Adding support for equi-join on struct (#7720)

Adds support for equijoin on structs.

This PR is leveraging the [struct PR](#7422) and the [rewrite for join API](#7454). It enables equijoin on structs by flattening the struct for the hash calculation.

closes #7543

Authors:
  - Mike Wilson (https://github.com/hyperbolic2346)
  - Ashwin Srinath (https://github.com/shwina)
  - Karthikeyan (https://github.com/karthikeyann)
  - Vukasin Milovanovic (https://github.com/vuule)
  - Alessandro Bellina (https://github.com/abellina)
  - Devavret Makkar (https://github.com/devavret)
  - David Wendt (https://github.com/davidwendt)
  - Liangcai Li (https://github.com/firestarman)
  - Paul Taylor (https://github.com/trxcllnt)
  - Kumar Aatish (https://github.com/kaatish)
  - Jason Lowe (https://github.com/jlowe)
  - Dillon Cullinan (https://github.com/dillon-cullinan)
  - Raza Jafri (https://github.com/razajafri)
  - https://github.com/rwlee
  - Michael Wang (https://github.com/isVoid)
  - Dante Gama Dessavre (https://github.com/dantegd)
  - Keith Kraus (https://github.com/kkraus14)
  - Robert Maynard (https://github.com/robertmaynard)
  - GALI PREM SAGAR (https://github.com/galipremsagar)
  - https://github.com/ChrisJar
  - AJ Schmidt (https://github.com/ajschmidt8)
  - https://github.com/nvdbaranec
  - Nghia Truong (https://github.com/ttnghia)
  - https://github.com/chenrui17
  - Conor Hoekstra (https://github.com/codereport)
  - Mike Wendt (https://github.com/mike-wendt)

Approvers:
  - Nghia Truong (https://github.com/ttnghia)
  - Devavret Makkar (https://github.com/devavret)
  - Jake Hemstad (https://github.com/jrhemstad)

URL: #7720

cpp/src/join/hash_join.cu

@@ -15,6 +15,7 @@
  */
 #include <thrust/uninitialized_fill.h>
 #include <join/hash_join.cuh>
+#include <structs/utilities.hpp>
 
 #include <cudf/detail/concatenate.cuh>
 #include <cudf/detail/gather.cuh>
@@ -299,13 +300,15 @@ hash_join::hash_join_impl::~hash_join_impl() = default;
 hash_join::hash_join_impl::hash_join_impl(cudf::table_view const &build,
                                           null_equality compare_nulls,
                                           rmm::cuda_stream_view stream)
-  : _build(build), _hash_table(nullptr)
+  : _hash_table(nullptr)
 {
   CUDF_FUNC_RANGE();
-  CUDF_EXPECTS(0 != _build.num_columns(), "Hash join build table is empty");
-  CUDF_EXPECTS(_build.num_rows() < cudf::detail::MAX_JOIN_SIZE,
+  CUDF_EXPECTS(0 != build.num_columns(), "Hash join build table is empty");
+  CUDF_EXPECTS(build.num_rows() < cudf::detail::MAX_JOIN_SIZE,
                "Build column size is too big for hash join");
 
+  _build = std::get<0>(structs::detail::flatten_nested_columns(build, {}, {}));
+
   if (0 == build.num_rows()) { return; }
 
   _hash_table = build_join_hash_table(_build, compare_nulls, stream);
@@ -355,22 +358,25 @@ hash_join::hash_join_impl::compute_hash_join(cudf::table_view const &probe,
   CUDF_EXPECTS(0 != probe.num_columns(), "Hash join probe table is empty");
   CUDF_EXPECTS(probe.num_rows() < cudf::detail::MAX_JOIN_SIZE,
                "Probe column size is too big for hash join");
-  CUDF_EXPECTS(_build.num_columns() == probe.num_columns(),
+
+  auto const _probe = std::get<0>(structs::detail::flatten_nested_columns(probe, {}, {}));
+
+  CUDF_EXPECTS(_build.num_columns() == _probe.num_columns(),
                "Mismatch in number of columns to be joined on");
 
-  if (is_trivial_join(probe, _build, JoinKind)) {
+  if (is_trivial_join(_probe, _build, JoinKind)) {
     return std::make_pair(std::make_unique<rmm::device_uvector<size_type>>(0, stream, mr),
                           std::make_unique<rmm::device_uvector<size_type>>(0, stream, mr));
   }
 
   CUDF_EXPECTS(std::equal(std::cbegin(_build),
                           std::cend(_build),
-                          std::cbegin(probe),
-                          std::cend(probe),
+                          std::cbegin(_probe),
+                          std::cend(_probe),
                           [](const auto &b, const auto &p) { return b.type() == p.type(); }),
                "Mismatch in joining column data types");
 
-  return probe_join_indices<JoinKind>(probe, compare_nulls, stream, mr);
+  return probe_join_indices<JoinKind>(_probe, compare_nulls, stream, mr);
 }
 
 template <cudf::detail::join_kind JoinKind>

cpp/tests/join/join_tests.cpp

@@ -410,6 +410,97 @@ TEST_F(JoinTest, LeftJoinWithNulls)
   CUDF_TEST_EXPECT_TABLES_EQUIVALENT(*sorted_gold, *sorted_result);
 }
 
+TEST_F(JoinTest, LeftJoinWithStructsAndNulls)
+{
+  column_wrapper<int32_t> col0_0{{3, 1, 2, 0, 2}};
+  strcol_wrapper col0_1({"s1", "s1", "", "s4", "s0"}, {1, 1, 0, 1, 1});
+  column_wrapper<int32_t> col0_2{{0, 1, 2, 4, 1}};
+  auto col0_names_col = strcol_wrapper{
+    "Samuel Vimes", "Carrot Ironfoundersson", "Detritus", "Samuel Vimes", "Angua von Überwald"};
+  auto col0_ages_col = column_wrapper<int32_t>{{48, 27, 351, 31, 25}};
+
+  auto col0_is_human_col = column_wrapper<bool>{{true, true, false, false, false}, {1, 1, 0, 1, 0}};
+
+  auto col0_3 =
+    cudf::test::structs_column_wrapper{{col0_names_col, col0_ages_col, col0_is_human_col}};
+
+  column_wrapper<int32_t> col1_0{{2, 2, 0, 4, 3}};
+  strcol_wrapper col1_1({"s1", "s0", "s1", "s2", "s1"});
+  column_wrapper<int32_t> col1_2{{1, 0, 1, 2, 1}, {1, 0, 1, 1, 1}};
+  auto col1_names_col = strcol_wrapper{
+    "Samuel Vimes", "Detritus", "Detritus", "Carrot Ironfoundersson", "Angua von Überwald"};
+  auto col1_ages_col = column_wrapper<int32_t>{{48, 35, 351, 22, 25}};
+
+  auto col1_is_human_col = column_wrapper<bool>{{true, true, false, false, true}, {1, 1, 0, 1, 1}};
+
+  auto col1_3 =
+    cudf::test::structs_column_wrapper{{col1_names_col, col1_ages_col, col1_is_human_col}};
+
+  CVector cols0, cols1;
+  cols0.push_back(col0_0.release());
+  cols0.push_back(col0_1.release());
+  cols0.push_back(col0_2.release());
+  cols0.push_back(col0_3.release());
+  cols1.push_back(col1_0.release());
+  cols1.push_back(col1_1.release());
+  cols1.push_back(col1_2.release());
+  cols1.push_back(col1_3.release());
+
+  Table t0(std::move(cols0));
+  Table t1(std::move(cols1));
+
+  auto result            = cudf::left_join(t0, t1, {3}, {3});
+  auto result_sort_order = cudf::sorted_order(result->view());
+  auto sorted_result     = cudf::gather(result->view(), *result_sort_order);
+
+  column_wrapper<int32_t> col_gold_0{{3, 2, 1, 0, 2}, {1, 1, 1, 1, 1}};
+  strcol_wrapper col_gold_1({"s1", "", "s1", "s4", "s0"}, {1, 0, 1, 1, 1});
+  column_wrapper<int32_t> col_gold_2{{0, 2, 1, 4, 1}, {1, 1, 1, 1, 1}};
+  auto col0_gold_names_col = strcol_wrapper{
+    "Samuel Vimes", "Detritus", "Carrot Ironfoundersson", "Samuel Vimes", "Angua von Überwald"};
+  auto col0_gold_ages_col = column_wrapper<int32_t>{{48, 351, 27, 31, 25}};
+
+  auto col0_gold_is_human_col =
+    column_wrapper<bool>{{true, false, true, false, false}, {1, 0, 1, 1, 0}};
+
+  auto col_gold_3 = cudf::test::structs_column_wrapper{
+    {col0_gold_names_col, col0_gold_ages_col, col0_gold_is_human_col}};
+
+  column_wrapper<int32_t> col_gold_4{{2, 0, -1, -1, -1}, {1, 1, 0, 0, 0}};
+  strcol_wrapper col_gold_5{{"s1", "s1", "", "", ""}, {1, 1, 0, 0, 0}};
+  column_wrapper<int32_t> col_gold_6{{1, 1, -1, -1, -1}, {1, 1, 0, 0, 0}};
+  auto col1_gold_names_col = strcol_wrapper{{
+                                              "Samuel Vimes",
+                                              "Detritus",
+                                              "",
+                                              "",
+                                              "",
+                                            },
+                                            {1, 1, 0, 0, 0}};
+  auto col1_gold_ages_col  = column_wrapper<int32_t>{{48, 351, -1, -1, -1}, {1, 1, 0, 0, 0}};
+
+  auto col1_gold_is_human_col =
+    column_wrapper<bool>{{true, false, false, false, false}, {1, 0, 0, 0, 0}};
+
+  auto col_gold_7 = cudf::test::structs_column_wrapper{
+    {col1_gold_names_col, col1_gold_ages_col, col1_gold_is_human_col}, {1, 1, 0, 0, 0}};
+
+  CVector cols_gold;
+  cols_gold.push_back(col_gold_0.release());
+  cols_gold.push_back(col_gold_1.release());
+  cols_gold.push_back(col_gold_2.release());
+  cols_gold.push_back(col_gold_3.release());
+  cols_gold.push_back(col_gold_4.release());
+  cols_gold.push_back(col_gold_5.release());
+  cols_gold.push_back(col_gold_6.release());
+  cols_gold.push_back(col_gold_7.release());
+  Table gold(std::move(cols_gold));
+
+  auto gold_sort_order = cudf::sorted_order(gold.view());
+  auto sorted_gold     = cudf::gather(gold.view(), *gold_sort_order);
+  CUDF_TEST_EXPECT_TABLES_EQUIVALENT(*sorted_gold, *sorted_result);
+}
+
 TEST_F(JoinTest, LeftJoinOnNulls)
 {
   // clang-format off
@@ -629,6 +720,91 @@ TEST_F(JoinTest, InnerJoinWithNulls)
   CUDF_TEST_EXPECT_TABLES_EQUIVALENT(*sorted_gold, *sorted_result);
 }
 
+TEST_F(JoinTest, InnerJoinWithStructsAndNulls)
+{
+  column_wrapper<int32_t> col0_0{{3, 1, 2, 0, 2}};
+  strcol_wrapper col0_1({"s1", "s1", "s0", "s4", "s0"}, {1, 1, 0, 1, 1});
+  column_wrapper<int32_t> col0_2{{0, 1, 2, 4, 1}};
+  std::initializer_list<std::string> col0_names = {
+    "Samuel Vimes", "Carrot Ironfoundersson", "Detritus", "Samuel Vimes", "Angua von Überwald"};
+  auto col0_names_col = strcol_wrapper{col0_names.begin(), col0_names.end()};
+  auto col0_ages_col  = column_wrapper<int32_t>{{48, 27, 351, 31, 25}};
+
+  auto col0_is_human_col = column_wrapper<bool>{{true, true, false, false, false}, {1, 1, 0, 1, 0}};
+
+  auto col0_3 =
+    cudf::test::structs_column_wrapper{{col0_names_col, col0_ages_col, col0_is_human_col}};
+
+  column_wrapper<int32_t> col1_0{{2, 2, 0, 4, 3}};
+  strcol_wrapper col1_1({"s1", "s0", "s1", "s2", "s1"});
+  column_wrapper<int32_t> col1_2{{1, 0, 1, 2, 1}, {1, 0, 1, 1, 1}};
+  std::initializer_list<std::string> col1_names = {"Carrot Ironfoundersson",
+                                                   "Angua von Überwald",
+                                                   "Detritus",
+                                                   "Carrot Ironfoundersson",
+                                                   "Samuel Vimes"};
+  auto col1_names_col = strcol_wrapper{col1_names.begin(), col1_names.end()};
+  auto col1_ages_col  = column_wrapper<int32_t>{{351, 25, 27, 31, 48}};
+
+  auto col1_is_human_col = column_wrapper<bool>{{true, false, false, false, true}, {1, 0, 0, 1, 1}};
+
+  auto col1_3 =
+    cudf::test::structs_column_wrapper{{col1_names_col, col1_ages_col, col1_is_human_col}};
+
+  CVector cols0, cols1;
+  cols0.push_back(col0_0.release());
+  cols0.push_back(col0_1.release());
+  cols0.push_back(col0_2.release());
+  cols0.push_back(col0_3.release());
+  cols1.push_back(col1_0.release());
+  cols1.push_back(col1_1.release());
+  cols1.push_back(col1_2.release());
+  cols1.push_back(col1_3.release());
+
+  Table t0(std::move(cols0));
+  Table t1(std::move(cols1));
+
+  auto result            = cudf::inner_join(t0, t1, {0, 1, 3}, {0, 1, 3});
+  auto result_sort_order = cudf::sorted_order(result->view());
+  auto sorted_result     = cudf::gather(result->view(), *result_sort_order);
+
+  column_wrapper<int32_t> col_gold_0{{3, 2}};
+  strcol_wrapper col_gold_1({"s1", "s0"}, {1, 1});
+  column_wrapper<int32_t> col_gold_2{{0, 1}};
+  auto col_gold_3_names_col = strcol_wrapper{"Samuel Vimes", "Angua von Überwald"};
+  auto col_gold_3_ages_col  = column_wrapper<int32_t>{{48, 25}};
+
+  auto col_gold_3_is_human_col = column_wrapper<bool>{{true, false}, {1, 0}};
+
+  auto col_gold_3 = cudf::test::structs_column_wrapper{
+    {col_gold_3_names_col, col_gold_3_ages_col, col_gold_3_is_human_col}};
+
+  column_wrapper<int32_t> col_gold_4{{3, 2}};
+  strcol_wrapper col_gold_5({"s1", "s0"}, {1, 1});
+  column_wrapper<int32_t> col_gold_6{{1, -1}, {1, 0}};
+  auto col_gold_7_names_col = strcol_wrapper{"Samuel Vimes", "Angua von Überwald"};
+  auto col_gold_7_ages_col  = column_wrapper<int32_t>{{48, 25}};
+
+  auto col_gold_7_is_human_col = column_wrapper<bool>{{true, false}, {1, 0}};
+
+  auto col_gold_7 = cudf::test::structs_column_wrapper{
+    {col_gold_7_names_col, col_gold_7_ages_col, col_gold_7_is_human_col}};
+  CVector cols_gold;
+  cols_gold.push_back(col_gold_0.release());
+  cols_gold.push_back(col_gold_1.release());
+  cols_gold.push_back(col_gold_2.release());
+  cols_gold.push_back(col_gold_3.release());
+  cols_gold.push_back(col_gold_4.release());
+  cols_gold.push_back(col_gold_5.release());
+  cols_gold.push_back(col_gold_6.release());
+  cols_gold.push_back(col_gold_7.release());
+  Table gold(std::move(cols_gold));
+
+  auto gold_sort_order = cudf::sorted_order(gold.view());
+  auto sorted_gold     = cudf::gather(gold.view(), *gold_sort_order);
+  CUDF_TEST_EXPECT_TABLES_EQUIVALENT(*sorted_gold, *sorted_result);
+}
+
 // // Test to check join behaviour when join keys are null.
 TEST_F(JoinTest, InnerJoinOnNulls)
 {
@@ -1359,4 +1535,128 @@ TEST_F(JoinDictionaryTest, FullJoinWithNulls)
   CUDF_TEST_EXPECT_TABLES_EQUIVALENT(*gold, cudf::table_view(result_decoded));
 }
 
+TEST_F(JoinTest, FullJoinWithStructsAndNulls)
+{
+  column_wrapper<int32_t> col0_0{{3, 1, 2, 0, 3}};
+  strcol_wrapper col0_1({"s0", "s1", "s2", "s4", "s1"});
+  column_wrapper<int32_t> col0_2{{0, 1, 2, 4, 1}};
+
+  std::initializer_list<std::string> col0_names = {"Samuel Vimes",
+                                                   "Carrot Ironfoundersson",
+                                                   "Angua von Überwald",
+                                                   "Detritus",
+                                                   "Carrot Ironfoundersson"};
+  auto col0_names_col = strcol_wrapper{col0_names.begin(), col0_names.end()};
+  auto col0_ages_col  = column_wrapper<int32_t>{{48, 27, 25, 31, 351}};
+
+  auto col0_is_human_col = column_wrapper<bool>{{true, true, false, false, false}, {1, 1, 0, 1, 1}};
+
+  auto col0_3 =
+    cudf::test::structs_column_wrapper{{col0_names_col, col0_ages_col, col0_is_human_col}};
+
+  column_wrapper<int32_t> col1_0{{2, 2, 0, 4, 3}, {1, 1, 1, 0, 1}};
+  strcol_wrapper col1_1{{"s1", "s0", "s1", "s2", "s1"}};
+  column_wrapper<int32_t> col1_2{{1, 0, 1, 2, 1}};
+
+  std::initializer_list<std::string> col1_names = {"Carrot Ironfoundersson",
+                                                   "Samuel Vimes",
+                                                   "Carrot Ironfoundersson",
+                                                   "Angua von Überwald",
+                                                   "Carrot Ironfoundersson"};
+  auto col1_names_col = strcol_wrapper{col1_names.begin(), col1_names.end()};
+  auto col1_ages_col  = column_wrapper<int32_t>{{27, 48, 27, 25, 27}};
+
+  auto col1_is_human_col = column_wrapper<bool>{{true, true, true, false, true}, {1, 1, 1, 0, 1}};
+
+  auto col1_3 =
+    cudf::test::structs_column_wrapper{{col1_names_col, col1_ages_col, col1_is_human_col}};
+
+  CVector cols0, cols1;
+  cols0.push_back(col0_0.release());
+  cols0.push_back(col0_1.release());
+  cols0.push_back(col0_2.release());
+  cols0.push_back(col0_3.release());
+  cols1.push_back(col1_0.release());
+  cols1.push_back(col1_1.release());
+  cols1.push_back(col1_2.release());
+  cols1.push_back(col1_3.release());
+
+  Table t0(std::move(cols0));
+  Table t1(std::move(cols1));
+
+  auto result            = cudf::full_join(t0, t1, {0, 1, 3}, {0, 1, 3});
+  auto result_sort_order = cudf::sorted_order(result->view());
+  auto sorted_result     = cudf::gather(result->view(), *result_sort_order);
+
+  column_wrapper<int32_t> col_gold_0{{3, 1, 2, 0, 3, -1, -1, -1, -1, -1},
+                                     {1, 1, 1, 1, 1, 0, 0, 0, 0, 0}};
+  strcol_wrapper col_gold_1({"s0", "s1", "s2", "s4", "s1", "", "", "", "", ""},
+                            {1, 1, 1, 1, 1, 0, 0, 0, 0, 0});
+  column_wrapper<int32_t> col_gold_2{{0, 1, 2, 4, 1, -1, -1, -1, -1, -1},
+                                     {1, 1, 1, 1, 1, 0, 0, 0, 0, 0}};
+  auto gold_names0_col = strcol_wrapper{{"Samuel Vimes",
+                                         "Carrot Ironfoundersson",
+                                         "Angua von Überwald",
+                                         "Detritus",
+                                         "Carrot Ironfoundersson",
+                                         "",
+                                         "",
+                                         "",
+                                         "",
+                                         ""},
+                                        {1, 1, 1, 1, 1, 0, 0, 0, 0, 0}};
+  auto gold_ages0_col  = column_wrapper<int32_t>{{48, 27, 25, 31, 351, -1, -1, -1, -1, -1},
+                                                {1, 1, 1, 1, 1, 0, 0, 0, 0, 0}};
+
+  auto gold_is_human0_col =
+    column_wrapper<bool>{{true, true, false, false, false, false, false, false, false, false},
+                         {1, 1, 0, 1, 1, 0, 0, 0, 0, 0}};
+
+  auto col_gold_3 = cudf::test::structs_column_wrapper{
+    {gold_names0_col, gold_ages0_col, gold_is_human0_col}, {1, 1, 1, 1, 1, 0, 0, 0, 0, 0}};
+
+  column_wrapper<int32_t> col_gold_4{{-1, -1, -1, -1, -1, 3, 2, 2, 0, 4},
+                                     {0, 0, 0, 0, 0, 1, 1, 1, 1, 0}};
+  strcol_wrapper col_gold_5({"", "", "", "", "", "s1", "s1", "s0", "s1", "s2"},
+                            {0, 0, 0, 0, 0, 1, 1, 1, 1, 1});
+  column_wrapper<int32_t> col_gold_6{{-1, -1, -1, -1, -1, 1, 1, 0, 1, 2},
+                                     {0, 0, 0, 0, 0, 1, 1, 1, 1, 1}};
+  auto gold_names1_col = strcol_wrapper{{"",
+                                         "",
+                                         "",
+                                         "",
+                                         "",
+                                         "Carrot Ironfoundersson",
+                                         "Carrot Ironfoundersson",
+                                         "Samuel Vimes",
+                                         "Carrot Ironfoundersson",
+                                         "Angua von Überwald"},
+                                        {0, 0, 0, 0, 0, 1, 1, 1, 1, 1}};
+  auto gold_ages1_col  = column_wrapper<int32_t>{{-1, -1, -1, -1, -1, 27, 27, 48, 27, 25},
+                                                {0, 0, 0, 0, 0, 1, 1, 1, 1, 1}};
+
+  auto gold_is_human1_col =
+    column_wrapper<bool>{{false, false, false, false, false, true, true, true, true, false},
+                         {0, 0, 0, 0, 0, 1, 1, 1, 1, 0}};
+
+  auto col_gold_7 = cudf::test::structs_column_wrapper{
+    {gold_names1_col, gold_ages1_col, gold_is_human1_col}, {0, 0, 0, 0, 0, 1, 1, 1, 1, 1}};
+
+  CVector cols_gold;
+  cols_gold.push_back(col_gold_0.release());
+  cols_gold.push_back(col_gold_1.release());
+  cols_gold.push_back(col_gold_2.release());
+  cols_gold.push_back(col_gold_3.release());
+  cols_gold.push_back(col_gold_4.release());
+  cols_gold.push_back(col_gold_5.release());
+  cols_gold.push_back(col_gold_6.release());
+  cols_gold.push_back(col_gold_7.release());
+
+  Table gold(std::move(cols_gold));
+
+  auto gold_sort_order = cudf::sorted_order(gold.view());
+  auto sorted_gold     = cudf::gather(gold.view(), *gold_sort_order);
+  CUDF_TEST_EXPECT_TABLES_EQUIVALENT(*sorted_gold, *sorted_result);
+}
+
 CUDF_TEST_PROGRAM_MAIN()