Add an optimization that removes redundant equality

checks on boolean functions. This fixes a bug in
which the primary index is not used for queries like
SELECT * FROM <table> WHERE <pk> in (<n>) = 1

src/Analyzer/Passes/LogicalExpressionOptimizerPass.cpp

@@ -19,6 +19,19 @@ namespace ErrorCodes
     extern const int LOGICAL_ERROR;
 }
 
+using namespace std::literals;
+static constexpr std::array boolean_functions{
+    "equals"sv,   "notEquals"sv,   "less"sv,   "greaterOrEquals"sv, "greater"sv,      "lessOrEquals"sv,    "in"sv,     "notIn"sv,
+    "globalIn"sv, "globalNotIn"sv, "nullIn"sv, "notNullIn"sv,       "globalNullIn"sv, "globalNullNotIn"sv, "isNull"sv, "isNotNull"sv,
+    "like"sv,     "notLike"sv,     "ilike"sv,  "notILike"sv,        "empty"sv,        "notEmpty"sv,        "not"sv,    "and"sv,
+    "or"sv};
+
+static bool isBooleanFunction(const String & func_name)
+{
+    return std::any_of(
+        boolean_functions.begin(), boolean_functions.end(), [&](const auto boolean_func) { return func_name == boolean_func; });
+}
+
 /// Visitor that optimizes logical expressions _only_ in JOIN ON section
 class JoinOnLogicalExpressionOptimizerVisitor : public InDepthQueryTreeVisitorWithContext<JoinOnLogicalExpressionOptimizerVisitor>
 {
@@ -253,6 +266,12 @@ public:
             tryOptimizeAndEqualsNotEqualsChain(node);
             return;
         }
+
+        if (function_node->getFunctionName() == "equals")
+        {
+            tryOptimizeOutRedundantEquals(node);
+            return;
+        }
     }
 
 private:
@@ -552,6 +571,63 @@ private:
         function_node.getArguments().getNodes() = std::move(or_operands);
         function_node.resolveAsFunction(or_function_resolver);
     }
+
+    void tryOptimizeOutRedundantEquals(QueryTreeNodePtr & node)
+    {
+        auto & function_node = node->as<FunctionNode &>();
+        assert(function_node.getFunctionName() == "equals");
+
+        bool lhs_const;
+        bool maybe_invert;
+
+        const ConstantNode * constant;
+        const FunctionNode * child_function;
+
+        const auto function_arguments = function_node.getArguments().getNodes();
+        if (function_arguments.size() != 2)
+            return;
+
+        const auto & lhs = function_arguments[0];
+        const auto & rhs = function_arguments[1];
+
+        if ((constant = lhs->as<ConstantNode>()))
+            lhs_const = true;
+        else if ((constant = rhs->as<ConstantNode>()))
+            lhs_const = false;
+        else
+            return;
+
+        UInt64 val;
+        if (!constant->getValue().tryGet<UInt64>(val))
+            return;
+
+        if (val == 1)
+            maybe_invert = false;
+        else if (val == 0)
+            maybe_invert = true;
+        else
+            return;
+
+        if (lhs_const)
+            child_function = rhs->as<FunctionNode>();
+        else
+            child_function = lhs->as<FunctionNode>();
+
+        if (!child_function || !isBooleanFunction(child_function->getFunctionName()))
+            return;
+        if (maybe_invert)
+        {
+            auto not_resolver = FunctionFactory::instance().get("not", getContext());
+            const auto not_node = std::make_shared<FunctionNode>("not");
+            auto & arguments = not_node->getArguments().getNodes();
+            arguments.reserve(1);
+            arguments.push_back(lhs_const ? rhs : lhs);
+            not_node->resolveAsFunction(not_resolver->build(not_node->getArgumentColumns()));
+            node = not_node;
+        }
+        else
+            node = lhs_const ? rhs : lhs;
+    }
 };
 
 void LogicalExpressionOptimizerPass::run(QueryTreeNodePtr & query_tree_node, ContextPtr context)

src/Analyzer/Passes/LogicalExpressionOptimizerPass.h

@@ -96,6 +96,18 @@ namespace DB
  *
  * SELECT * FROM t1 JOIN t2 ON a <=> b
  * -------------------------------
+ *
+ * 7. Remove redundant equality checks on boolean functions.
+ *  - these requndant checks cause the primary index to not be used when if the query involves any primary key columns  
+ * -------------------------------
+ * SELECT * FROM t1 WHERE a IN (n) = 1 
+ * SELECT * FROM t1 WHERE a IN (n) = 0
+ * 
+ * will be transformed into 
+ * 
+ * SELECT * FROM t1 WHERE a IN (n) 
+ * SELECT * FROM t1 WHERE NOT a IN (n) 
+ * -------------------------------
  */
 
 class LogicalExpressionOptimizerPass final : public IQueryTreePass

tests/queries/0_stateless/03032_redundant_equals.reference

@@ -0,0 +1,23 @@
+100
+100
+100
+100
+100
+100
+0
+0
+0
+1
+100
+101
+100
+101
+100
+101
+100
+1
+1
+1
+1
+1
+1

tests/queries/0_stateless/03032_redundant_equals.sql

@@ -0,0 +1,83 @@
+DROP TABLE IF EXISTS test_table;
+
+CREATE TABLE test_table
+(
+    k UInt64,
+)
+ENGINE = MergeTree
+ORDER BY k;
+
+INSERT INTO test_table SELECT number FROM numbers(10000000);
+
+SELECT * FROM test_table WHERE k in (100) = 1;
+SELECT * FROM test_table WHERE k = (100) = 1;
+SELECT * FROM test_table WHERE k not in (100) = 0;
+SELECT * FROM test_table WHERE k != (100) = 0;
+SELECT * FROM test_table WHERE 1 = (k = 100);
+SELECT * FROM test_table WHERE 0 = (k not in (100));
+SELECT * FROM test_table WHERE k < 1 = 1;
+SELECT * FROM test_table WHERE k >= 1 = 0;
+SELECT * FROM test_table WHERE k > 1 = 0;
+SELECT * FROM test_table WHERE ((k not in (101) = 0) OR (k in (100) = 1)) = 1;
+SELECT * FROM test_table WHERE (NOT ((k not in (100) = 0) OR (k in (100) = 1))) = 0;
+SELECT * FROM test_table WHERE (NOT ((k in (101) = 0) OR (k in (100) = 1))) = 1;
+SELECT * FROM test_table WHERE ((k not in (101) = 0) OR (k in (100) = 1)) = 1;
+SELECT * FROM test_table WHERE ((k not in (99) = 1) AND (k in (100) = 1)) = 1;
+
+SELECT count()
+FROM
+(
+    EXPLAIN PLAN indexes=1
+    SELECT * FROM test_table WHERE k in (100) = 1
+)
+WHERE
+    explain LIKE '%Granules: 1/%';
+
+SELECT count()
+FROM
+(
+    EXPLAIN PLAN indexes=1
+    SELECT * FROM test_table WHERE k >= 1 = 0
+)
+WHERE
+    explain LIKE '%Granules: 1/%';
+
+SELECT count()
+FROM
+(
+    EXPLAIN PLAN indexes=1
+    SELECT * FROM test_table WHERE k not in (100) = 0
+)
+WHERE
+    explain LIKE '%Granules: 1/%';
+
+SELECT count()
+FROM
+(
+    EXPLAIN PLAN indexes=1
+    SELECT * FROM test_table WHERE k > 1 = 0
+)
+WHERE
+    explain LIKE '%Granules: 1/%';
+
+SELECT count()
+FROM
+(
+    EXPLAIN PLAN indexes=1
+    SELECT * FROM test_table WHERE (NOT ((k not in (100) = 0) OR (k in (100) = 1))) = 0
+)
+WHERE
+    explain LIKE '%Granules: 1/%';
+
+
+SELECT count()
+FROM
+(
+    EXPLAIN PLAN indexes=1
+    SELECT * FROM test_table WHERE (NOT ((k in (101) = 0) OR (k in (100) = 1))) = 1
+)
+WHERE
+    explain LIKE '%Granules: 1/%';
+
+
+DROP TABLE test_table;