv2.second->deleteWhenUnpinned();
+          kv2.second->unPin();
+        }
+      }
+    }
+
+    if (!linearized_idx_buf_cache_.empty()) {
+      for (auto& kv : linearized_idx_buf_cache_) {
+        for (auto& kv2 : kv.second) {
+          kv2.second->deleteWhenUnpinned();
+          kv2.second->unPin();
+        }
+      }
+    }
+
+    if (!linearlized_temporary_cpu_index_buf_cache_.empty()) {
+      for (auto& kv : linearlized_temporary_cpu_index_buf_cache_) {
+        kv.second->deleteWhenUnpinned();
+        kv.second->unPin();
+      }
+    }
+  };
 
   //! Gets one chunk's pointer and element count on either CPU or GPU.
   static std::pair<const int8_t*, size_t> getOneColumnFragment(
@@ -93,9 +119,6 @@ class ColumnFetcher {
       DeviceAllocator* device_allocator,
       const size_t thread_idx) const;
 
-  void freeTemporaryCpuLinearizedIdxBuf();
-  void freeLinearizedBuf();
-
   DataProvider* getDataProvider() const { return data_provider_; }
 
  private:

omniscidb/QueryEngine/Execute.cpp

@@ -2186,10 +2186,6 @@ hdk::ResultSetTable Executor::executeWorkUnitImpl(
   do {
     SharedKernelContext shared_context(query_infos);
     ColumnFetcher column_fetcher(this, data_provider, column_cache);
-    ScopeGuard scope_guard = [&column_fetcher] {
-      column_fetcher.freeLinearizedBuf();
-      column_fetcher.freeTemporaryCpuLinearizedIdxBuf();
-    };
 
     if (ra_exe_unit.isShuffle()) {
       allocateShuffleBuffers(query_infos, ra_exe_unit, row_set_mem_owner, shared_context);

omniscidb/Tests/JoinHashTableTest.cpp

@@ -670,6 +670,85 @@ TEST(Other, Regression) {
   dropTable("table_b");
 }
 
+TEST(Other, FixedLenArr) {
+  createTable("table_a",
+              {{"si", ctx().int16()}, {"FixedLen", ctx().arrayFixed(2, ctx().int64())}},
+              {2});
+
+  std::ostringstream oss;
+  oss << "{\"si\": 1, \"FixedLen\": [" << 7 << ", " << 233 << "]}" << std::endl;
+  oss << "{\"si\": 1, \"FixedLen\": [" << 5 << ", " << 47 << "]}" << std::endl;
+  oss << "{\"si\": 2, \"FixedLen\": [" << 6 << ", " << 48 << "]}" << std::endl;
+  oss << "{\"si\": 3, \"FixedLen\": [" << 7 << ", " << 49 << "]}" << std::endl;
+  oss << "{\"si\": 4, \"FixedLen\": [" << 8 << ", " << 67 << "]}" << std::endl;
+  oss << "{\"si\": 5, \"FixedLen\": [" << 9 << ", " << 68 << "]}" << std::endl;
+  oss << "{\"si\": 6, \"FixedLen\": [" << 10 << ", " << 69 << "]}" << std::endl;
+  insertJsonValues("table_a", oss.str());
+
+  createTable("table_b",
+              {{"si", ctx().int8()}, {"FixedLen", ctx().arrayFixed(2, ctx().int32())}},
+              {2});
+
+  std::ostringstream oss_2;
+  oss_2 << "{\"si\": 1, \"FixedLen\": [" << 2 << ", " << 33 << "]}" << std::endl;
+  oss_2 << "{\"si\": 2, \"FixedLen\": [" << 1 << ", " << 17 << "]}" << std::endl;
+  oss_2 << "{\"si\": 2, \"FixedLen\": [" << 6 << ", " << 48 << "]}" << std::endl;
+  oss_2 << "{\"si\": 3, \"FixedLen\": [" << 7 << ", " << 49 << "]}" << std::endl;
+  oss_2 << "{\"si\": 4, \"FixedLen\": [" << 8 << ", " << 67 << "]}" << std::endl;
+  oss_2 << "{\"si\": 5, \"FixedLen\": [" << 9 << ", " << 68 << "]}" << std::endl;
+  oss_2 << "{\"si\": 6, \"FixedLen\": [" << 10 << ", " << 69 << "]}" << std::endl;
+  insertJsonValues("table_b", oss_2.str());
+
+  EXPECT_NO_THROW(run_multiple_agg(R"(
+        SELECT * FROM table_a, table_b WHERE table_a.si = table_b.si;
+      )",
+                                   ExecutorDeviceType::CPU));
+
+  dropTable("table_a");
+  dropTable("table_b");
+}
+
+TEST(Other, FixedLenArr2) {
+  config().rs.enable_lazy_fetch = false;
+
+  createTable("table_a",
+              {{"si", ctx().int16()}, {"FixedLen", ctx().arrayFixed(2, ctx().int16())}},
+              {1});
+
+  std::ostringstream oss;
+  oss << "{\"si\": 1, \"FixedLen\": [" << 7 << ", " << 233 << "]}" << std::endl;
+  oss << "{\"si\": 1, \"FixedLen\": [" << 5 << ", " << 47 << "]}" << std::endl;
+  oss << "{\"si\": 2, \"FixedLen\": [" << 6 << ", " << 48 << "]}" << std::endl;
+  oss << "{\"si\": 3, \"FixedLen\": [" << 7 << ", " << 49 << "]}" << std::endl;
+  oss << "{\"si\": 4, \"FixedLen\": [" << 8 << ", " << 67 << "]}" << std::endl;
+  oss << "{\"si\": 5, \"FixedLen\": [" << 9 << ", " << 68 << "]}" << std::endl;
+  oss << "{\"si\": 6, \"FixedLen\": [" << 10 << ", " << 69 << "]}" << std::endl;
+  insertJsonValues("table_a", oss.str());
+
+  createTable("table_b",
+              {{"si", ctx().int8()}, {"FixedLen", ctx().arrayFixed(2, ctx().int32())}},
+              {2});
+
+  std::ostringstream oss_2;
+  oss_2 << "{\"si\": 1, \"FixedLen\": [" << 2 << ", " << 33 << "]}" << std::endl;
+  oss_2 << "{\"si\": 2, \"FixedLen\": [" << 1 << ", " << 17 << "]}" << std::endl;
+  oss_2 << "{\"si\": 2, \"FixedLen\": [" << 6 << ", " << 48 << "]}" << std::endl;
+  oss_2 << "{\"si\": 3, \"FixedLen\": [" << 7 << ", " << 49 << "]}" << std::endl;
+  oss_2 << "{\"si\": 4, \"FixedLen\": [" << 8 << ", " << 67 << "]}" << std::endl;
+  oss_2 << "{\"si\": 5, \"FixedLen\": [" << 9 << ", " << 68 << "]}" << std::endl;
+  oss_2 << "{\"si\": 6, \"FixedLen\": [" << 10 << ", " << 69 << "]}" << std::endl;
+  insertJsonValues("table_b", oss_2.str());
+
+  EXPECT_NO_THROW(run_multiple_agg(R"(
+        SELECT * FROM table_a INNER JOIN table_b ON table_a.FixedLen[1] =
+        table_b.FixedLen[1];
+      )",
+                                   ExecutorDeviceType::CPU));
+
+  dropTable("table_a");
+  dropTable("table_b");
+}
+
 int main(int argc, char** argv) {
   TestHelpers::init_logger_stderr_only(argc, argv);
   testing::InitGoogleTest(&argc, argv);