diff --git a/CMakeLists.txt b/CMakeLists.txt
index ba8a752..ddd5f1a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -9,8 +9,6 @@ if (CMAKE_C_COMPILER_ID STREQUAL "MSVC")
     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} /W4 /WX")
 else()
     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -Werror")
-    add_compile_options(-fsanitize=address,undefined)
-    add_link_options(-fsanitize=address,undefined)
 endif()
 
 add_subdirectory(tests)
diff --git a/include/defs.h b/include/defs.h
index 19ef591..cc2683c 100644
--- a/include/defs.h
+++ b/include/defs.h
@@ -1,7 +1,6 @@
 //
 // Created by Seppe Degryse on 31/10/2024.
 //
-
 #ifndef DEFS_H
 #define DEFS_H
 #include <stdbool.h>
diff --git a/include/query.h b/include/query.h
index ed8837e..497576e 100644
--- a/include/query.h
+++ b/include/query.h
@@ -6,6 +6,6 @@
 #include "source.h"
 #include "defs.h"
 
-void execute_query(const query_t *query, source_t *source, sink_t *sink);
+void execute_query(const query_t *query, const source_t *source, sink_t *sink);
 
 #endif //QUERY_H
diff --git a/include/source.h b/include/source.h
index df1feb7..e4f7bc0 100644
--- a/include/source.h
+++ b/include/source.h
@@ -5,13 +5,11 @@
 #define SOURCE_H
 #include "data.h"
 
-#include <stdbool.h>
 
 // Created a source to enable other sources than generator e.g. network
 typedef struct Source {
     data_t buffer;
-    bool has_next;
-    data_t* (*get_next)(struct Source *self);
+    data_t* (*get_next)(const struct Source *self);
 } source_t;
 
 typedef struct Sink {
diff --git a/include/utils.h b/include/utils.h
index 4b9c81e..bf179df 100644
--- a/include/utils.h
+++ b/include/utils.h
@@ -9,8 +9,10 @@ static int min(const int a, const int b) {
     return a < b ? a : b;
 }
 
+/*
 static int max(const int a, const int b) {
     return a > b ? a : b;
 }
+*/
 
 #endif //UTILS_H
diff --git a/src/generator.c b/src/generator.c
index 3d23502..252cd5c 100644
--- a/src/generator.c
+++ b/src/generator.c
@@ -57,13 +57,15 @@ triple_t triples[] = {
 
 #define NUM_TRIPLES (sizeof(triples) / sizeof(triples[0]))
 
+static bool has_next = true;
 
-data_t* get_next_generator(source_t *generator) {
-    if (!generator->has_next) {
+data_t* get_next_generator(const source_t *generator) {
+    if (!has_next) {
         return NULL; // Return NULL if there are no items left
     }
-    generator->has_next = false;
-    return &generator->buffer; // Return the current buffer
+    has_next = false;
+
+    return (data_t*) &generator->buffer; // Return the current buffer
 }
 
 
@@ -71,7 +73,6 @@ source_t create_generator_source()
 {
     return (source_t) {
         .buffer = {triples, NUM_TRIPLES, 1},
-        .has_next = true,
         .get_next = get_next_generator
     };
 }
diff --git a/src/query.c b/src/query.c
index 99500d3..b3960ff 100644
--- a/src/query.c
+++ b/src/query.c
@@ -17,7 +17,7 @@
 /// @param param Join parameters containing a function ptr specifying the join condition
 void join(const data_t *in1, const data_t *in2, data_t *out, const parameter_t param)
 {
-    const uint8_t size = max(in1->size, in2->size) * (in1->width + in2->width);
+    const uint8_t size = (in1->size * in2->size) * (in1->width + in2->width);
     out->data = malloc(size * sizeof(triple_t));
     assert(out->data);
     out->size = 0;
@@ -121,10 +121,11 @@ void execute_operator(const operator_t *operator_, const data_t *in, data_t *out
 /// @param query The query to be executed
 /// @param source The source creating the input stream
 /// @param sink The sink consuming the output stream
-void execute_query(const query_t *query, source_t *source, sink_t *sink)
+void execute_query(const query_t *query, const source_t *source, sink_t *sink)
 {
     data_t data = {NULL, 0, 1};
     data_t* next_data;
+
     while ((next_data = source->get_next(source)) != NULL) {
         execute_operator(query->root, next_data, &data);
         sink->push_next(sink, &data);
diff --git a/tests/queryTests.cpp b/tests/queryTests.cpp
index 60d73ab..ca0385d 100644
--- a/tests/queryTests.cpp
+++ b/tests/queryTests.cpp
@@ -155,6 +155,48 @@ TEST_F(QueryTestFixture, test_query_filter2)
 }
 
 
+bool check_filter7(const triple_t in)
+{
+    return in.subject == SUBJECT_ALICE;
+}
+
+
+TEST_F(QueryTestFixture, test_query_filter3)
+{
+    filter_check_t conditions1[1] = {check_filter};
+    filter_check_t conditions2[1] = {check_filter2};
+    filter_check_t conditions3[1] = {check_filter7};
+    operator_t filter_op = {
+        .type = FILTER,
+        .left = nullptr,
+        .right = nullptr,
+        .params = {.filter = {.size = 1, .checks = conditions1}}
+    };
+
+    operator_t filter_op2 = {
+        .type = FILTER,
+        .left = &filter_op,
+        .right = nullptr,
+        .params = {.filter = {.size = 1, .checks = conditions2}}
+    };
+
+    operator_t filter_op3 = {
+        .type = FILTER,
+        .left = &filter_op2,
+        .right = nullptr,
+        .params = {.filter = {.size = 1, .checks = conditions3}}
+    };
+
+    query_t query_filter = {.root = &filter_op3};
+
+    execute_query(&query_filter, &gsource, &gsink);
+    triple_t expected[1] = {
+        {SUBJECT_ALICE, PREDICATE_HAS_SKILL, OBJECT_PROGRAMMING},
+    };
+    ASSERT_TRUE(ARR_EQ(gsink.buffer.data, expected, 1));
+}
+
+
 TEST_F(QueryTestFixture, test_query_window)
 {
     operator_t window_op = {