test-example-projects/c++_projects/280w-mysql-8.0.18/unittest/gunit/hash_join-t.cc

/* Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.

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   You should have received a copy of the GNU General Public License
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   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */

// First include (the generated) my_config.h, to get correct platform defines.
#include "my_config.h"

#include <gtest/gtest.h>

#include <random>
#include <vector>

#include "extra/lz4/my_xxhash.h"
#include "include/my_murmur3.h"
#include "my_alloc.h"
#include "sql/hash_join_buffer.h"
#include "sql/hash_join_iterator.h"
#include "sql/item_cmpfunc.h"
#include "sql/row_iterator.h"
#include "sql/sql_executor.h"
#include "sql/sql_optimizer.h"
#include "sql_string.h"
#include "unittest/gunit/benchmark.h"
#include "unittest/gunit/fake_integer_iterator.h"
#include "unittest/gunit/fake_string_iterator.h"
#include "unittest/gunit/fake_table.h"
#include "unittest/gunit/parsertest.h"
#include "unittest/gunit/temptable/mock_field_long.h"
#include "unittest/gunit/temptable/mock_field_varstring.h"
#include "unittest/gunit/test_utils.h"

namespace hash_join_unittest {

using std::vector;

static hash_join_buffer::TableCollection CreateTenTableJoin(MEM_ROOT *mem_root,
                                                            bool store_data) {
  constexpr int kNumColumns = 10;
  constexpr bool kColumnsNullable = true;
  constexpr int kNumTablesInJoin = 10;

  // Set up a ten-table join. For simplicity, allocate everything on a MEM_ROOT
  // that will take care of releasing allocated memory.
  vector<QEP_TAB *> qep_tabs;
  for (int i = 0; i < kNumTablesInJoin; ++i) {
    Fake_TABLE *fake_table =
        new (mem_root) Fake_TABLE(kNumColumns, kColumnsNullable);
    QEP_TAB *qep_tab = new (mem_root) QEP_TAB;
    qep_tab->set_qs(new (mem_root) QEP_shared);
    qep_tab->set_table(fake_table);
    qep_tab->table_ref = fake_table->pos_in_table_list;

    if (store_data) {
      bitmap_set_all(fake_table->write_set);

      for (uint j = 0; j < fake_table->s->fields; ++j) {
        fake_table->field[j]->store(1000, false /* is_unsigned */);
      }
    }

    qep_tabs.push_back(qep_tab);
  }

  return hash_join_buffer::TableCollection(qep_tabs);
}

static void BM_StoreFromTableBuffersNoData(size_t num_iterations) {
  StopBenchmarkTiming();

  my_testing::Server_initializer initializer;
  initializer.SetUp();
  MEM_ROOT mem_root;
  hash_join_buffer::TableCollection table_collection =
      CreateTenTableJoin(&mem_root, false);

  String buffer;
  buffer.reserve(1024);

  StartBenchmarkTiming();
  for (size_t i = 0; i < num_iterations; ++i) {
    ASSERT_FALSE(
        hash_join_buffer::StoreFromTableBuffers(table_collection, &buffer));
    ASSERT_GT(buffer.length(), 0);
  }
  StopBenchmarkTiming();

  initializer.TearDown();
}
BENCHMARK(BM_StoreFromTableBuffersNoData)

static void BM_StoreFromTableBuffersWithData(size_t num_iterations) {
  StopBenchmarkTiming();

  my_testing::Server_initializer initializer;
  initializer.SetUp();

  MEM_ROOT mem_root;
  hash_join_buffer::TableCollection table_collection =
      CreateTenTableJoin(&mem_root, true);

  String buffer;
  buffer.reserve(1024);

  StartBenchmarkTiming();
  for (size_t i = 0; i < num_iterations; ++i) {
    ASSERT_FALSE(
        hash_join_buffer::StoreFromTableBuffers(table_collection, &buffer));
    ASSERT_GT(buffer.length(), 0);
  }
  StopBenchmarkTiming();

  initializer.TearDown();
}
BENCHMARK(BM_StoreFromTableBuffersWithData)

// Return eight bytes of data.
static vector<uchar> GetShortData() { return {1, 2, 3, 4, 5, 6, 7, 8}; }

// Return 1024 bytes of data.
static vector<uchar> GetLongData() {
  constexpr int kDataSize = 1024;
  vector<uchar> data(kDataSize);
  for (int i = 0; i < kDataSize; ++i) {
    data.push_back(i);
  }
  return data;
}

static void BM_Murmur3ShortData(size_t num_iterations) {
  StopBenchmarkTiming();

  vector<uchar> data = GetShortData();
  StartBenchmarkTiming();

  size_t sum = 0;
  for (size_t i = 0; i < num_iterations; ++i) {
    sum += murmur3_32(&data[0], data.size(), 0);
  }
  StopBenchmarkTiming();

  // The sum variable is just to assure that the compiler doesn't optimize away
  // the entire for loop.
  EXPECT_NE(0, sum);
  SetBytesProcessed(num_iterations * data.size());
}
BENCHMARK(BM_Murmur3ShortData)

static void BM_MurmurLongData(size_t num_iterations) {
  StopBenchmarkTiming();

  vector<uchar> data = GetLongData();
  StartBenchmarkTiming();

  size_t sum = 0;
  for (size_t i = 0; i < num_iterations; ++i) {
    sum += murmur3_32(&data[0], data.size(), 0);
  }
  StopBenchmarkTiming();

  // The sum variable is just to assure that the compiler doesn't optimize away
  // the entire for loop.
  EXPECT_NE(0, sum);
  SetBytesProcessed(num_iterations * data.size());
}
BENCHMARK(BM_MurmurLongData)

static void BM_XXHash64ShortData(size_t num_iterations) {
  StopBenchmarkTiming();

  vector<uchar> data = GetShortData();
  StartBenchmarkTiming();

  size_t sum = 0;
  for (size_t i = 0; i < num_iterations; ++i) {
    sum += MY_XXH64(&data[0], data.size(), 0);
  }
  StopBenchmarkTiming();

  // The sum variable is just to assure that the compiler doesn't optimize away
  // the entire for loop.
  EXPECT_NE(0, sum);
  SetBytesProcessed(num_iterations * data.size());
}
BENCHMARK(BM_XXHash64ShortData)

static void BM_XXHash64LongData(size_t num_iterations) {
  StopBenchmarkTiming();

  vector<uchar> data = GetLongData();
  StartBenchmarkTiming();

  size_t sum = 0;
  for (size_t i = 0; i < num_iterations; ++i) {
    sum += MY_XXH64(&data[0], data.size(), 0);
  }
  StopBenchmarkTiming();

  // The sum variable is just to assure that the compiler doesn't optimize away
  // the entire for loop.
  EXPECT_NE(0, sum);
  SetBytesProcessed(num_iterations * data.size());
}
BENCHMARK(BM_XXHash64LongData)

// A class that takes care of setting up an environment for testing a hash join
// iterator. The constructors will set up two tables (left and right), as well
// as two (fake) iterators that reads data from these two tables. Both tables
// has only one column, and the join condition between the two tables is a
// simple equality between these two columns. There are two different
// constructors; one for integer data sets and one for string data sets.
//
// The user must provide the data contents for both tables in the constructor.
class HashJoinTestHelper {
 public:
  unique_ptr_destroy_only<RowIterator> left_iterator;
  unique_ptr_destroy_only<RowIterator> right_iterator;
  QEP_TAB *left_qep_tab;
  QEP_TAB *right_qep_tab;
  Item_func_eq *join_condition;

  HashJoinTestHelper(Server_initializer *initializer,
                     const vector<int> &left_dataset,
                     const vector<int> &right_dataset) {
    m_left_table_field.reset(
        new (&m_mem_root) Mock_field_long("column1", false /* is_nullable */));
    Fake_TABLE *left_table =
        new (&m_mem_root) Fake_TABLE(m_left_table_field.get());

    m_right_table_field.reset(
        new (&m_mem_root) Mock_field_long("column1", false /* is_nullable */));
    Fake_TABLE *right_table =
        new (&m_mem_root) Fake_TABLE(m_right_table_field.get());
    SetupFakeTables(initializer, left_table, right_table);

    left_iterator.reset(new (&m_mem_root) FakeIntegerIterator(
        initializer->thd(), left_table,
        down_cast<Field_long *>(left_table->field[0]), move(left_dataset)));
    right_iterator.reset(new (&m_mem_root) FakeIntegerIterator(
        initializer->thd(), right_table,
        down_cast<Field_long *>(right_table->field[0]), move(right_dataset)));
  }

  HashJoinTestHelper(Server_initializer *initializer,
                     const vector<std::string> &left_dataset,
                     const vector<std::string> &right_dataset) {
    m_left_table_field.reset(new (&m_mem_root) Mock_field_varstring(
        nullptr, "column1", 255 /* length */, false /* is_nullable */));
    Fake_TABLE *left_table =
        new (&m_mem_root) Fake_TABLE(m_left_table_field.get());

    m_right_table_field.reset(new (&m_mem_root) Mock_field_varstring(
        nullptr, "column1", 255 /* length */, false /* is_nullable */));
    Fake_TABLE *right_table =
        new (&m_mem_root) Fake_TABLE(m_right_table_field.get());
    SetupFakeTables(initializer, left_table, right_table);

    left_iterator.reset(new (&m_mem_root) FakeStringIterator(
        initializer->thd(), left_table,
        down_cast<Field_varstring *>(left_table->field[0]),
        move(left_dataset)));
    right_iterator.reset(new (&m_mem_root) FakeStringIterator(
        initializer->thd(), right_table,
        down_cast<Field_varstring *>(right_table->field[0]),
        move(right_dataset)));
  }

 private:
  void SetupFakeTables(Server_initializer *initializer, Fake_TABLE *left_table,
                       Fake_TABLE *right_table) {
    bitmap_set_all(left_table->write_set);
    bitmap_set_all(left_table->read_set);
    bitmap_set_all(right_table->write_set);
    bitmap_set_all(right_table->read_set);

    SELECT_LEX *select_lex =
        parse(initializer,
              "SELECT * FROM t1 JOIN t2 ON (t1.column1 = t2.column1);", 0);
    JOIN *join = new (&m_mem_root) JOIN(initializer->thd(), select_lex);

    left_qep_tab = new (&m_mem_root) QEP_TAB;
    left_qep_tab->set_qs(new (&m_mem_root) QEP_shared);
    left_qep_tab->set_table(left_table);
    left_qep_tab->table_ref = left_table->pos_in_table_list;
    left_qep_tab->set_join(join);

    right_qep_tab = new (&m_mem_root) QEP_TAB;
    right_qep_tab->set_qs(new (&m_mem_root) QEP_shared);
    right_qep_tab->set_table(right_table);
    right_qep_tab->table_ref = right_table->pos_in_table_list;
    right_qep_tab->set_join(join);

    join_condition = new Item_func_eq(new Item_field(left_table->field[0]),
                                      new Item_field(right_table->field[0]));
    join_condition->set_cmp_func();
  }

  // For simplicity, we allocate everything on a MEM_ROOT that takes care of
  // releasing any memory. However, we must ensure that the destructor is called
  // for Mock_field_varstring. Wrapping the fields in a unique_ptr_destroy_only
  // will ensure this.
  MEM_ROOT m_mem_root;
  unique_ptr_destroy_only<Field> m_left_table_field;
  unique_ptr_destroy_only<Field> m_right_table_field;
};

TEST(HashJoinTest, JoinIntOneToOneMatch) {
  my_testing::Server_initializer initializer;
  initializer.SetUp();

  vector<int> left_data;
  left_data.push_back(3);

  vector<int> right_data;
  right_data.push_back(3);

  HashJoinTestHelper test_helper(&initializer, left_data, right_data);

  HashJoinIterator hash_join_iterator(
      initializer.thd(), std::move(test_helper.left_iterator),
      {test_helper.left_qep_tab}, std::move(test_helper.right_iterator),
      test_helper.right_qep_tab, 10 * 1024 * 1024 /* 10 MB */,
      {test_helper.join_condition}, true);

  ASSERT_FALSE(hash_join_iterator.Init());

  EXPECT_EQ(0, hash_join_iterator.Read());
  EXPECT_EQ(3, test_helper.left_qep_tab->table()->field[0]->val_int());
  EXPECT_EQ(-1, hash_join_iterator.Read());

  initializer.TearDown();
}

TEST(HashJoinTest, JoinIntNoMatch) {
  my_testing::Server_initializer initializer;
  initializer.SetUp();

  HashJoinTestHelper test_helper(&initializer, {2, 4}, {3, 5});

  HashJoinIterator hash_join_iterator(
      initializer.thd(), std::move(test_helper.left_iterator),
      {test_helper.left_qep_tab}, std::move(test_helper.right_iterator),
      test_helper.right_qep_tab, 10 * 1024 * 1024 /* 10 MB */,
      {test_helper.join_condition}, true);

  ASSERT_FALSE(hash_join_iterator.Init());
  EXPECT_EQ(-1, hash_join_iterator.Read());
  initializer.TearDown();
}

TEST(HashJoinTest, JoinIntOneToManyMatch) {
  my_testing::Server_initializer initializer;
  initializer.SetUp();

  HashJoinTestHelper test_helper(&initializer, {2}, {2, 2});

  HashJoinIterator hash_join_iterator(
      initializer.thd(), std::move(test_helper.left_iterator),
      {test_helper.left_qep_tab}, std::move(test_helper.right_iterator),
      test_helper.right_qep_tab, 10 * 1024 * 1024 /* 10 MB */,
      {test_helper.join_condition}, true);

  ASSERT_FALSE(hash_join_iterator.Init());

  // We expect two result rows before the iterator should return -1 (EOF).
  EXPECT_EQ(0, hash_join_iterator.Read());
  EXPECT_EQ(2, test_helper.left_qep_tab->table()->field[0]->val_int());

  EXPECT_EQ(0, hash_join_iterator.Read());
  EXPECT_EQ(2, test_helper.left_qep_tab->table()->field[0]->val_int());

  EXPECT_EQ(-1, hash_join_iterator.Read());
  initializer.TearDown();
}

TEST(HashJoinTest, JoinStringOneToOneMatch) {
  my_testing::Server_initializer initializer;
  initializer.SetUp();

  HashJoinTestHelper test_helper(&initializer, {"abc"}, {"abc"});

  HashJoinIterator hash_join_iterator(
      initializer.thd(), std::move(test_helper.left_iterator),
      {test_helper.left_qep_tab}, std::move(test_helper.right_iterator),
      test_helper.right_qep_tab, 10 * 1024 * 1024 /* 10 MB */,
      {test_helper.join_condition}, true);

  ASSERT_FALSE(hash_join_iterator.Init());

  EXPECT_EQ(0, hash_join_iterator.Read());
  String buffer;
  String *result =
      test_helper.left_qep_tab->table()->field[0]->val_str(&buffer);
  EXPECT_EQ(std::string(result->ptr(), result->length()), std::string("abc"));

  EXPECT_EQ(-1, hash_join_iterator.Read());
  initializer.TearDown();
}

// Do a benchmark of HashJoinIterator::Init(). This function is responsible for
// building the hash table, and this step is also known as the "build phase".
//
// The table that the hash table is built from is a single-column table with
// 10000 uniformly distributed values between [0, 10000). We give the hash table
// enough memory so that it doesn't spill out to disk.
static void BM_HashTableIteratorBuild(size_t num_iterations) {
  StopBenchmarkTiming();

  my_testing::Server_initializer initializer;
  initializer.SetUp();

  const int min_value = 0;
  const int max_value = 10000;
  const int seed = 8834245;
  std::mt19937 generator(seed);
  std::uniform_int_distribution<> distribution(min_value, max_value);

  vector<int> left_dataset;
  vector<int> right_dataset;
  for (int i = 0; i < (max_value - min_value); ++i) {
    left_dataset.push_back(distribution(generator));
    right_dataset.push_back(distribution(generator));
  }

  HashJoinTestHelper test_helper(&initializer, left_dataset, right_dataset);

  HashJoinIterator hash_join_iterator(
      initializer.thd(), std::move(test_helper.left_iterator),
      {test_helper.left_qep_tab}, std::move(test_helper.right_iterator),
      test_helper.right_qep_tab, 10 * 1024 * 1024 /* 10 MB */,
      {test_helper.join_condition}, true);

  StartBenchmarkTiming();
  for (size_t i = 0; i < num_iterations; ++i) {
    ASSERT_FALSE(hash_join_iterator.Init());
  }
  StopBenchmarkTiming();

  initializer.TearDown();
}
BENCHMARK(BM_HashTableIteratorBuild)

// Do a benchmark of HashJoinIterator::Read(). This function will read a row
// from the right table, and look for a matching row in the hash table. This is
// also known as the "probe phase".
//
// The table that the hash table is built from is a single-column table with
// 10000 uniformly distributed values between [0, 10000). We give the hash table
// enough memory so that is doesn't spill out to disk.
static void BM_HashTableIteratorProbe(size_t num_iterations) {
  StopBenchmarkTiming();

  my_testing::Server_initializer initializer;
  initializer.SetUp();

  const int min_value = 0;
  const int max_value = 10000;
  const int seed = 8834245;
  std::mt19937 generator(seed);
  std::uniform_int_distribution<> distribution(min_value, max_value);

  vector<int> left_dataset;
  vector<int> right_dataset;
  for (int i = 0; i < (max_value - min_value); ++i) {
    left_dataset.push_back(distribution(generator));
    right_dataset.push_back(distribution(generator));
  }
  HashJoinTestHelper test_helper(&initializer, left_dataset, right_dataset);

  HashJoinIterator hash_join_iterator(
      initializer.thd(), std::move(test_helper.left_iterator),
      {test_helper.left_qep_tab}, std::move(test_helper.right_iterator),
      test_helper.right_qep_tab, 10 * 1024 * 1024 /* 10 MB */,
      {test_helper.join_condition}, true);

  for (size_t i = 0; i < num_iterations; ++i) {
    ASSERT_FALSE(hash_join_iterator.Init());
    StartBenchmarkTiming();
    int result;
    do {
      result = hash_join_iterator.Read();
    } while (result == 0);
    StopBenchmarkTiming();
  }

  initializer.TearDown();
}
BENCHMARK(BM_HashTableIteratorProbe)

}  // namespace hash_join_unittest