diff --git a/dbcon/mysql/ha_from_sub.cpp b/dbcon/mysql/ha_from_sub.cpp
index 442743c2d..3fc987f82 100644
--- a/dbcon/mysql/ha_from_sub.cpp
+++ b/dbcon/mysql/ha_from_sub.cpp
@@ -51,9 +51,6 @@ void derivedTableOptimization(gp_walk_info* gwip, SCSEP& csep)
   // derived tables are not checked for optimization in this scope.
   CalpontSelectExecutionPlan::SelectList derivedTbList = csep->derivedTableList();
 
-  // @bug6156. Skip horizontal optimization for no table union.
-  bool horizontalOptimization = true;
-
   for (uint i = 0; i < derivedTbList.size(); i++)
   {
     CalpontSelectExecutionPlan* plan = reinterpret_cast<CalpontSelectExecutionPlan*>(derivedTbList[i].get());
@@ -76,18 +73,6 @@ void derivedTableOptimization(gp_walk_info* gwip, SCSEP& csep)
       }
     }
 
-    if (plan->tableList().empty())
-      horizontalOptimization = false;
-
-    for (uint j = 0; j < plan->unionVec().size(); j++)
-    {
-      if (reinterpret_cast<CalpontSelectExecutionPlan*>(plan->unionVec()[j].get())->tableList().empty())
-      {
-        horizontalOptimization = false;
-        break;
-      }
-    }
-
     if (verticalOptimization)
     {
       int64_t val = 1;
@@ -203,203 +188,6 @@ void derivedTableOptimization(gp_walk_info* gwip, SCSEP& csep)
       }
     }
   }
-
-  /*
-   * @bug5635. Move filters that only belongs to a derived table to inside the derived table.
-   * 1. parse tree walk to populate derivedTableFilterMap and set null candidate on the tree.
-   * 2. remove the null filters
-   * 3. and the filters of derivedTableFilterMap and append to the WHERE filter of the derived table
-   *
-   * Note:
-   * 1. Subquery filters is ignored because derived table can not be in subquery
-   * 2. While walking tree, whenever a single derive simplefilter is encountered,
-   * this filter is pushed to the corresponding stack
-   * 2. Whenever an OR operator is encountered, all the filter stack of
-   * that OR involving derived table are emptied and null candidate of each
-   * stacked filter needs to be reset (not null)
-   */
-  ParseTree* pt = csep->filters();
-  map<string, ParseTree*> derivedTbFilterMap;
-
-  if (horizontalOptimization && pt)
-  {
-    pt->walk(setDerivedTable);
-    setDerivedFilter(gwip, pt, derivedTbFilterMap, derivedTbList);
-    csep->filters(pt);
-  }
-
-  // AND the filters of individual stack to the derived table filter tree
-  // @todo union filters.
-  // @todo outer join complication
-  map<string, ParseTree*>::iterator mapIt;
-
-  for (uint i = 0; i < derivedTbList.size(); i++)
-  {
-    CalpontSelectExecutionPlan* plan = reinterpret_cast<CalpontSelectExecutionPlan*>(derivedTbList[i].get());
-    CalpontSelectExecutionPlan::ReturnedColumnList derivedColList = plan->returnedCols();
-    mapIt = derivedTbFilterMap.find(plan->derivedTbAlias());
-
-    if (mapIt != derivedTbFilterMap.end())
-    {
-      // replace all derived column of this filter with real column from
-      // derived table projection list.
-      ParseTree* mainFilter = new ParseTree();
-      mainFilter->copyTree(*(mapIt->second));
-      replaceRefCol(mainFilter, derivedColList);
-      ParseTree* derivedFilter = plan->filters();
-
-      if (derivedFilter)
-      {
-        LogicOperator* op = new LogicOperator("and");
-        ParseTree* filter = new ParseTree(op);
-        filter->left(derivedFilter);
-        filter->right(mainFilter);
-        plan->filters(filter);
-      }
-      else
-      {
-        plan->filters(mainFilter);
-      }
-
-      // union filter handling
-      for (uint j = 0; j < plan->unionVec().size(); j++)
-      {
-        CalpontSelectExecutionPlan* unionPlan =
-            reinterpret_cast<CalpontSelectExecutionPlan*>(plan->unionVec()[j].get());
-        CalpontSelectExecutionPlan::ReturnedColumnList unionColList = unionPlan->returnedCols();
-        ParseTree* mainFilterForUnion = new ParseTree();
-        mainFilterForUnion->copyTree(*(mapIt->second));
-        replaceRefCol(mainFilterForUnion, unionColList);
-        ParseTree* unionFilter = unionPlan->filters();
-
-        if (unionFilter)
-        {
-          LogicOperator* op = new LogicOperator("and");
-          ParseTree* filter = new ParseTree(op);
-          filter->left(unionFilter);
-          filter->right(mainFilterForUnion);
-          unionPlan->filters(filter);
-        }
-        else
-        {
-          unionPlan->filters(mainFilterForUnion);
-        }
-      }
-    }
-  }
-
-  // clean derivedTbFilterMap because all the filters are copied
-  for (mapIt = derivedTbFilterMap.begin(); mapIt != derivedTbFilterMap.end(); ++mapIt)
-    delete (*mapIt).second;
-
-  // recursively process the nested derived table
-  for (uint i = 0; i < csep->subSelectList().size(); i++)
-  {
-    SCSEP subselect(boost::dynamic_pointer_cast<CalpontSelectExecutionPlan>(csep->subSelectList()[i]));
-    derivedTableOptimization(gwip, subselect);
-  }
-}
-
-void setDerivedTable(execplan::ParseTree* n)
-{
-  ParseTree* lhs = n->left();
-  ParseTree* rhs = n->right();
-
-  Operator* op = dynamic_cast<Operator*>(n->data());
-
-  // if logic operator then lhs and rhs can't be both null
-  if (op)
-  {
-    if (!lhs || lhs->derivedTable() == "*")
-    {
-      n->derivedTable(rhs ? rhs->derivedTable() : "*");
-    }
-    else if (!rhs || rhs->derivedTable() == "*")
-    {
-      n->derivedTable(lhs->derivedTable());
-    }
-    else if (lhs->derivedTable() == rhs->derivedTable())
-    {
-      n->derivedTable(lhs->derivedTable());
-    }
-    else
-    {
-      n->derivedTable("");
-    }
-  }
-  else
-  {
-    n->data()->setDerivedTable();
-    n->derivedTable(n->data()->derivedTable());
-  }
-}
-
-ParseTree* setDerivedFilter(gp_walk_info* gwip, ParseTree*& n, map<string, ParseTree*>& filterMap,
-                            CalpontSelectExecutionPlan::SelectList& derivedTbList)
-{
-  if (!(n->derivedTable().empty()))
-  {
-    // @todo replace virtual column of n to real column
-    // all simple columns should belong to the same derived table
-    CalpontSelectExecutionPlan* csep = NULL;
-
-    for (uint i = 0; i < derivedTbList.size(); i++)
-    {
-      CalpontSelectExecutionPlan* plan = dynamic_cast<CalpontSelectExecutionPlan*>(derivedTbList[i].get());
-
-      if (plan->derivedTbAlias() == n->derivedTable())
-      {
-        csep = plan;
-        break;
-      }
-    }
-
-    // should never be null; if null then give up optimization.
-    if (!csep)
-      return n;
-
-    // 2. push the filter to the derived table filter stack, or 'and' with
-    // the filters in the stack
-    map<string, ParseTree*>::iterator mapIter = filterMap.find(n->derivedTable());
-
-    if (mapIter == filterMap.end())
-    {
-      filterMap.insert(pair<string, ParseTree*>(n->derivedTable(), n));
-    }
-    else
-    {
-      ParseTree* pt = new ParseTree(new LogicOperator("and"));
-      pt->left(mapIter->second);
-      pt->right(n);
-      mapIter->second = pt;
-    }
-
-    int64_t val = 1;
-    n = new ParseTree(new ConstantColumn(val));
-    (dynamic_cast<ConstantColumn*>(n->data()))->timeZone(gwip->timeZone);
-  }
-  else
-  {
-    Operator* op = dynamic_cast<Operator*>(n->data());
-
-    if (op && (op->op() == OP_OR || op->op() == OP_XOR))
-    {
-      return n;
-    }
-    else
-    {
-      ParseTree* lhs = n->left();
-      ParseTree* rhs = n->right();
-
-      if (lhs)
-        n->left(setDerivedFilter(gwip, lhs, filterMap, derivedTbList));
-
-      if (rhs)
-        n->right(setDerivedFilter(gwip, rhs, filterMap, derivedTbList));
-    }
-  }
-
-  return n;
 }
 
 FromSubQuery::FromSubQuery(gp_walk_info& gwip) : SubQuery(gwip)
diff --git a/dbcon/mysql/ha_mcs_execplan.cpp b/dbcon/mysql/ha_mcs_execplan.cpp
index 7618dd180..893df3fd9 100644
--- a/dbcon/mysql/ha_mcs_execplan.cpp
+++ b/dbcon/mysql/ha_mcs_execplan.cpp
@@ -7474,12 +7474,11 @@ int cs_get_select_plan(ha_columnstore_select_handler* handler, THD* thd, SCSEP&
     cerr << "-------------- EXECUTION PLAN END --------------\n" << endl;
   }
 
-  // Derived table projection and filter optimization.
+  // Derived table projection list optimization.
   derivedTableOptimization(&gwi, csep);
 
-  if (get_unstable_optimizer(thd))
   {
-    optimizer::RBOptimizerContext ctx(gwi);
+    optimizer::RBOptimizerContext ctx(gwi, *thd);
     bool csepWasOptimized = optimizer::optimizeCSEP(*csep, ctx);
     if (csep->traceOn() && csepWasOptimized)
     {
diff --git a/dbcon/mysql/rbo_predicate_pushdown.cpp b/dbcon/mysql/rbo_predicate_pushdown.cpp
new file mode 100644
index 000000000..83bd005b7
--- /dev/null
+++ b/dbcon/mysql/rbo_predicate_pushdown.cpp
@@ -0,0 +1,236 @@
+/* Copyright (C) 2025 MariaDB Corporation
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License
+   as published by the Free Software Foundation; version 2 of
+   the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+   MA 02110-1301, USA. */
+
+#include <cstddef>
+#include <cstdint>
+
+#include "rulebased_optimizer.h"
+
+#include "constantcolumn.h"
+#include "execplan/calpontselectexecutionplan.h"
+#include "execplan/simplecolumn.h"
+#include "logicoperator.h"
+#include "operator.h"
+
+namespace optimizer
+{
+
+bool matchPredicatePushdown(execplan::CalpontSelectExecutionPlan& csep)
+{
+  // The original rule match contains questionable decision to filter out
+  // queries that contains any UNION UNIT with only derived tables.
+  // See ha_from_sub.cpp before MCS 23.10.7 for more details and @bug6156.
+  // All tables are derived thus nothing to optimize.
+  return !csep.tableList().empty();
+}
+
+
+void setDerivedTable(execplan::ParseTree* n)
+{
+  execplan::ParseTree* lhs = n->left();
+  execplan::ParseTree* rhs = n->right();
+
+  execplan::Operator* op = dynamic_cast<execplan::Operator*>(n->data());
+
+  // if logic operator then lhs and rhs can't be both null
+  if (op)
+  {
+    if (!lhs || lhs->derivedTable() == "*")
+    {
+      n->derivedTable(rhs ? rhs->derivedTable() : "*");
+    }
+    else if (!rhs || rhs->derivedTable() == "*")
+    {
+      n->derivedTable(lhs->derivedTable());
+    }
+    else if (lhs->derivedTable() == rhs->derivedTable())
+    {
+      n->derivedTable(lhs->derivedTable());
+    }
+    else
+    {
+      n->derivedTable("");
+    }
+  }
+  else
+  {
+    n->data()->setDerivedTable();
+    n->derivedTable(n->data()->derivedTable());
+  }
+}
+
+execplan::ParseTree* setDerivedFilter(cal_impl_if::gp_walk_info* gwip, execplan::ParseTree*& n, map<string, execplan::ParseTree*>& filterMap,
+                            const execplan::CalpontSelectExecutionPlan::SelectList& derivedTbList)
+{
+  if (!(n->derivedTable().empty()))
+  {
+    // @todo replace virtual column of n to real column
+    // all simple columns should belong to the same derived table
+    execplan::CalpontSelectExecutionPlan* csep = NULL;
+
+    for (uint i = 0; i < derivedTbList.size(); i++)
+    {
+      execplan::CalpontSelectExecutionPlan* plan = dynamic_cast<execplan::CalpontSelectExecutionPlan*>(derivedTbList[i].get());
+
+      if (plan->derivedTbAlias() == n->derivedTable())
+      {
+        csep = plan;
+        break;
+      }
+    }
+
+    // should never be null; if null then give up optimization.
+    if (!csep)
+      return n;
+
+    // 2. push the filter to the derived table filter stack, or 'and' with
+    // the filters in the stack
+    map<string, execplan::ParseTree*>::iterator mapIter = filterMap.find(n->derivedTable());
+
+    if (mapIter == filterMap.end())
+    {
+      filterMap.insert(pair<string, execplan::ParseTree*>(n->derivedTable(), n));
+    }
+    else
+    {
+      execplan::ParseTree* pt = new execplan::ParseTree(new execplan::LogicOperator("and"));
+      pt->left(mapIter->second);
+      pt->right(n);
+      mapIter->second = pt;
+    }
+
+    int64_t val = 1;
+    n = new execplan::ParseTree(new execplan::ConstantColumn(val));
+    (dynamic_cast<execplan::ConstantColumn*>(n->data()))->timeZone(gwip->timeZone);
+  }
+  else
+  {
+    execplan::Operator* op = dynamic_cast<execplan::Operator*>(n->data());
+
+    if (op && (op->op() == execplan::OP_OR || op->op() == execplan::OP_XOR))
+    {
+      return n;
+    }
+    else
+    {
+      execplan::ParseTree* lhs = n->left();
+      execplan::ParseTree* rhs = n->right();
+
+      if (lhs)
+        n->left(optimizer::setDerivedFilter(gwip, lhs, filterMap, derivedTbList));
+
+      if (rhs)
+        n->right(optimizer::setDerivedFilter(gwip, rhs, filterMap, derivedTbList));
+    }
+  }
+
+  return n;
+}
+
+void applyPredicatePushdown(execplan::CalpontSelectExecutionPlan& csep, RBOptimizerContext& ctx)
+{
+  /*
+   * @bug5635. Move filters that only belongs to a derived table to inside the derived table.
+   * 1. parse tree walk to populate derivedTableFilterMap and set null candidate on the tree.
+   * 2. remove the null filters
+   * 3. and the filters of derivedTableFilterMap and append to the WHERE filter of the derived table
+   *
+   * Note:
+   * 1. Subquery filters is ignored because derived table can not be in subquery
+   * 2. While walking tree, whenever a single derive simplefilter is encountered,
+   * this filter is pushed to the corresponding stack
+   * 2. Whenever an OR operator is encountered, all the filter stack of
+   * that OR involving derived table are emptied and null candidate of each
+   * stacked filter needs to be reset (not null)
+   */
+   execplan::ParseTree* pt = csep.filters();
+   map<string, execplan::ParseTree*> derivedTbFilterMap;
+   auto& derivedTbList = csep.derivedTableList();
+
+   if (pt)
+   {
+     pt->walk(setDerivedTable);
+     setDerivedFilter(&ctx.gwi, pt, derivedTbFilterMap, derivedTbList);
+     csep.filters(pt);
+   }
+ 
+   // AND the filters of individual stack to the derived table filter tree
+   // @todo union filters.
+   // @todo outer join complication
+   map<string, execplan::ParseTree*>::iterator mapIt;
+ 
+   for (uint i = 0; i < derivedTbList.size(); i++)
+   {
+     execplan::CalpontSelectExecutionPlan* plan = dynamic_cast<execplan::CalpontSelectExecutionPlan*>(derivedTbList[i].get());
+     execplan::CalpontSelectExecutionPlan::ReturnedColumnList derivedColList = plan->returnedCols();
+     mapIt = derivedTbFilterMap.find(plan->derivedTbAlias());
+ 
+     if (mapIt != derivedTbFilterMap.end())
+     {
+       // replace all derived column of this filter with real column from
+       // derived table projection list.
+       execplan::ParseTree* mainFilter = new execplan::ParseTree();
+       mainFilter->copyTree(*(mapIt->second));
+       replaceRefCol(mainFilter, derivedColList);
+       execplan::ParseTree* derivedFilter = plan->filters();
+ 
+       if (derivedFilter)
+       {
+         execplan::LogicOperator* op = new execplan::LogicOperator("and");
+         execplan::ParseTree* filter = new execplan::ParseTree(op);
+         filter->left(derivedFilter);
+         filter->right(mainFilter);
+         plan->filters(filter);
+       }
+       else
+       {
+         plan->filters(mainFilter);
+       }
+ 
+       // union filter handling
+       for (uint j = 0; j < plan->unionVec().size(); j++)
+       {
+         execplan::CalpontSelectExecutionPlan* unionPlan =
+             reinterpret_cast<execplan::CalpontSelectExecutionPlan*>(plan->unionVec()[j].get());
+         execplan::CalpontSelectExecutionPlan::ReturnedColumnList unionColList = unionPlan->returnedCols();
+         execplan::ParseTree* mainFilterForUnion = new execplan::ParseTree();
+         mainFilterForUnion->copyTree(*(mapIt->second));
+         replaceRefCol(mainFilterForUnion, unionColList);
+         execplan::ParseTree* unionFilter = unionPlan->filters();
+ 
+         if (unionFilter)
+         {
+           execplan::LogicOperator* op = new execplan::LogicOperator("and");
+           execplan::ParseTree* filter = new execplan::ParseTree(op);
+           filter->left(unionFilter);
+           filter->right(mainFilterForUnion);
+           unionPlan->filters(filter);
+         }
+         else
+         {
+           unionPlan->filters(mainFilterForUnion);
+         }
+       }
+     }
+   }
+ 
+   // clean derivedTbFilterMap because all the filters are copied
+   for (mapIt = derivedTbFilterMap.begin(); mapIt != derivedTbFilterMap.end(); ++mapIt)
+     delete (*mapIt).second;
+}
+
+}  // namespace optimizer
diff --git a/dbcon/mysql/rbo_predicate_pushdown.h b/dbcon/mysql/rbo_predicate_pushdown.h
new file mode 100644
index 000000000..31967f0be
--- /dev/null
+++ b/dbcon/mysql/rbo_predicate_pushdown.h
@@ -0,0 +1,30 @@
+/* Copyright (C) 2025 MariaDB Corporation
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License
+   as published by the Free Software Foundation; version 2 of
+   the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+   MA 02110-1301, USA. */
+
+#pragma once
+
+#define PREFER_MY_CONFIG_H
+#include <my_config.h>
+#include "idb_mysql.h"
+
+#include "execplan/calpontselectexecutionplan.h"
+#include "rulebased_optimizer.h"
+
+namespace optimizer {
+  bool matchPredicatePushdown(execplan::CalpontSelectExecutionPlan& csep);
+  void applyPredicatePushdown(execplan::CalpontSelectExecutionPlan& csep, optimizer::RBOptimizerContext& ctx);
+}
\ No newline at end of file
diff --git a/dbcon/mysql/rulebased_optimizer.cpp b/dbcon/mysql/rulebased_optimizer.cpp
index f01f79321..a572d4ce5 100644
--- a/dbcon/mysql/rulebased_optimizer.cpp
+++ b/dbcon/mysql/rulebased_optimizer.cpp
@@ -50,9 +50,17 @@ bool optimizeCSEPWithRules(execplan::CalpontSelectExecutionPlan& root, const std
 // high level API call for optimizer
 bool optimizeCSEP(execplan::CalpontSelectExecutionPlan& root, optimizer::RBOptimizerContext& ctx)
 {
-  optimizer::Rule parallelCES{"parallelCES", optimizer::matchParallelCES, optimizer::applyParallelCES};
+  std::vector<optimizer::Rule> rules;
 
-  std::vector<optimizer::Rule> rules = {parallelCES};
+  if (get_unstable_optimizer(&ctx.thd))
+  {
+    optimizer::Rule parallelCES{"parallelCES", optimizer::matchParallelCES, optimizer::applyParallelCES};
+    rules.push_back(parallelCES);
+  }
+
+  optimizer::Rule predicatePushdown{"predicatePushdown", optimizer::matchParallelCES,
+                                    optimizer::applyParallelCES};
+  rules.push_back(predicatePushdown);
 
   return optimizeCSEPWithRules(root, rules, ctx);
 }
@@ -85,6 +93,7 @@ bool Rule::walk(execplan::CalpontSelectExecutionPlan& csep, optimizer::RBOptimiz
     execplan::CalpontSelectExecutionPlan* current = planStack.top();
     planStack.pop();
 
+    // Walk nested derived
     for (auto& table : current->derivedTableList())
     {
       auto* csepPtr = dynamic_cast<execplan::CalpontSelectExecutionPlan*>(table.get());
@@ -94,6 +103,7 @@ bool Rule::walk(execplan::CalpontSelectExecutionPlan& csep, optimizer::RBOptimiz
       }
     }
 
+    // Walk nested UNION UNITS
     for (auto& unionUnit : current->unionVec())
     {
       auto* unionUnitPtr = dynamic_cast<execplan::CalpontSelectExecutionPlan*>(unionUnit.get());
@@ -103,6 +113,18 @@ bool Rule::walk(execplan::CalpontSelectExecutionPlan& csep, optimizer::RBOptimiz
       }
     }
 
+    // Walk nested subselect in filters, e.g. SEMI-JOIN
+    for (auto& subselect : csep.subSelectList())
+    {
+      auto* subselectPtr = dynamic_cast<execplan::CalpontSelectExecutionPlan*>(subselect.get());
+      if (subselectPtr)
+      {
+        planStack.push(subselectPtr);
+      }
+    }
+
+    // TODO add walking nested subselect in projection. See CSEP::fSelectSubList
+
     if (matchRule(*current))
     {
       applyRule(*current, ctx);
diff --git a/dbcon/mysql/rulebased_optimizer.h b/dbcon/mysql/rulebased_optimizer.h
index c047a406e..515d420c9 100644
--- a/dbcon/mysql/rulebased_optimizer.h
+++ b/dbcon/mysql/rulebased_optimizer.h
@@ -32,10 +32,11 @@ namespace optimizer {
 class RBOptimizerContext {
 public:
   RBOptimizerContext() = delete;
-  RBOptimizerContext(cal_impl_if::gp_walk_info& walk_info) : gwi(walk_info) {}
+  RBOptimizerContext(cal_impl_if::gp_walk_info& walk_info, THD& thd) : gwi(walk_info), thd(thd) {}
   // gwi lifetime should be longer than optimizer context. 
   // In plugin runtime this is always true.
   cal_impl_if::gp_walk_info& gwi;
+  THD& thd;
   uint64_t uniqueId {0};
 };