diff --git a/Makefile b/Makefile
index 1707240..4564f5e 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 OS_SUPPORT = 
 MonetDB_LIB = 
 MonetDB_INC = 
-Threading = 
+Defines = 
 CXXFLAGS = --std=c++1z
 ifeq ($(AQ_DEBUG), 1)
 	OPTFLAGS = -g3 -fsanitize=address -fsanitize=leak
@@ -80,16 +80,19 @@ endif
 ifeq ($(THREADING),1)
 	LIBAQ_SRC += server/threading.cpp
 	LIBAQ_OBJ += threading.o
-	Threading +=  -DTHREADING
+	Defines +=  -DTHREADING
 endif
 
+ifeq ($(AQUERY_ITC_USE_SHMEM), 1)
+	Defines += -D__AQUERY_ITC_USE_SHMEM__
+endif
 SHAREDFLAGS += $(FPIC)
 
 info:
 	$(info $(OPTFLAGS))
 	$(info $(OS_SUPPORT))
 	$(info $(OS)) 
-	$(info $(Threading))
+	$(info $(Defines))
 	$(info "test")
 	$(info $(LIBTOOL))
 	$(info $(MonetDB_INC))
@@ -97,26 +100,26 @@ info:
 	$(info $(CXX))
 	$(info $(FPIC))
 pch:
-	$(CXX) -x c++-header server/pch.hpp $(FPIC) $(MonetDB_INC) $(OPTFLAGS) $(CXXFLAGS) $(Threading)
+	$(CXX) -x c++-header server/pch.hpp $(FPIC) $(MonetDB_INC) $(OPTFLAGS) $(CXXFLAGS) $(Defines)
 libaquery.a:
-	$(CXX) -c $(FPIC) $(PCHFLAGS) $(LIBAQ_SRC) $(MonetDB_INC) $(MonetDB_LIB) $(OS_SUPPORT) $(Threading) $(OPTFLAGS) $(LINKFLAGS) $(CXXFLAGS) &&\
+	$(CXX) -c $(FPIC) $(PCHFLAGS) $(LIBAQ_SRC) $(MonetDB_INC) $(MonetDB_LIB) $(OS_SUPPORT) $(Defines) $(OPTFLAGS) $(LINKFLAGS) $(CXXFLAGS) &&\
 	$(LIBTOOL) libaquery.a $(LIBAQ_OBJ) &&\
 	$(RANLIB) libaquery.a
 
 server.bin:
-	$(CXX) $(LIBAQ_SRC) $(LINKFLAGS) $(OS_SUPPORT) $(Threading)  $(MonetDB_INC) $(MonetDB_LIB) $(OPTFLAGS) $(CXXFLAGS) -o server.bin
+	$(CXX) $(LIBAQ_SRC) $(LINKFLAGS) $(OS_SUPPORT) $(Defines)  $(MonetDB_INC) $(MonetDB_LIB) $(OPTFLAGS) $(CXXFLAGS) -o server.bin
 launcher:
-	$(CXX) -D__AQ_BUILD_LAUNCHER__ $(LIBAQ_SRC) $(LINKFLAGS) $(OS_SUPPORT) $(Threading)  $(MonetDB_INC) $(MonetDB_LIB) $(OPTFLAGS) $(CXXFLAGS) -o aq
+	$(CXX) -D__AQ_BUILD_LAUNCHER__ $(LIBAQ_SRC) $(LINKFLAGS) $(OS_SUPPORT) $(Defines)  $(MonetDB_INC) $(MonetDB_LIB) $(OPTFLAGS) $(CXXFLAGS) -o aq
 server.so:
 #	$(CXX) -z muldefs server/server.cpp server/monetdb_conn.cpp -fPIC -shared $(OS_SUPPORT) monetdb/msvc/monetdbe.dll --std=c++1z -O3 -march=native -o server.so -I./monetdb/msvc 
-	$(CXX) $(SHAREDFLAGS) $(PCHFLAGS) $(LIBAQ_SRC) $(OS_SUPPORT) $(Threading) $(MonetDB_INC) $(MonetDB_LIB) $(OPTFLAGS) $(LINKFLAGS) $(CXXFLAGS) -o server.so 
+	$(CXX) $(SHAREDFLAGS) $(PCHFLAGS) $(LIBAQ_SRC) $(OS_SUPPORT) $(Defines) $(MonetDB_INC) $(MonetDB_LIB) $(OPTFLAGS) $(LINKFLAGS) $(CXXFLAGS) -o server.so 
 server_uselib:
 	$(CXX) $(SHAREDFLAGS) $(USELIB_FLAG),libaquery.a $(MonetDB_LIB) $(OPTFLAGS) $(LINKFLAGS) $(CXXFLAGS) -o server.so
 
 snippet:
-	$(CXX) $(SHAREDFLAGS) $(PCHFLAGS) out.cpp $(LIBAQ_SRC) $(MonetDB_INC) $(MonetDB_LIB) $(Threading) $(OPTFLAGS) $(LINKFLAGS) $(CXXFLAGS) -o dll.so
+	$(CXX) $(SHAREDFLAGS) $(PCHFLAGS) out.cpp $(LIBAQ_SRC) $(MonetDB_INC) $(MonetDB_LIB) $(Defines) $(OPTFLAGS) $(LINKFLAGS) $(CXXFLAGS) -o dll.so
 snippet_uselib:
-	$(CXX) $(SHAREDFLAGS) $(PCHFLAGS) out.cpp libaquery.a $(MonetDB_INC) $(Threading) $(MonetDB_LIB) $(OPTFLAGS) $(LINKFLAGS) $(CXXFLAGS) -o dll.so
+	$(CXX) $(SHAREDFLAGS) $(PCHFLAGS) out.cpp libaquery.a $(MonetDB_INC) $(Defines) $(MonetDB_LIB) $(OPTFLAGS) $(LINKFLAGS) $(CXXFLAGS) -o dll.so
 
 docker:
 	docker build -t aquery .
diff --git a/README.md b/README.md
index fc06b4f..1de828d 100644
--- a/README.md
+++ b/README.md
@@ -225,6 +225,7 @@ DROP TABLE my_table IF EXISTS
 
 ## Built-in functions: 
 - `avg[s]`: average of a column. `avgs(col), avgs(w, col)` is rolling and moving average with window `w` of the column `col`.
+- `var[s]`, `stddev[s]`: [moving/rolling] **population** variance, standard deviation.
 - `sum[s]`, `max[s]`, `min[s]`: similar to `avg[s]`
 - `ratios(w = 1, col)`: moving ratio of a column, e.g. `ratios(w, col)[i]=col[i-w]/col[i]`. Window `w` has default value of 1.  
 - `next(col), prev(col)`: moving column back and forth by 1, e.g. `next(col)[i] = col[i+1]`.
diff --git a/aquery_config.py b/aquery_config.py
index 2d5939b..e3600f9 100644
--- a/aquery_config.py
+++ b/aquery_config.py
@@ -2,7 +2,7 @@
 
 ## GLOBAL CONFIGURATION FLAGS
 
-version_string = '0.5.0a'
+version_string = '0.5.1a'
 add_path_to_ldpath = True
 rebuild_backend = False
 run_backend = True
@@ -21,7 +21,8 @@ def init_config():
     import os
     from engine.utils import add_dll_dir
     # os.environ['CXX'] = 'C:/Program Files/LLVM/bin/clang.exe'
-    # os.environ['THREADING'] = '1'
+    os.environ['THREADING'] = '1'
+    os.environ['AQUERY_ITC_USE_SHMEM'] = '1'
 
     if  ('__config_initialized__' not in globals() or 
             not __config_initialized__):
diff --git a/data/test.csv b/data/test.csv
index 5eb9e8f..b4fe244 100644
--- a/data/test.csv
+++ b/data/test.csv
@@ -1,11 +1,21 @@
 a, b, c, d
 1,1,2,2
+2,1,2,2
+2,4,3,4
 1,2,2,2
 1,2,3,4
 4,2,1,4
-2,1,3,4
+2,1,3,3
+2,1,1,2
 1,2,3,4
+3,2,4,2
 1,2,3,3
 3,2,1,2
-2,1,2,2
+2,1,4,2
+3,3,4,4
+2,2,3,1
+2,3,4,4
+2,4,1,2
+3,4,1,2
+2,3,2,2
 1,2,3,1
diff --git a/datagen.cpp b/datagen.cpp
index 88f5a48..c96b480 100644
--- a/datagen.cpp
+++ b/datagen.cpp
@@ -151,5 +151,5 @@ int gen_stock_data(int argc, char* argv[]){
 }
 
 int main(int argc, char* argv[]){
-    gen_stock_data(argc, argv);
+    return gen_stock_data(argc, argv);
 }
diff --git a/engine/types.py b/engine/types.py
index 3e217a3..5baf47f 100644
--- a/engine/types.py
+++ b/engine/types.py
@@ -324,10 +324,14 @@ fnfirst = OperatorBase('first', 1, as_is, cname = 'frist', sqlname = 'FRIST', ca
 #fnavg = OperatorBase('avg', 1, fp(ext(auto_extension)), cname = 'avg', sqlname = 'AVG', call = fn_behavior)
 fnsum = OperatorBase('sum', 1, long_return, cname = 'sum', sqlname = 'SUM', call = fn_behavior)
 fnavg = OperatorBase('avg', 1, lfp_return, cname = 'avg', sqlname = 'AVG', call = fn_behavior)
+fnvar = OperatorBase('var', 1, lfp_return, cname = 'var', sqlname = 'VAR_POP', call = fn_behavior)
+fnstd = OperatorBase('stddev', 1, lfp_return, cname = 'stddev', sqlname = 'STDDEV_POP', call = fn_behavior)
 fnmaxs = OperatorBase('maxs', [1, 2], ty_clamp(as_is, -1), cname = 'maxs', sqlname = 'MAXS', call = windowed_fn_behavor)
 fnmins = OperatorBase('mins', [1, 2], ty_clamp(as_is, -1), cname = 'mins', sqlname = 'MINS', call = windowed_fn_behavor)
 fnsums = OperatorBase('sums', [1, 2], ext(ty_clamp(auto_extension, -1)), cname = 'sums', sqlname = 'SUMS', call = windowed_fn_behavor)
 fnavgs = OperatorBase('avgs', [1, 2], fp(ext(ty_clamp(auto_extension, -1))), cname = 'avgs', sqlname = 'AVGS', call = windowed_fn_behavor)
+fnvars = OperatorBase('vars', [1, 2], fp(ext(ty_clamp(auto_extension, -1))), cname = 'vars', sqlname = 'VARS', call = windowed_fn_behavor)
+fnstds = OperatorBase('stddevs', [1, 2], fp(ext(ty_clamp(auto_extension, -1))), cname = 'stddevs', sqlname = 'STDDEVS', call = windowed_fn_behavor)
 fncnt = OperatorBase('count', 1, int_return, cname = 'count', sqlname = 'COUNT', call = count_behavior)
 fnpack = OperatorBase('pack', -1, pack_return, cname = 'pack', sqlname = 'PACK', call = pack_behavior)
 # special
@@ -361,7 +365,8 @@ builtin_cstdlib = _op_make_dict(fnsqrt, fnlog, fnsin, fncos, fntan, fnpow)
 builtin_func = _op_make_dict(fnmax, fnmin, fnsum, fnavg, fnmaxs, 
                              fnmins, fndeltas, fnratios, fnlast,
                              fnfirst, fnsums, fnavgs, fncnt, 
-                             fnpack, fntrunc, fnprev, fnnext)
+                             fnpack, fntrunc, fnprev, fnnext, 
+                             fnvar, fnvars, fnstd, fnstds)
 user_module_func = {}
 builtin_operators : Dict[str, OperatorBase] = {**builtin_binary_arith, **builtin_binary_logical, 
     **builtin_unary_arith, **builtin_unary_logical, **builtin_unary_special, **builtin_func, **builtin_cstdlib, 
diff --git a/prompt.py b/prompt.py
index cc6cb15..f257b49 100644
--- a/prompt.py
+++ b/prompt.py
@@ -160,9 +160,11 @@ class QueryStats:
 class Config:
     __all_attrs__ = ['running', 'new_query', 'server_mode', 
                      'backend_type', 'has_dll', 
-                     'postproc_time', 'sql_time', 
-                     'n_buffers'
+                     'n_buffers',
                      ]
+    __i64_attrs__ = [
+                     'monetdb_time', 'postproc_time'
+                    ]
     __init_attributes__ = False
     
     @staticmethod
@@ -171,26 +173,42 @@ class Config:
             from functools import partial
             for _i, attr in enumerate(Config.__all_attrs__):
                 if not hasattr(Config, attr):
-                    setattr(Config, attr, property(partial(Config.getter, i = _i), partial(Config.setter, i = _i)))
+                    setattr(Config, attr, property(
+                        partial(Config.getter, i = _i), partial(Config.setter, i = _i)
+                    ))
+            for _i, attr in enumerate(Config.__i64_attrs__):
+                if not hasattr(Config, attr):
+                    setattr(Config, attr, property(
+                        partial(Config.i64_getter, i = _i), partial(Config.i64_setter, i = _i)
+                    ))
             Config.__init_attributes__ = True
             
     def __init__(self, mode, nq = 0, n_bufs = 0, bf_szs = []) -> None:
         Config.__init_self__()
-        self.int_size = 4
         self.n_attrib = len(Config.__all_attrs__)
-        self.buf = bytearray((self.n_attrib + n_bufs) * self.int_size)
-        self.np_buf = np.ndarray(shape=(self.n_attrib), buffer=self.buf, dtype=np.int32)
+        self.buf = bytearray((self.n_attrib + n_bufs) * 4 +
+                              len(self.__i64_attrs__) * 8
+                             )
+        self.np_buf = np.ndarray(shape = (self.n_attrib), buffer = self.buf, dtype = np.int32)
+        self.np_i64buf = np.ndarray(shape = len(self.__i64_attrs__), buffer = self.buf, 
+                                    dtype = np.int64, offset = 4 * len(self.__all_attrs__))
         self.new_query = nq
         self.server_mode = mode.value 
         self.running = 1
         self.backend_type = Backend_Type.BACKEND_AQuery.value
         self.has_dll = 0
         self.n_buffers = n_bufs
+        self.monetdb_time = 0
+        self.postproc_time = 0
         
     def getter (self, *, i):
         return self.np_buf[i]
     def setter(self, v, *, i):
         self.np_buf[i] = v
+    def i64_getter (self, *, i):
+        return self.np_i64buf[i]
+    def i64_setter(self, v, *, i):
+        self.np_i64buf[i] = v
 
     def set_bufszs(self, buf_szs):
         for i in range(min(len(buf_szs), self.n_buffers)):
@@ -209,6 +227,8 @@ class PromptState():
     test_parser = True
     server_mode: RunType = RunType.Threaded
     server_bin = 'server.bin' if server_mode == RunType.IPC else 'server.so'
+    wait_engine = lambda: None
+    wake_engine = lambda: None
     set_ready = lambda: None
     get_ready = lambda: None
     server_status = lambda: False
@@ -299,12 +319,14 @@ def init_threaded(state : PromptState):
     if aquery_config.run_backend:    
         server_so = ctypes.CDLL('./'+state.server_bin)
         state.send = server_so['receive_args']
+        state.wait_engine = server_so['wait_engine']
+        state.wake_engine = server_so['wake_engine']
         aquery_config.have_hge = server_so['have_hge']()
         if aquery_config.have_hge != 0:
             from engine.types import get_int128_support
             get_int128_support()
         state.th = threading.Thread(target=server_so['main'], args=(-1, ctypes.POINTER(ctypes.c_char_p)(state.cfg.c)), daemon=True)
-        state.th.start()
+        state.th.start() 
 
 def init_prompt() -> PromptState:
     aquery_config.init_config()
@@ -337,6 +359,8 @@ def init_prompt() -> PromptState:
         rm = lambda: None
         def __set_ready():
             state.cfg.new_query = 1
+            state.wake_engine()
+            
         state.set_ready = __set_ready
         state.get_ready = lambda: aquery_config.run_backend and state.cfg.new_query
         if aquery_config.run_backend:
@@ -380,9 +404,16 @@ def prompt(running = lambda:True, next = lambda:input('> '), state = None):
     while running():
         try:
             if state.server_status():
-                state.init()
+                state.init(state)
+            # *** busy waiting ***
+            # while state.get_ready():
+            #     time.sleep(.00001)
             while state.get_ready():
-                time.sleep(.00001)
+                state.wait_engine()
+                if state.need_print:
+                    print(f'MonetDB Time: {state.cfg.monetdb_time/10**9}, '
+                          f'PostProc Time: {state.cfg.postproc_time/10**9}')
+                    state.cfg.monetdb_time = state.cfg.postproc_time = 0
             state.currstats.print(state.stats, need_print=state.need_print)
             try:
                 og_q : str = next()
diff --git a/reconstruct/ast.py b/reconstruct/ast.py
index 66342df..c95223d 100644
--- a/reconstruct/ast.py
+++ b/reconstruct/ast.py
@@ -54,19 +54,28 @@ class ast_node:
             self.context.sql_end()
         
 from reconstruct.expr import expr, fastscan
-
-
+class SubqType(Enum):
+    WITH = auto()
+    FROM = auto()
+    PROJECTION = auto()
+    FILTER = auto()
+    GROUPBY = auto()
+    ORDERBY = auto()
+    NONE = auto()
 class projection(ast_node):
     name = 'projection'
     first_order = 'select'
-    
+
+        
     def __init__(self, 
                  parent : Optional["ast_node"],
                  node, 
                  context : Optional[Context] = None,
-                 force_use_spgb : bool = False
+                 force_use_spgb : bool = False,
+                 subq_type: SubqType = SubqType.NONE
                 ):
         self.force_use_spgb = force_use_spgb
+        self.subq_type = subq_type
         super().__init__(parent, node, context)
         
     def init(self, _):
@@ -83,9 +92,21 @@ class projection(ast_node):
             p = node['select_distinct']
             self.distinct = True
         if 'with' in node:
-            self.with_clause = projection(self, node['value'])
+            with_table = node['with']['name']
+            with_table_name = tuple(with_table.keys())[0]
+            with_table_cols = tuple(with_table.values())[0]
+            self.with_clause = projection(self, node['with']['value'], subq_type=SubqType.WITH)
+            self.with_clause.out_table.add_alias(with_table_name)
+            for new_name, col in zip(with_table_cols, self.with_clause.out_table.columns):
+                col.rename(new_name)
+            self.with_clause.out_table.contextname_cpp 
+            # in monetdb, in cxt 
         else:
             self.with_clause = None
+        
+        self.limit = None
+        if 'limit' in node:
+            self.limit = node['limit']
             
         self.projections = p if type(p) is list else [p]
         if self.parent is None:
@@ -115,8 +136,9 @@ class projection(ast_node):
         if type(self.datasource) is join:
             self.datasource.process_join_conditions()
         
+        self.context.special_gb = self.force_use_spgb
         if 'groupby' in node: # if groupby clause contains special stuff
-            self.context.special_gb = groupby.check_special(self, node['groupby'])
+            self.context.special_gb |= groupby.check_special(self, node['groupby'])
 
     def consume(self, node):
         # deal with projections
@@ -230,7 +252,7 @@ class projection(ast_node):
             self.group_node = groupby(self, node['groupby'])
             if self.group_node.terminate:
                 self.context.abandon_query()
-                projection(self.parent, node, self.context, True)
+                projection(self.parent, node, self.context, True, subq_type=self.subq_type)
                 return
             if self.group_node.use_sp_gb:
                 self.has_postproc = True
@@ -370,8 +392,12 @@ class projection(ast_node):
                     # for funcs evaluate f_i(x, ...)
                     self.context.emitc(f'{self.out_table.contextname_cpp}->get_col<{key}>().initfrom({val[1]}, "{cols[i].name}");')
         # print out col_is
-        if 'into' not in node:
-            self.context.emitc(f'print(*{self.out_table.contextname_cpp});')
+        
+        if 'into' not in node and self.subq_type == SubqType.NONE:
+            if self.limit is None:
+                self.context.emitc(f'print(*{self.out_table.contextname_cpp});')
+            else:
+                self.context.emitc(f'{self.out_table.contextname_cpp}->printall(" ","\\n", nullptr, nullptr, {self.limit});')
         
         if self.outfile:
             self.outfile.finalize()
@@ -627,7 +653,7 @@ class groupby(ast_node):
         self.gb_cols = set()
         # dedicated_glist -> cols populated for special group by
         self.dedicated_glist : List[Tuple[expr, Set[ColRef]]] = []
-        self.use_sp_gb = False
+        self.use_sp_gb = self.parent.force_use_spgb
         for g in node:
             self.datasource.rec = set()
             g_expr = expr(self, g['value'])
@@ -654,12 +680,13 @@ class groupby(ast_node):
             if (projs[2].is_compound and 
                 not ((projs[2].is_ColExpr and projs[2].raw_col in self.gb_cols) or
                 projs[2].sql in self.gb_cols)
-                ):
-                if self.parent.force_use_spgb:
+                ) and (not self.parent.force_use_spgb):
                     self.use_sp_gb = True
-                else:    
-                    self.terminate = True
-                    return
+                    break
+                
+        if self.use_sp_gb and not self.parent.force_use_spgb:
+            self.terminate = True
+            return
         if not self.use_sp_gb:
             self.dedicated_gb = None
             self.add(', '.join(o_list))
@@ -1144,7 +1171,7 @@ class load(ast_node):
             self.context.emitc(f'{c.cxt_name}.emplace_back({col_tmp_names[i]});')
             
         self.context.emitc('}')
-        self.context.emitc(f'print(*{self.out_table});')
+        # self.context.emitc(f'print(*{self.out_table});')
         self.context.emitc(f'{self.out_table}->monetdb_append_table(cxt->alt_server, "{table.table_name}");')
         
         self.context.postproc_end(self.postproc_fname)
diff --git a/reconstruct/expr.py b/reconstruct/expr.py
index bfd552c..e22a4ed 100644
--- a/reconstruct/expr.py
+++ b/reconstruct/expr.py
@@ -168,7 +168,7 @@ class expr(ast_node):
                             
                         special_func = [*self.context.udf_map.keys(), *self.context.module_map.keys(), 
                                         "maxs", "mins", "avgs", "sums", "deltas", "last", "first", 
-                                        "ratios", "pack", "truncate"]
+                                        "stddevs", "vars", "ratios", "pack", "truncate"]
                         
                         if (
                                 self.context.special_gb 
diff --git a/reconstruct/storage.py b/reconstruct/storage.py
index 47eab9a..98ad799 100644
--- a/reconstruct/storage.py
+++ b/reconstruct/storage.py
@@ -45,6 +45,14 @@ class ColRef:
             alias = table_name
         return f'{alias}.{self.get_name()}'
     
+    def rename(self, name):
+        self.alias.discard(self.name)
+        self.table.columns_byname.pop(self.name, None)
+        self.name = name
+        self.table.columns_byname[name] = self
+        
+        return self
+    
     def __getitem__(self, key):
         if type(key) is str:
             return getattr(self, key)
@@ -97,6 +105,17 @@ class TableInfo:
             return
         self.cxt.tables_byname[alias] = self
         self.alias.add(alias)
+    
+    def rename(self, name):
+        if name in self.cxt.tables_byname.keys():
+            print(f"Error: table name {name} already exists")
+            return
+        
+        self.cxt.tables_byname.pop(self.table_name, None)
+        self.alias.discard(self.table_name)
+        self.table_name = name
+        self.cxt.tables_byname[name] = self
+        self.alias.add(name)
         
     def parse_col_names(self, colExpr) -> ColRef:
         parsedColExpr = colExpr.split('.')
diff --git a/server/aggregations.h b/server/aggregations.h
index 5338e23..cb4bcbe 100644
--- a/server/aggregations.h
+++ b/server/aggregations.h
@@ -202,6 +202,102 @@ decayed_t<VT, types::GetFPType<types::GetLongType<T>>> avgw(uint32_t w, const VT
 	return ret;
 }
 
+template<class T, template<typename ...> class VT, bool sd = false>
+decayed_t<VT, types::GetFPType<types::GetLongType<T>>> varw(uint32_t w, const VT<T>& arr) {
+	using FPType = types::GetFPType<types::GetLongType<T>>;
+	const uint32_t& len = arr.size;
+	decayed_t<VT, FPType> ret(len);
+	uint32_t i = 0;
+	types::GetLongType<T> s{};
+	w = w > len ? len : w;
+	FPType EnX {},  MnX{};
+	if (len) {
+		s = arr[0];
+		MnX = 0;
+		EnX = arr[0];
+		ret[i++] = 0;
+	}
+	for (; i < len; ++i){
+		s += arr[i];
+		FPType _EnX = s / (FPType)(i + 1);
+		MnX += (arr[i] - EnX) * (arr[i] - _EnX);
+		EnX = _EnX;
+		ret[i] = MnX / (FPType)(i + 1);
+		if constexpr(sd) ret[i-1] = sqrt(ret[i-1]);
+	}
+	const float rw = 1.f / (float)w;
+	s *= rw;	
+	for (; i < len; ++i){
+		const auto dw = arr[i] - arr[i - w - 1];
+		const auto sw = arr[i] + arr[i - w - 1];
+		const auto dex = dw * rw;
+		ret[i] = ret[i-1] - dex*(s + s + dex - sw);
+		if constexpr(sd) ret[i-1] = sqrt(ret[i-1]);
+		s += dex;
+	}
+	if constexpr(sd) 
+		if(i)
+			ret[i-1] = sqrt(ret[i-1]);
+	
+	return ret;
+}
+
+template<class T, template<typename ...> class VT>
+types::GetFPType<types::GetLongType<decays<T>>> var(const VT<T>& arr) {
+	typedef types::GetFPType<types::GetLongType<decays<T>>> FPType;
+	const uint32_t& len = arr.size;
+	uint32_t i = 0;
+	types::GetLongType<T> s{0};
+	types::GetLongType<T> ssq{0};
+	if (len) {
+		s = arr[0];
+		ssq = arr[0] * arr[0];
+	}
+	for (; i < len; ++i){
+		s += arr[i];
+		ssq += arr[i] * arr[i];
+	}
+	return (ssq - s * s / (FPType)(len + 1)) / (FPType)(len + 1);
+}
+
+template<class T, template<typename ...> class VT, bool sd = false>
+decayed_t<VT, types::GetFPType<types::GetLongType<T>>> vars(const VT<T>& arr) {
+	typedef types::GetFPType<types::GetLongType<T>> FPType;
+	const uint32_t& len = arr.size;
+	decayed_t<VT, FPType> ret(len);
+	uint32_t i = 0;
+	types::GetLongType<T> s{};
+	FPType MnX{};
+	FPType EnX {};
+	if (len) {
+		s = arr[0];
+		MnX = 0;
+		EnX = arr[0];
+		ret[i++] = 0;
+	}
+	for (; i < len; ++i){
+		s += arr[i];
+		FPType _EnX = s / (FPType)(i + 1);
+		MnX += (arr[i] - EnX) * (arr[i] - _EnX);
+		printf("%d %ld ", arr[i], MnX);
+		EnX = _EnX;
+		ret[i] = MnX / (FPType)(i + 1);
+		if constexpr(sd) ret[i] = sqrt(ret[i]);
+	}
+	return ret;
+}
+template<class T, template<typename ...> class VT>
+types::GetFPType<types::GetLongType<decays<T>>> stddev(const VT<T>& arr) {
+	return sqrt(var(arr));
+}
+template<class T, template<typename ...> class VT>
+decayed_t<VT, types::GetFPType<types::GetLongType<T>>> stddevs(const VT<T>& arr) {
+	return vars<T, VT, true>(arr);
+}
+template<class T, template<typename ...> class VT>
+decayed_t<VT, types::GetFPType<types::GetLongType<T>>> stddevw(uint32_t w, const VT<T>& arr) {
+	return varw<T, VT, true>(w, arr);
+}
 // use getSignedType
 template<class T, template<typename ...> class VT>
 decayed_t<VT, T> deltas(const VT<T>& arr) {
@@ -251,26 +347,33 @@ T first(const VT<T>& arr) {
 }
 
 
+
 #define __DEFAULT_AGGREGATE_FUNCTION__(NAME, RET) \
-template <class T> constexpr inline T NAME(const T& v) { return RET; }
+template <class T> constexpr T NAME(const T& v) { return RET; }
 
 // non-aggreation count. E.g. SELECT COUNT(col) from table; 
-template <class T> constexpr inline T count(const T& v) { return 1; }
-template <class T> constexpr inline T max(const T& v) { return v; }
-template <class T> constexpr inline T min(const T& v) { return v; }
-template <class T> constexpr inline T avg(const T& v) { return v; }
-template <class T> constexpr inline T sum(const T& v) { return v; }
-template <class T> constexpr inline T maxw(uint32_t, const T& v) { return v; }
-template <class T> constexpr inline T minw(uint32_t, const T& v) { return v; }
-template <class T> constexpr inline T avgw(uint32_t, const T& v) { return v; }
-template <class T> constexpr inline T sumw(uint32_t, const T& v) { return v; }
-template <class T> constexpr inline T ratiow(uint32_t, const T& v) { return 1; }
-template <class T> constexpr inline T maxs(const T& v) { return v; }
-template <class T> constexpr inline T mins(const T& v) { return v; }
-template <class T> constexpr inline T avgs(const T& v) { return v; }
-template <class T> constexpr inline T sums(const T& v) { return v; }
-template <class T> constexpr inline T last(const T& v) { return v; }
-template <class T> constexpr inline T prev(const T& v) { return v; }
-template <class T> constexpr inline T aggnext(const T& v) { return v; }
-template <class T> constexpr inline T daltas(const T& v) { return 0; }
-template <class T> constexpr inline T ratios(const T& v) { return 1; }
+template <class T> constexpr T count(const T&) { return 1; }
+template <class T> constexpr T var(const T&) { return 0; }
+template <class T> constexpr T vars(const T&) { return 0; }
+template <class T> constexpr T varw(uint32_t, const T&) { return 0; }
+template <class T> constexpr T stddev(const T&) { return 0; }
+template <class T> constexpr T stddevs(const T&) { return 0; }
+template <class T> constexpr T stddevw(uint32_t, const T&) { return 0; }
+template <class T> constexpr T max(const T& v) { return v; }
+template <class T> constexpr T min(const T& v) { return v; }
+template <class T> constexpr T avg(const T& v) { return v; }
+template <class T> constexpr T sum(const T& v) { return v; }
+template <class T> constexpr T maxw(uint32_t, const T& v) { return v; }
+template <class T> constexpr T minw(uint32_t, const T& v) { return v; }
+template <class T> constexpr T avgw(uint32_t, const T& v) { return v; }
+template <class T> constexpr T sumw(uint32_t, const T& v) { return v; }
+template <class T> constexpr T ratiow(uint32_t, const T&) { return 1; }
+template <class T> constexpr T maxs(const T& v) { return v; }
+template <class T> constexpr T mins(const T& v) { return v; }
+template <class T> constexpr T avgs(const T& v) { return v; }
+template <class T> constexpr T sums(const T& v) { return v; }
+template <class T> constexpr T last(const T& v) { return v; }
+template <class T> constexpr T prev(const T& v) { return v; }
+template <class T> constexpr T aggnext(const T& v) { return v; }
+template <class T> constexpr T daltas(const T&) { return 0; }
+template <class T> constexpr T ratios(const T&) { return 1; }
diff --git a/server/libaquery.h b/server/libaquery.h
index 551d205..6227af9 100644
--- a/server/libaquery.h
+++ b/server/libaquery.h
@@ -3,6 +3,7 @@
 
 #include "table.h"
 #include <unordered_map>
+#include <chrono>
 
 enum Log_level {
 	LOG_INFO,
@@ -15,9 +16,16 @@ enum Backend_Type {
 	BACKEND_MonetDB,
 	BACKEND_MariaDB
 };
+
+struct QueryStats{
+	long long monet_time;
+	long long postproc_time;
+};
 struct Config{
-    int running, new_query, server_mode,
-	 	backend_type, has_dll, exec_time, n_buffers;
+    int running, new_query, server_mode, 
+	 	backend_type, has_dll, 
+		n_buffers;
+	QueryStats stats;
     int buffer_sizes[];
 };
 
@@ -67,6 +75,27 @@ struct Context{
     std::unordered_map<const char*, uColRef *> cols;
 };
 
+class aq_timer {
+private:
+	std::chrono::high_resolution_clock::time_point now;
+public:
+	aq_timer(){
+		now = std::chrono::high_resolution_clock::now();
+	}
+	void reset(){
+		now = std::chrono::high_resolution_clock::now();
+	}
+	long long elapsed(){
+		long long ret = (std::chrono::high_resolution_clock::now() - now).count();
+		reset();
+		return ret;
+	}
+	long long lap() const{
+		long long ret = (std::chrono::high_resolution_clock::now() - now).count();
+		return ret;
+	}
+};
+
 #ifdef _WIN32
 #define __DLLEXPORT__  __declspec(dllexport) __stdcall 
 #else 
diff --git a/server/server.cpp b/server/server.cpp
index 2105545..6a9bc43 100644
--- a/server/server.cpp
+++ b/server/server.cpp
@@ -18,6 +18,7 @@
 #include <sys/mman.h>
 struct SharedMemory
 {
+    std::atomic<bool> a;
     int hFileMap;
     void* pData;
     SharedMemory(const char* fname) {
@@ -31,6 +32,79 @@ struct SharedMemory
 
     }
 };
+#ifndef __USE_STD_SEMAPHORE__
+#ifdef __APPLE__
+#include <dispatch/dispatch.h>
+class A_Semaphore {
+private:
+	dispatch_semaphore_t native_handle;
+public:
+	A_Semaphore(bool v = false) {
+		native_handle = dispatch_semaphore_create(v);
+	}
+	void acquire() {
+        puts("acquire");
+		dispatch_semaphore_wait(native_handle, DISPATCH_TIME_FOREVER);
+	}
+	void release() {
+        puts("release");
+		dispatch_semaphore_signal(native_handle);
+	}
+	~A_Semaphore() {
+	}
+};
+#else
+#include <semaphore.h>
+class A_Semaphore {
+private:
+	sem_t native_handle;
+public:
+	A_Semaphore(bool v = false) {
+		sem_init(&native_handle, v, 1);
+	}
+	void acquire() {
+		sem_wait(&native_handle);
+	}
+	void release() {
+		sem_post(&native_handle);
+	}
+	~A_Semaphore() {
+		sem_destroy(&native_handle);
+	}
+};
+#endif
+#endif
+
+#endif
+#ifdef __USE_STD_SEMAPHORE__
+#include <semaphore>
+class A_Semaphore {
+private:
+    std::binary_semaphore native_handle;
+public:
+    A_Semaphore(bool v = false) {
+        native_handle = std::binary_semaphore(v);
+    }
+    void acquire() {
+        native_handle.acquire();
+    }
+    void release() {
+        native_handle.release();
+    }
+    ~A_Semaphore() { }
+};
+#endif
+#ifdef __AQUERY_ITC_USE_SHMEM__
+A_Semaphore prompt{ true }, engine{ false };
+#define PROMPT_ACQUIRE() prompt.acquire()
+#define PROMPT_RELEASE() prompt.release()
+#define ENGINE_ACQUIRE() engine.acquire()
+#define ENGINE_RELEASE() engine.release()
+#else
+#define PROMPT_ACQUIRE() 
+#define PROMPT_RELEASE() std::this_thread::sleep_for(std::chrono::nanoseconds(0))
+#define ENGINE_ACQUIRE() 
+#define ENGINE_RELEASE() 
 #endif
 
 #include "aggregations.h"
@@ -42,6 +116,13 @@ int test_main();
 int n_recv = 0;
 char** n_recvd = nullptr;
 
+__AQEXPORT__(void) wait_engine(){
+    PROMPT_ACQUIRE();
+}
+__AQEXPORT__(void) wake_engine(){
+    ENGINE_RELEASE();
+}
+
 extern "C" void __DLLEXPORT__ receive_args(int argc, char**argv){
     n_recv = argc;
     n_recvd = argv;
@@ -119,15 +200,16 @@ void initialize_module(const char* module_name, void* module_handle, Context* cx
 }
 
 int dll_main(int argc, char** argv, Context* cxt){
+    aq_timer timer;
     Config *cfg = reinterpret_cast<Config *>(argv[0]);
     std::unordered_map<std::string, void*> user_module_map;
-    if (cxt->module_function_maps == 0)
+    if (cxt->module_function_maps == nullptr)
         cxt->module_function_maps = new std::unordered_map<std::string, void*>();
     auto module_fn_map = 
         static_cast<std::unordered_map<std::string, void*>*>(cxt->module_function_maps);
     
     auto buf_szs = cfg->buffer_sizes;
-    void** buffers = (void**)malloc(sizeof(void*) * cfg->n_buffers);
+    void** buffers = (void**) malloc (sizeof(void*) * cfg->n_buffers);
     for (int i = 0; i < cfg->n_buffers; i++) 
         buffers[i] = static_cast<void *>(argv[i + 1]);
 
@@ -136,18 +218,22 @@ int dll_main(int argc, char** argv, Context* cxt){
     cxt->n_buffers = cfg->n_buffers;
     cxt->sz_bufs = buf_szs;
     cxt->alt_server = NULL;
-
+    
     while(cfg->running){
+        ENGINE_ACQUIRE();
         if (cfg->new_query) {
-            void *handle = 0;
-            void *user_module_handle = 0;
+            cfg->stats.postproc_time = 0;
+            cfg->stats.monet_time = 0;
+
+            void *handle = nullptr;
+            void *user_module_handle = nullptr;
             if (cfg->backend_type == BACKEND_MonetDB){
-                if (cxt->alt_server == 0)
+                if (cxt->alt_server == nullptr)
                     cxt->alt_server = new Server(cxt);
                 Server* server = reinterpret_cast<Server*>(cxt->alt_server);
                 if(n_recv > 0){
                     if (cfg->backend_type == BACKEND_AQuery || cfg->has_dll) {
-                        handle = dlopen("./dll.so", RTLD_LAZY);
+                        handle = dlopen("./dll.so", RTLD_NOW);
                     }
                     for (const auto& module : user_module_map){
                         initialize_module(module.first.c_str(), module.second, cxt);
@@ -159,14 +245,18 @@ int dll_main(int argc, char** argv, Context* cxt){
                         switch(n_recvd[i][0]){
                         case 'Q': // SQL query for monetdbe
                             {
+                                timer.reset();
                                 server->exec(n_recvd[i] + 1);
+                                cfg->stats.monet_time += timer.elapsed();
                                 printf("Exec Q%d: %s", i, n_recvd[i]);
                             }
                             break;
                         case 'P': // Postprocessing procedure 
                             if(handle && !server->haserror()) {
                                 code_snippet c = reinterpret_cast<code_snippet>(dlsym(handle, n_recvd[i]+1));
+                                timer.reset();
                                 c(cxt);
+                                cfg->stats.postproc_time += timer.elapsed();
                             }
                             break;
                         case 'M': // Load Module
@@ -198,7 +288,7 @@ int dll_main(int argc, char** argv, Context* cxt){
                                 auto mname = n_recvd[i] + 1;
                                 auto it = user_module_map.find(mname);
                                 if (user_module_handle == it->second)
-                                    user_module_handle = 0;
+                                    user_module_handle = nullptr;
                                 dlclose(it->second);
                                 user_module_map.erase(it);
                             }
@@ -207,8 +297,9 @@ int dll_main(int argc, char** argv, Context* cxt){
                     }
                     if(handle) {
                         dlclose(handle);
-                        handle = 0;
+                        handle = nullptr;
                     }
+                    printf("%ld, %ld", cfg->stats.monet_time, cfg->stats.postproc_time);
                     cxt->end_session();
                     n_recv = 0;
                 }
@@ -230,9 +321,11 @@ int dll_main(int argc, char** argv, Context* cxt){
             if (handle) dlclose(handle);
             cfg->new_query = 0;
         }
-        std::this_thread::sleep_for(std::chrono::milliseconds(100));
+        //puts(cfg->running? "true": "false");
+        asm("");
+        PROMPT_RELEASE();
     }
-
+    
     return 0;
 }
 
diff --git a/server/table.h b/server/table.h
index da75cc1..20e2449 100644
--- a/server/table.h
+++ b/server/table.h
@@ -9,6 +9,7 @@
 #include <string>
 #include <algorithm>
 #include <cstdarg>
+#include <vector>
 #include "io.h"
 #include "hasher.h"
 
@@ -139,8 +140,16 @@ public:
 	ColView<_Ty> operator [](const vector_type<uint32_t>& idxs) const {
 		return ColView<_Ty>(*this, idxs);
 	}
-
-	void out(uint32_t n = 4, const char* sep = " ") const {
+	vector_type<_Ty> operator [](const std::vector<bool>& idxs) const {
+		vector_type<_Ty> ret (this->size);
+		uint32_t i = 0;
+		for(const auto& f : idxs){
+			if(f) ret.emplace_back(this->operator[](i));
+			++i;
+		}
+		return ret;
+	}
+	void out(uint32_t n = 1000, const char* sep = " ") const {
 		const char* more = "";
 		if (n < this->size)
 			more = " ... ";
@@ -243,7 +252,7 @@ public:
 	Iterator_t end() const {
 		return Iterator_t(idxs.end(), orig);
 	}
-	void out(uint32_t n = 4, const char* sep = " ") const {
+	void out(uint32_t n = 1000, const char* sep = " ") const {
 		n = n > size ? size : n;
 		std::cout << '(';
 		for (uint32_t i = 0; i < n; ++i)
@@ -438,19 +447,27 @@ struct TableInfo {
 	}
 	template <int ...cols>
 	void print2(const char* __restrict sep = ",", const char* __restrict end = "\n",
-		const vector_type<uint32_t>* __restrict view = nullptr, FILE* __restrict fp = nullptr) const {
+		const vector_type<uint32_t>* __restrict view = nullptr, 
+		FILE* __restrict fp = nullptr, uint32_t limit = std::numeric_limits<uint32_t>::max()
+		) const {
 
 		std::string printf_string =
 			generate_printf_string<typename std::tuple_element<cols, tuple_type>::type ...>(sep, end);
+		// puts(printf_string.c_str());
 		std::string header_string = std::string();
 		constexpr static int a_cols[] = { cols... };
-		for (int i = 0; i < sizeof...(cols); ++i)
-			header_string += std::string(this->colrefs[a_cols[i]].name) + sep;
-		const size_t l_sep = strlen(sep);
-		if (header_string.size() - l_sep >= 0)
-			header_string.resize(header_string.size() - l_sep);
-
-		const auto& prt_loop = [&fp, &view, &printf_string, *this](const auto& f) {
+		if (fp == nullptr){
+			header_string = get_header_string(sep, end);
+			header_string.resize(header_string.size() - strlen(end));
+		}
+		else {
+			for (int i = 0; i < sizeof...(cols); ++i)
+				header_string += std::string(this->colrefs[a_cols[i]].name) + sep;
+			const size_t l_sep = strlen(sep);
+			if (header_string.size() - l_sep >= 0)
+				header_string.resize(header_string.size() - l_sep);
+		}
+		const auto& prt_loop = [&fp, &view, &printf_string, *this, &limit](const auto& f) {
 #ifdef __AQ__HAS__INT128__			
 			constexpr auto num_hge = count_type<__int128_t, __uint128_t>((tuple_type*)(0));
 #else
@@ -466,16 +483,21 @@ struct TableInfo {
 				+ 1 // padding for msvc not allowing empty arrays
 			];
 			setgbuf(cbuf);
-			if (view)
-				for (uint32_t i = 0; i < view->size; ++i) {
+			
+			if (view){
+				uint32_t outsz = limit > view->size ? view->size : limit;
+				for (uint32_t i = 0; i < outsz; ++i) {
 					print2_impl<cols...>(f, (*view)[i], printf_string.c_str());
 					setgbuf();
 				}
-			else
-				for (uint32_t i = 0; i < colrefs[0].size; ++i) {
+			}
+			else{
+				uint32_t outsz = limit > colrefs[0].size ? colrefs[0].size : limit;
+				for (uint32_t i = 0; i < outsz; ++i) {
 					print2_impl<cols...>(f, i, printf_string.c_str());
 					setgbuf();
 				}
+			}
 		};
 
 		if (fp)
@@ -490,15 +512,17 @@ struct TableInfo {
 	}
 	template <int ...vals> struct applier {
 		inline constexpr static void apply(const TableInfo<Types...>& t, const char* __restrict sep = ",", const char* __restrict end = "\n",
-			const vector_type<uint32_t>* __restrict view = nullptr, FILE* __restrict fp = nullptr)
+			const vector_type<uint32_t>* __restrict view = nullptr, FILE* __restrict fp = nullptr, uint32_t limit = std::numeric_limits<uint32_t>::max()
+			) 
 		{
-			t.template print2<vals ...>(sep, end, view, fp);
+			t.template print2<vals ...>(sep, end, view, fp, limit);
 		}
 	};
 
 	inline void printall(const char* __restrict sep = ",", const char* __restrict end = "\n",
-		const vector_type<uint32_t>* __restrict view = nullptr, FILE* __restrict fp = nullptr) {
-		applyIntegerSequence<sizeof...(Types), applier>::apply(*this, sep, end, view, fp);
+		const vector_type<uint32_t>* __restrict view = nullptr, FILE* __restrict fp = nullptr, 
+		uint32_t limit = std::numeric_limits<uint32_t>::max() ) const {
+		applyIntegerSequence<sizeof...(Types), applier>::apply(*this, sep, end, view, fp, limit);
 	}
 
 	TableInfo<Types...>* rename(const char* name) {
@@ -667,7 +691,9 @@ template <class ...Types>
 template <size_t j>
 inline typename std::enable_if<j == sizeof...(Types) - 1, void>::type
 TableInfo<Types ...>::print_impl(const uint32_t& i, const char* __restrict sep) const {
-	std::cout << (get<j>(*this))[i];
+	decltype(auto) t = (get<j>(*this))[i];
+//	print(t);
+	std::cout << t;
 }
 
 template<class ...Types>
@@ -682,6 +708,7 @@ inline typename std::enable_if < j < sizeof...(Types) - 1, void>::type
 template<class ...Types>
 inline void TableInfo<Types...>::print(const char* __restrict sep, const char* __restrict end) const {
 
+	//printall(sep, end);
 	std::string header_string = get_header_string(sep, end);
 	std::cout << header_string.c_str();
 
diff --git a/server/types.h b/server/types.h
index 3ae14b6..20cb0fc 100644
--- a/server/types.h
+++ b/server/types.h
@@ -29,27 +29,37 @@ inline constexpr size_t aq_szof<void> = 0;
 template <class T1, class T2>
 struct aqis_same_impl {
 	constexpr static bool value = 
+		
 		std::conditional_t<
-			std::is_signed_v<T1> == std::is_signed_v<T2>,
+			std::is_same_v<T1, bool> || std::is_same_v<T2, bool>, 
+			Cond(
+				(std::is_same_v<T1, bool> && std::is_same_v<T2, bool>), 
+				std::true_type, 
+				std::false_type
+			),
 			Cond(
-				std::is_floating_point_v<T1> == std::is_floating_point_v<T2>,
+				std::is_signed_v<T1> == std::is_signed_v<T2>,
 				Cond(
-					aq_szof<T1> == aq_szof<T2>, // deal with sizeof(void)
-					std::true_type,
+					std::is_floating_point_v<T1> == std::is_floating_point_v<T2>,
+					Cond(
+						aq_szof<T1> == aq_szof<T2>, // deal with sizeof(void)
+						std::true_type,
+						std::false_type
+					),
 					std::false_type
 				),
 				std::false_type
-			),
-			std::false_type
+			)
 		>::value;
 };
-
+// make sure size_t/ptr_t and the corresponding integer types are the same
 template <class T1, class T2, class ...Ts>
 constexpr bool aqis_same = aqis_same_impl<T1, T2>::value &&
 aqis_same<T2, Ts...>;
 
 template <class T1, class T2>
 constexpr bool aqis_same<T1, T2> = aqis_same_impl<T1, T2>::value;
+
 namespace types {
 	enum Type_t {
 		AINT32, AFLOAT, ASTR, ADOUBLE, ALDOUBLE, AINT64, AINT128, AINT16, ADATE, ATIME, AINT8,
diff --git a/server/vector_type.hpp b/server/vector_type.hpp
index 98d79f5..3ad5fcc 100644
--- a/server/vector_type.hpp
+++ b/server/vector_type.hpp
@@ -265,7 +265,7 @@ public:
 		}
 		size = this->size + dist;
 	}
-	inline void out(uint32_t n = 4, const char* sep = " ") const
+	inline void out(uint32_t n = 4000, const char* sep = " ") const
 	{
 		const char* more = "";
 		if (n < this->size)
diff --git a/server/winhelper.cpp b/server/winhelper.cpp
index 48bfa86..d59f58b 100644
--- a/server/winhelper.cpp
+++ b/server/winhelper.cpp
@@ -41,4 +41,20 @@ void SharedMemory::FreeMemoryMap()
         if (this->hFileMap)
             CloseHandle(this->hFileMap);
 }
+
+#ifndef __USE_STD_SEMAPHORE__
+A_Semaphore::A_Semaphore(bool v = false) {
+    native_handle = CreateSemaphore(NULL, v, 1, NULL);
+}
+void A_Semaphore::acquire() {
+    WaitForSingleObject(native_handle, INFINITE);
+}
+void A_Semaphore::release() {
+    ReleaseSemaphore(native_handle, 1, NULL);
+}
+A_Semaphore::~A_Semaphore() {
+    CloseHandle(native_handle);
+}
+#endif
+
 #endif
diff --git a/server/winhelper.h b/server/winhelper.h
index df9231e..f39c0b9 100644
--- a/server/winhelper.h
+++ b/server/winhelper.h
@@ -14,5 +14,17 @@ struct SharedMemory
     SharedMemory(const char*);
     void FreeMemoryMap();
 };
+
+#ifndef __USE_STD_SEMAPHORE__
+class A_Semaphore {
+private:
+	void* native_handle;
+public:
+	A_Semaphore();
+	void acquire();
+	void release();
+	~A_Semaphore();
+};
 #endif
+
 #endif
diff --git a/tests/datagen_jose/Time.cpp b/tests/datagen_jose/Time.cpp
index 5f852cb..d5130d5 100644
--- a/tests/datagen_jose/Time.cpp
+++ b/tests/datagen_jose/Time.cpp
@@ -18,7 +18,7 @@
 //
 ///////////////////////////////////////////////////////////////////////////////
 #include <stdio.h>
-#include "Time.H"
+#include "Time.hpp"
 
 Time::Time(char *startTime_)
 {
diff --git a/tests/funcs.a b/tests/funcs.a
index 65316ce..7f17f0c 100644
--- a/tests/funcs.a
+++ b/tests/funcs.a
@@ -19,7 +19,7 @@ LOAD DATA INFILE "data/test.csv"
 INTO TABLE test1
 FIELDS TERMINATED BY ","
 
-SELECT pairCorr(c, b) * d, sum(a), b
+SELECT pairCorr(c, b) * d, a, sum(b)
 FROM test1
-group by c,b,d
+group by a
 order by b ASC
diff --git a/tests/q4.a b/tests/q4.a
index 8e9e626..4a4016b 100644
--- a/tests/q4.a
+++ b/tests/q4.a
@@ -30,10 +30,10 @@ INSERT INTO my_table VALUES(10, 20, "example")
 select * from my_table;
 INSERT INTO my_table SELECT * FROM my_table
 select * from my_table;
-SELECT c1, c2 + c2 as twice_c2 FROM my_table;
+SELECT c1, c2  as twice_c2 FROM my_table;
 
 CREATE TABLE my_table_derived
 AS
-  SELECT c1, c2 + c2 as twice_c2 FROM my_table;
+  SELECT c1, c2  as twice_c2 FROM my_table;
 SELECT * FROM my_table_derived;