From 2a18c649f0db28ca5348fbd43ba078a0d0b0c89d Mon Sep 17 00:00:00 2001
From: zclllyybb <zhaochangle@selectdb.com>
Date: Thu, 30 May 2024 13:59:40 +0800
Subject: [PATCH] [FE](session-variable) Add a debug variable of constant fold
 (#35584)

which force skip constant fold in nereids. make it easier for test,
especially for SqlLogic platform
---
 .../expression/rules/FoldConstantRuleOnBE.java      |  5 ++++-
 .../java/org/apache/doris/qe/SessionVariable.java   | 13 +++++++++++++
 .../main/java/org/apache/doris/qe/StmtExecutor.java |  3 ++-
 3 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/expression/rules/FoldConstantRuleOnBE.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/expression/rules/FoldConstantRuleOnBE.java
index 1739c147d8678d0..ba14487daf90eee 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/expression/rules/FoldConstantRuleOnBE.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/expression/rules/FoldConstantRuleOnBE.java
@@ -72,7 +72,10 @@ public class FoldConstantRuleOnBE extends AbstractExpressionRewriteRule {
 
     @Override
     public Expression rewrite(Expression expr, ExpressionRewriteContext ctx) {
-        Expression expression = FoldConstantRuleOnFE.INSTANCE.rewrite(expr, ctx);
+        if(ctx.cascadesContext.getConnectContext().getSessionVariable().isDebugSkipFoldConstant()) {
+		    return null;
+		}
+	    Expression expression = FoldConstantRuleOnFE.INSTANCE.rewrite(expr, ctx);
         return foldByBE(expression, ctx);
     }
 
diff --git a/fe/fe-core/src/main/java/org/apache/doris/qe/SessionVariable.java b/fe/fe-core/src/main/java/org/apache/doris/qe/SessionVariable.java
index 8a5c3a85055b88a..9879986438aedd1 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/qe/SessionVariable.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/qe/SessionVariable.java
@@ -121,6 +121,8 @@ public class SessionVariable implements Serializable, Writable {
     public static final String PREFER_JOIN_METHOD = "prefer_join_method";
 
     public static final String ENABLE_FOLD_CONSTANT_BY_BE = "enable_fold_constant_by_be";
+    public static final String DEBUG_SKIP_FOLD_CONSTANT = "debug_skip_fold_constant";
+
     public static final String ENABLE_ODBC_TRANSCATION = "enable_odbc_transcation";
     public static final String ENABLE_SQL_CACHE = "enable_sql_cache";
     public static final String ENABLE_PARTITION_CACHE = "enable_partition_cache";
@@ -807,6 +809,9 @@ public class SessionVariable implements Serializable, Writable {
     @VariableMgr.VarAttr(name = ENABLE_FOLD_CONSTANT_BY_BE, fuzzy = true)
     private boolean enableFoldConstantByBe = false;
 
+    @VariableMgr.VarAttr(name = DEBUG_SKIP_FOLD_CONSTANT)
+    public boolean debugSkipFoldConstant = false;
+
     @VariableMgr.VarAttr(name = RUNTIME_FILTER_MODE, needForward = true)
     private String runtimeFilterMode = "GLOBAL";
 
@@ -1933,6 +1938,10 @@ public boolean isEnableFoldConstantByBe() {
         return enableFoldConstantByBe;
     }
 
+    public boolean isDebugSkipFoldConstant() {
+        return debugSkipFoldConstant;
+    }
+
     public boolean isEnableNereidsDML() {
         return enableNereidsDML;
     }
@@ -1941,6 +1950,10 @@ public void setEnableFoldConstantByBe(boolean foldConstantByBe) {
         this.enableFoldConstantByBe = foldConstantByBe;
     }
 
+    public void setDebugSkipFoldConstant(boolean debugSkipFoldConstant) {
+        this.debugSkipFoldConstant = debugSkipFoldConstant;
+    }
+
     public int getParallelExecInstanceNum() {
         ConnectContext connectContext = ConnectContext.get();
         if (connectContext != null && connectContext.getEnv() != null && connectContext.getEnv().getAuth() != null) {
diff --git a/fe/fe-core/src/main/java/org/apache/doris/qe/StmtExecutor.java b/fe/fe-core/src/main/java/org/apache/doris/qe/StmtExecutor.java
index 02b0872fe6b4dc9..f9131ce1b450564 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/qe/StmtExecutor.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/qe/StmtExecutor.java
@@ -1221,7 +1221,8 @@ private void analyzeAndGenerateQueryPlan(TQueryOptions tQueryOptions) throws Use
         if (parsedStmt instanceof QueryStmt || parsedStmt instanceof InsertStmt) {
             ExprRewriter rewriter = analyzer.getExprRewriter();
             rewriter.reset();
-            if (context.getSessionVariable().isEnableFoldConstantByBe()) {
+            if (context.getSessionVariable().isEnableFoldConstantByBe()
+                    && !context.getSessionVariable().isDebugSkipFoldConstant()) {
                 // fold constant expr
                 parsedStmt.foldConstant(rewriter, tQueryOptions);