[Join] InitHashTable optimisation

omniscidb/QueryEngine/CMakeLists.txt

@@ -61,6 +61,7 @@ set(query_engine_source_files
     JoinHashTable/HashTable.cpp
     JoinHashTable/PerfectJoinHashTable.cpp
     JoinHashTable/Runtime/HashJoinRuntime.cpp
+    JoinHashTable/Runtime/HashJoinRuntimeCpu.cpp
     L0Kernel.cpp
     LogicalIR.cpp
     LLVMFunctionAttributesUtil.cpp

omniscidb/QueryEngine/ColumnFetcher.cpp

@@ -146,8 +146,8 @@ JoinColumn ColumnFetcher::makeJoinColumn(
         data_provider,
         column_cache);
     if (col_buff != nullptr) {
+      join_chunk_array[num_chunks] = JoinChunk{col_buff, elem_count, num_elems};
       num_elems += elem_count;
-      join_chunk_array[num_chunks] = JoinChunk{col_buff, elem_count};
     } else {
       continue;
     }

omniscidb/QueryEngine/JoinHashTable/Builders/PerfectHashTableBuilder.h

@@ -17,6 +17,7 @@
 #pragma once
 
 #include "QueryEngine/JoinHashTable/PerfectHashTable.h"
+#include "QueryEngine/JoinHashTable/Runtime/HashJoinRuntimeCpu.h"
 
 #include "Shared/scope.h"
 
@@ -166,8 +167,6 @@ class PerfectJoinHashTableBuilder {
                                            0);
 
     auto cpu_hash_table_buff = reinterpret_cast<int32_t*>(hash_table_->getCpuBuffer());
-    const int thread_count = cpu_threads();
-    std::vector<std::thread> init_cpu_buff_threads;
 
     {
       auto timer_init = DEBUG_TIMER("CPU One-To-One Perfect-Hash: init_hash_join_buff");
@@ -176,54 +175,36 @@ class PerfectJoinHashTableBuilder {
                           hash_join_invalid_val);
     }
     const bool for_semi_join = for_semi_anti_join(join_type);
-    std::atomic<int> err{0};
     {
       auto timer_fill =
-          DEBUG_TIMER("CPU One-To-One Perfect-Hash: fill_hash_join_buff_bucketized");
-      for (int thread_idx = 0; thread_idx < thread_count; ++thread_idx) {
-        init_cpu_buff_threads.emplace_back([hash_join_invalid_val,
-                                            &join_column,
-                                            str_proxy_translation_map,
-                                            thread_idx,
-                                            thread_count,
-                                            type,
-                                            &err,
-                                            &col_range,
-                                            &is_bitwise_eq,
-                                            &for_semi_join,
-                                            cpu_hash_table_buff,
-                                            hash_entry_info] {
-          int partial_err = fill_hash_join_buff_bucketized(
-              cpu_hash_table_buff,
-              hash_join_invalid_val,
-              for_semi_join,
-              join_column,
-              {static_cast<size_t>(type->size()),
-               col_range.getIntMin(),
-               col_range.getIntMax(),
-               inline_fixed_encoding_null_value(type),
-               is_bitwise_eq,
-               col_range.getIntMax() + 1,
-               get_join_column_type_kind(type)},
-              str_proxy_translation_map ? str_proxy_translation_map->data() : nullptr,
-              str_proxy_translation_map ? str_proxy_translation_map->domainStart()
-                                        : 0,  // 0 is dummy value
-              thread_idx,
-              thread_count,
-              hash_entry_info.bucket_normalization);
-          int zero{0};
-          err.compare_exchange_strong(zero, partial_err);
-        });
-      }
-      for (auto& t : init_cpu_buff_threads) {
-        t.join();
+          DEBUG_TIMER("CPU One-To-One Perfect-Hash: fill_hash_join_buff_bucketized_cpu");
+
+      {
+        JoinColumnTypeInfo type_info{static_cast<size_t>(type->size()),
+                                     col_range.getIntMin(),
+                                     col_range.getIntMax(),
+                                     inline_fixed_encoding_null_value(type),
+                                     is_bitwise_eq,
+                                     col_range.getIntMax() + 1,
+                                     get_join_column_type_kind(type)};
+
+        int error = fill_hash_join_buff_bucketized_cpu(
+            cpu_hash_table_buff,
+            hash_join_invalid_val,
+            for_semi_join,
+            join_column,
+            type_info,
+            str_proxy_translation_map ? str_proxy_translation_map->data() : nullptr,
+            str_proxy_translation_map ? str_proxy_translation_map->domainStart()
+                                      : 0,  // 0 is dummy value
+            hash_entry_info.bucket_normalization);
+        if (error) {
+          // Too many hash entries, need to retry with a 1:many table
+          hash_table_ = nullptr;  // clear the hash table buffer
+          throw NeedsOneToManyHash();
+        }
       }
     }
-    if (err) {
-      // Too many hash entries, need to retry with a 1:many table
-      hash_table_ = nullptr;  // clear the hash table buffer
-      throw NeedsOneToManyHash();
-    }
   }
 
   void initOneToManyHashTableOnCpu(

omniscidb/QueryEngine/JoinHashTable/Runtime/HashJoinRuntime.cpp

@@ -28,6 +28,7 @@
 #else
 #include "Logger/Logger.h"
 
+#include "HashJoinRuntimeCpu.h"
 #include "QueryEngine/RuntimeFunctions.h"
 #include "Shared/likely.h"
 #include "StringDictionary/StringDictionary.h"
@@ -53,56 +54,6 @@
 #ifndef __CUDACC__
 namespace {
 
-/**
- * Joins between two dictionary encoded string columns without a shared string dictionary
- * are computed by translating the inner dictionary to the outer dictionary while filling
- * the  hash table. The translation works as follows:
- *
- * Given two tables t1 and t2, with t1 the outer table and t2 the inner table, and two
- * columns t1.x and t2.x, both dictionary encoded strings without a shared dictionary, we
- * read each value in t2.x and do a lookup in the dictionary for t1.x. If the lookup
- * returns a valid ID, we insert that ID into the hash table. Otherwise, we skip adding an
- * entry into the hash table for the inner column. We can also skip adding any entries
- * that are outside the range of the outer column.
- *
- * Consider a join of the form SELECT x, n FROM (SELECT x, COUNT(*) n FROM t1 GROUP BY x
- * HAVING n > 10), t2 WHERE t1.x = t2.x; Let the result of the subquery be t1_s.
- * Due to the HAVING clause, the range of all IDs in t1_s must be less than or equal to
- * the range of all IDs in t1. Suppose we have an element a in t2.x that is also in
- * t1_s.x. Then the ID of a must be within the range of t1_s. Therefore it is safe to
- * ignore any element ID that is not in the dictionary corresponding to t1_s.x or is
- * outside the range of column t1_s.
- */
-inline int64_t translate_str_id_to_outer_dict(const int64_t elem,
-                                              const int64_t min_elem,
-                                              const int64_t max_elem,
-                                              const void* sd_inner_proxy,
-                                              const void* sd_outer_proxy) {
-  CHECK(sd_outer_proxy);
-  const auto sd_inner_dict_proxy =
-      static_cast<const StringDictionaryProxy*>(sd_inner_proxy);
-  const auto sd_outer_dict_proxy =
-      static_cast<const StringDictionaryProxy*>(sd_outer_proxy);
-  const auto elem_str = sd_inner_dict_proxy->getString(elem);
-  const auto outer_id = sd_outer_dict_proxy->getIdOfString(elem_str);
-  if (outer_id > max_elem || outer_id < min_elem) {
-    return StringDictionary::INVALID_STR_ID;
-  }
-  return outer_id;
-}
-
-inline int64_t map_str_id_to_outer_dict(const int64_t inner_elem,
-                                        const int64_t min_inner_elem,
-                                        const int64_t min_outer_elem,
-                                        const int64_t max_outer_elem,
-                                        const int32_t* inner_to_outer_translation_map) {
-  const auto outer_id = inner_to_outer_translation_map[inner_elem - min_inner_elem];
-  if (outer_id > max_outer_elem || outer_id < min_outer_elem) {
-    return StringDictionary::INVALID_STR_ID;
-  }
-  return outer_id;
-}
-
 #if defined(_MSC_VER)
 #define DEFAULT_TARGET_ATTRIBUTE
 #else

omniscidb/QueryEngine/JoinHashTable/Runtime/HashJoinRuntime.h

@@ -101,6 +101,7 @@ struct JoinChunk {
   const int8_t*
       col_buff;  // actually from AbstractBuffer::getMemoryPtr() via Chunk_NS::Chunk
   size_t num_elems;
+  size_t row_id;
 };
 
 struct JoinColumn {