plan, executor: implement Expand operator for grouping sets (#6545)

close #6852, ref pingcap/tidb#16581, ref pingcap/tidb#34704

dbms/src/Common/TiFlashMetrics.h

@@ -61,7 +61,8 @@ namespace DB
         F(type_limit, {"type", "limit"}), F(type_join, {"type", "join"}), F(type_exchange_sender, {"type", "exchange_sender"}),                     \
         F(type_exchange_receiver, {"type", "exchange_receiver"}), F(type_projection, {"type", "projection"}),                                       \
         F(type_partition_ts, {"type", "partition_table_scan"}),                                                                                     \
-        F(type_window, {"type", "window"}), F(type_window_sort, {"type", "window_sort"}))                                                           \
+        F(type_window, {"type", "window"}), F(type_window_sort, {"type", "window_sort"}),                                                           \
+        F(type_expand, {"type", "expand"}))                                                                                                         \
     M(tiflash_coprocessor_request_duration_seconds, "Bucketed histogram of request duration", Histogram,                                            \
         F(type_cop, {{"type", "cop"}}, ExpBuckets{0.001, 2, 20}),                                                                                   \
         F(type_batch, {{"type", "batch"}}, ExpBuckets{0.001, 2, 20}),                                                                               \
@@ -276,7 +277,8 @@ namespace DB
     M(tiflash_compute_request_unit, "Request Unit used by tiflash compute", Counter,                                                                \
         F(type_mpp, {{"type", "mpp"}, ComputeLabelHolder::instance().getClusterIdLabel(), ComputeLabelHolder::instance().getProcessIdLabel()}),     \
         F(type_cop, {{"type", "cop"}, ComputeLabelHolder::instance().getClusterIdLabel(), ComputeLabelHolder::instance().getProcessIdLabel()}),     \
-        F(type_batch, {{"type", "batch"}, ComputeLabelHolder::instance().getClusterIdLabel(), ComputeLabelHolder::instance().getProcessIdLabel()})) \
+        F(type_batch, {{"type", "batch"}, ComputeLabelHolder::instance().getClusterIdLabel(), ComputeLabelHolder::instance().getProcessIdLabel()}))
+
 // clang-format on
 
 /// Buckets with boundaries [start * base^0, start * base^1, ..., start * base^(size-1)]

dbms/src/DataStreams/ExpressionBlockInputStream.cpp

@@ -53,5 +53,4 @@ Block ExpressionBlockInputStream::readImpl()
     expression->execute(res);
     return res;
 }
-
 } // namespace DB

dbms/src/Debug/MockExecutor/ExpandBinder.cpp

@@ -0,0 +1,68 @@
+// Copyright 2022 PingCAP, Ltd.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <Debug/MockExecutor/AstToPBUtils.h>
+#include <Debug/MockExecutor/ExpandBinder.h>
+
+namespace DB::mock
+{
+
+bool ExpandBinder::toTiPBExecutor(tipb::Executor * tipb_executor, int32_t collator_id, const MPPInfo & mpp_info, const Context & context)
+{
+    tipb_executor->set_tp(tipb::ExecType::TypeExpand);
+    tipb_executor->set_executor_id(name);
+    tipb::Expand * expand = tipb_executor->mutable_expand();
+    for (const auto & grouping_set : grouping_sets_columns)
+    {
+        auto * gss = expand->add_grouping_sets();
+        for (const auto & grouping_exprs : grouping_set)
+        {
+            auto * ges = gss->add_grouping_exprs();
+            for (const auto & grouping_col : grouping_exprs)
+            {
+                tipb::Expr * add_column = ges->add_grouping_expr();
+                astToPB(children[0]->output_schema, grouping_col, add_column, collator_id, context); // ast column ref change to tipb:Expr column ref
+            }
+        }
+    }
+    auto * children_executor = expand->mutable_child();
+    return children[0]->toTiPBExecutor(children_executor, collator_id, mpp_info, context);
+}
+
+ExecutorBinderPtr compileExpand(ExecutorBinderPtr input, size_t & executor_index, MockVVecGroupingNameVec grouping_set_columns, std::set<String> in_set)
+{
+    DAGSchema output_schema;
+    for (const auto & field : input->output_schema)
+    {
+        // if the column is in the grouping sets, make it nullable.
+        if (in_set.find(field.first) != in_set.end() && field.second.hasNotNullFlag())
+            output_schema.push_back(toNullableDAGColumnInfo(field));
+        else
+            output_schema.push_back(field);
+    }
+    {
+        tipb::FieldType field_type{};
+        field_type.set_tp(TiDB::TypeLongLong);
+        field_type.set_charset("binary");
+        field_type.set_collate(TiDB::ITiDBCollator::BINARY);
+        field_type.set_flag(TiDB::ColumnFlagUnsigned | TiDB::ColumnFlagNotNull); // should have NOT NULL FLAG
+        field_type.set_flen(-1);
+        field_type.set_decimal(-1);
+        output_schema.push_back(std::make_pair("groupingID", TiDB::fieldTypeToColumnInfo(field_type)));
+    }
+    ExecutorBinderPtr expand = std::make_shared<ExpandBinder>(executor_index, output_schema, std::move(grouping_set_columns));
+    expand->children.push_back(input);
+    return expand;
+}
+} // namespace DB::mock

dbms/src/Debug/MockExecutor/ExpandBinder.h

@@ -0,0 +1,43 @@
+// Copyright 2022 PingCAP, Ltd.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include <Debug/MockExecutor/ExecutorBinder.h>
+
+namespace DB::mock
+{
+using MockGroupingNameVec = std::vector<ASTPtr>;
+using MockVecGroupingNameVec = std::vector<MockGroupingNameVec>;
+using MockVVecGroupingNameVec = std::vector<MockVecGroupingNameVec>;
+
+class ExpandBinder : public ExecutorBinder
+{
+public:
+    ExpandBinder(size_t & index_, const DAGSchema & output_schema_, MockVVecGroupingNameVec gss)
+        : ExecutorBinder(index_, "expand_" + std::to_string(index_), output_schema_)
+        , grouping_sets_columns(gss)
+    {}
+
+    bool toTiPBExecutor(tipb::Executor * tipb_executor, int32_t collator_id, const MPPInfo & mpp_info, const Context & context) override;
+
+    void columnPrune(std::unordered_set<String> &) override { throw Exception("Should not reach here"); }
+
+private:
+    // for now, every grouping set is base columns list, modify structure to be one more nested if grouping set merge is enabled.
+    MockVVecGroupingNameVec grouping_sets_columns;
+};
+
+ExecutorBinderPtr compileExpand(ExecutorBinderPtr input, size_t & executor_index, MockVVecGroupingNameVec grouping_set_columns, std::set<String> set);
+} // namespace DB::mock

dbms/src/Flash/Coprocessor/DAGExpressionAnalyzer.cpp

@@ -32,6 +32,7 @@
 #include <Functions/FunctionHelpers.h>
 #include <Functions/FunctionsTiDBConversion.h>
 #include <Interpreters/Context.h>
+#include <Interpreters/Expand.h>
 #include <Interpreters/Set.h>
 #include <Interpreters/Settings.h>
 #include <Interpreters/convertFieldToType.h>
@@ -804,6 +805,65 @@ NamesAndTypes DAGExpressionAnalyzer::buildOrderColumns(
     return order_columns;
 }
 
+GroupingSets DAGExpressionAnalyzer::buildExpandGroupingColumns(
+    const tipb::Expand & expand,
+    const ExpressionActionsPtr & actions)
+{
+    GroupingSets group_sets_columns;
+    std::map<String, bool> map_grouping_col;
+    group_sets_columns.reserve(expand.grouping_sets().size());
+    for (const auto & group_set : expand.grouping_sets())
+    {
+        GroupingSet group_set_columns;
+        group_set_columns.reserve(group_set.grouping_exprs().size());
+        for (const auto & group_exprs : group_set.grouping_exprs())
+        {
+            GroupingColumnNames group_exprs_columns;
+            group_exprs_columns.reserve(group_exprs.grouping_expr().size());
+            for (const auto & group_expr : group_exprs.grouping_expr())
+            {
+                String cp_name = getActions(group_expr, actions);
+                // tidb expression computation is based on column index offset child's chunk schema, change to ck block column name here.
+                group_exprs_columns.emplace_back(cp_name);
+                map_grouping_col.insert(std::pair<String, bool>(cp_name, true));
+            }
+            // move here, cause basic string is copied from input cols.
+            group_set_columns.emplace_back(std::move(group_exprs_columns));
+        }
+        group_sets_columns.emplace_back(std::move(group_set_columns));
+    }
+    // change the original source column to be nullable, and add a new column for groupingID.
+    for (auto & mutable_one : source_columns)
+    {
+        if (map_grouping_col[mutable_one.name])
+            mutable_one.type = makeNullable(mutable_one.type);
+    }
+    source_columns.emplace_back(Expand::grouping_identifier_column_name, Expand::grouping_identifier_column_type);
+    return group_sets_columns;
+}
+
+ExpressionActionsPtr DAGExpressionAnalyzer::appendExpand(
+    const tipb::Expand & expand,
+    ExpressionActionsChain & chain)
+{
+    auto & last_step = initAndGetLastStep(chain);
+    for (const auto & origin_col : last_step.actions->getSampleBlock().getNamesAndTypesList())
+    {
+        last_step.required_output.push_back(origin_col.name);
+    }
+    auto grouping_sets = buildExpandGroupingColumns(expand, last_step.actions);
+    last_step.actions->add(ExpressionAction::expandSource(grouping_sets));
+
+    auto before_expand = chain.getLastActions();
+    chain.finalize();
+    chain.clear();
+
+    auto & after_expand_step = initAndGetLastStep(chain);
+    for (const auto & column : getCurrentInputColumns())
+        after_expand_step.required_output.push_back(column.name);
+    return before_expand;
+}
+
 std::vector<NameAndTypePair> DAGExpressionAnalyzer::appendOrderBy(
     ExpressionActionsChain & chain,
     const tipb::TopN & topN)

dbms/src/Flash/Coprocessor/DAGExpressionAnalyzer.h

@@ -71,6 +71,10 @@ class DAGExpressionAnalyzer : private boost::noncopyable
         ExpressionActionsChain & chain,
         const std::vector<const tipb::Expr *> & conditions);
 
+    GroupingSets buildExpandGroupingColumns(const tipb::Expand & expand, const ExpressionActionsPtr & actions);
+
+    ExpressionActionsPtr appendExpand(const tipb::Expand & expand, ExpressionActionsChain & chain);
+
     NamesAndTypes buildWindowOrderColumns(const tipb::Sort & window_sort) const;
 
     std::vector<NameAndTypePair> appendOrderBy(

dbms/src/Flash/Coprocessor/DAGQueryBlock.cpp

@@ -46,6 +46,7 @@ bool isSourceNode(const tipb::Executor * root)
 const static String SOURCE_NAME("source");
 const static String SEL_NAME("selection");
 const static String AGG_NAME("aggregation");
+const static String EXPAND_NAME("expand");
 const static String WINDOW_NAME("window");
 const static String WINDOW_SORT_NAME("window_sort");
 const static String HAVING_NAME("having");
@@ -96,6 +97,12 @@ DAGQueryBlock::DAGQueryBlock(const tipb::Executor & root_, QueryBlockIDGenerator
             }
             current = &current->selection().child();
             break;
+        case tipb::ExecType::TypeExpand:
+            GET_METRIC(tiflash_coprocessor_executor_count, type_expand).Increment();
+            assignOrThrowException(&expand, current, EXPAND_NAME);
+            expand_name = current->executor_id();
+            current = &current->expand().child();
+            break;
         case tipb::ExecType::TypeStreamAgg:
             RUNTIME_CHECK_MSG(current->aggregation().group_by_size() == 0, STREAM_AGG_ERROR);
         case tipb::ExecType::TypeAggregation:

dbms/src/Flash/Coprocessor/DAGQueryBlock.h

@@ -60,6 +60,8 @@ class DAGQueryBlock
     String having_name;
     const tipb::Executor * limit_or_topn = nullptr;
     String limit_or_topn_name;
+    const tipb::Executor * expand = nullptr;
+    String expand_name;
     const tipb::Executor * exchange_sender = nullptr;
     String exchange_sender_name;
     UInt32 id;

dbms/src/Flash/Coprocessor/DAGQueryBlockInterpreter.cpp

@@ -18,6 +18,7 @@
 #include <Core/NamesAndTypes.h>
 #include <DataStreams/AggregatingBlockInputStream.h>
 #include <DataStreams/ExchangeSenderBlockInputStream.h>
+#include <DataStreams/ExpressionBlockInputStream.h>
 #include <DataStreams/FilterBlockInputStream.h>
 #include <DataStreams/HashJoinBuildBlockInputStream.h>
 #include <DataStreams/HashJoinProbeBlockInputStream.h>
@@ -43,6 +44,7 @@
 #include <Flash/Coprocessor/StorageDisaggregatedInterpreter.h>
 #include <Flash/Mpp/newMPPExchangeWriter.h>
 #include <Interpreters/Aggregator.h>
+#include <Interpreters/Expand.h>
 #include <Interpreters/Join.h>
 #include <Parsers/ASTSelectQuery.h>
 #include <Storages/Transaction/TMTContext.h>
@@ -73,7 +75,9 @@ struct AnalysisResult
     ExpressionActionsPtr before_where;
     ExpressionActionsPtr before_aggregation;
     ExpressionActionsPtr before_having;
-    ExpressionActionsPtr before_order_and_select;
+    ExpressionActionsPtr before_order;
+    ExpressionActionsPtr before_expand;
+    ExpressionActionsPtr before_select;
     ExpressionActionsPtr final_projection;
 
     String filter_column_name;
@@ -131,6 +135,14 @@ AnalysisResult analyzeExpressions(
     if (query_block.limit_or_topn && query_block.limit_or_topn->tp() == tipb::ExecType::TypeTopN)
     {
         res.order_columns = analyzer.appendOrderBy(chain, query_block.limit_or_topn->topn());
+        res.before_order = chain.getLastActions();
+        chain.addStep();
+    }
+
+    if (query_block.expand)
+    {
+        res.before_expand = analyzer.appendExpand(query_block.expand->expand(), chain);
+        chain.addStep();
     }
 
     const auto & dag_context = *context.getDAGContext();
@@ -146,7 +158,7 @@ AnalysisResult analyzeExpressions(
             chain,
             query_block.qb_column_prefix);
 
-    res.before_order_and_select = chain.getLastActions();
+    res.before_select = chain.getLastActions();
 
     chain.finalize();
     chain.clear();
@@ -570,12 +582,12 @@ void DAGQueryBlockInterpreter::handleWindowOrder(DAGPipeline & pipeline, const t
 }
 
 // To execute a query block, you have to:
-// 1. generate the date stream and push it to pipeline.
+// 1. generate the data stream and push it to pipeline.
 // 2. assign the analyzer
 // 3. construct a final projection, even if it's not necessary. just construct it.
 // Talking about projection, it has the following rules.
 // 1. if the query block does not contain agg, then the final project is the same as the source Executor
-// 2. if the query block contains agg, then the final project is the same as agg Executor
+// 2. if the query block contains agg/expand, then the final project is the same as agg/expand Executor
 // 3. if the cop task may contains more then 1 query block, and the current query block is not the root
 //    query block, then the project should add an alias for each column that needs to be projected, something
 //    like final_project.emplace_back(col.name, query_block.qb_column_prefix + col.name);
@@ -664,9 +676,9 @@ void DAGQueryBlockInterpreter::executeImpl(DAGPipeline & pipeline)
         executeWhere(pipeline, res.before_having, res.having_column_name, "execute having");
         recordProfileStreams(pipeline, query_block.having_name);
     }
-    if (res.before_order_and_select)
+    if (res.before_order)
     {
-        executeExpression(pipeline, res.before_order_and_select, log, "before order and select");
+        executeExpression(pipeline, res.before_order, log, "before order");
     }
 
     if (!res.order_columns.empty())
@@ -676,14 +688,30 @@ void DAGQueryBlockInterpreter::executeImpl(DAGPipeline & pipeline)
         recordProfileStreams(pipeline, query_block.limit_or_topn_name);
     }
 
-    // execute final project action
-    executeProject(pipeline, final_project, "final projection");
     // execute limit
     if (query_block.limit_or_topn && query_block.limit_or_topn->tp() == tipb::TypeLimit)
     {
         executeLimit(pipeline);
         recordProfileStreams(pipeline, query_block.limit_or_topn_name);
     }
+
+    // execute the expand OP after all filter/limits and so on.
+    // since expand OP has some row replication work to do, place it after limit can reduce some unnecessary burden.
+    // and put it before the final projection, because we should recognize some base col as grouping set col before change their alias.
+    if (res.before_expand)
+    {
+        executeExpand(pipeline, res.before_expand);
+        recordProfileStreams(pipeline, query_block.expand_name);
+    }
+
+    if (res.before_select)
+    {
+        executeExpression(pipeline, res.before_select, log, "before select");
+    }
+
+    // execute final project action
+    executeProject(pipeline, final_project, "final projection");
+
     restorePipelineConcurrency(pipeline);
 
     // execute exchange_sender
@@ -724,6 +752,15 @@ void DAGQueryBlockInterpreter::executeLimit(DAGPipeline & pipeline)
     }
 }
 
+void DAGQueryBlockInterpreter::executeExpand(DAGPipeline & pipeline, const ExpressionActionsPtr & expr)
+{
+    String expand_extra_info = fmt::format("expand: grouping set {}", expr->getActions().back().expand->getGroupingSetsDes());
+    pipeline.transform([&](auto & stream) {
+        stream = std::make_shared<ExpressionBlockInputStream>(stream, expr, log->identifier());
+        stream->setExtraInfo(expand_extra_info);
+    });
+}
+
 void DAGQueryBlockInterpreter::handleExchangeSender(DAGPipeline & pipeline)
 {
     RUNTIME_ASSERT(dagContext().isMPPTask() && dagContext().tunnel_set != nullptr, log, "exchange_sender only run in MPP");