diff --git a/CMakeLists.txt b/CMakeLists.txt
index fd5e12e..771d8e3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3,12 +3,12 @@ project(InvoDB)
 
 set(CMAKE_CXX_STANDARD 14)
 
-set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -O3")
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O3")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -O0")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O0")
 
 include_directories(.)
 include_directories(./invodb)
 
 add_executable(InvoDB
         invodb/main.cpp
-        invodb/main.h invodb/file/page_manager.cpp invodb/file/page_manager.h invodb/models/json.cpp invodb/models/json.h invodb/models/collection.cpp invodb/models/collection.h invodb/file/storage_page.cpp invodb/file/storage_page.h invodb/utils/logger.h invodb/utils/uuid.h invodb/btree/node.h invodb/btree/btree.h)
+        invodb/main.h invodb/file/page_manager.cpp invodb/file/page_manager.h invodb/models/collection.cpp invodb/models/collection.h invodb/file/storage_page.cpp invodb/file/storage_page.h invodb/utils/logger.h invodb/utils/uuid.h invodb/btree/node.h invodb/btree/btree.h)
diff --git a/invodb/btree/btree.h b/invodb/btree/btree.h
index e15c2aa..eb4f9b3 100644
--- a/invodb/btree/btree.h
+++ b/invodb/btree/btree.h
@@ -19,6 +19,7 @@ public:
     int getNodeSize();
     int find(const KT &key);
     int size();
+
 private:
     void removeEntry(int curAdd, const KT& key, const int& pointer);
     bool canCoalesce(int curAdd, int sibAdd);
@@ -38,11 +39,14 @@ private:
 template<int M_SIZE, typename KT, int K_SIZE>
 BTree<M_SIZE, KT, K_SIZE>::BTree(const int& address) {
     root = address;
+
     n_size = 0;
 }
 
 template<int M_SIZE, typename KT, int K_SIZE>
 void BTree<M_SIZE, KT, K_SIZE>::insert(const KT &key, const int &value) {
+
+
     if(exists(key)) {
         throw "keySet already exists.";
     }
@@ -275,6 +279,8 @@ void BTree<M_SIZE, KT, K_SIZE>::redistribute(int curAdd, int sibAdd) {
 
 template<int M_SIZE, typename KT, int K_SIZE>
 int BTree<M_SIZE, KT, K_SIZE>::findNode(const KT &key) {
+
+
     auto cur = BTreeNode<M_SIZE, KT, K_SIZE>::getNode(root);
     while(!cur->leaf) {
         for(int i=0; i<cur->size; i++) {
@@ -433,11 +439,7 @@ int BTree<M_SIZE, KT, K_SIZE>::getNodeSize() {
 
 template<int M_SIZE, typename KT, int K_SIZE>
 bool BTree<M_SIZE, KT, K_SIZE>::exists(const KT &key) {
-    auto cur = BTreeNode<M_SIZE, KT, K_SIZE>::getNode(findNode(key));
-    for(int i=0; i<cur->size; i++) {
-        if(key == cur->keySet[i]) return true;
-    }
-    return false;
+    return find(key) != -1;
 }
 
 
diff --git a/invodb/btree/node.h b/invodb/btree/node.h
index 7431150..3b5d7e3 100644
--- a/invodb/btree/node.h
+++ b/invodb/btree/node.h
@@ -83,6 +83,10 @@ BTreeNode<M_SIZE, KT, K_SIZE>::BTreeNode(const int& address): address(address) {
 
 template<int M_SIZE, typename KT, int K_SIZE>
 BTreeNode<M_SIZE, KT, K_SIZE> *BTreeNode<M_SIZE, KT, K_SIZE>::getNode(const int &address) {
+
+    std::cout << address << std::endl;
+
+
     if(address < 4) {
         throw "invalid address!";
     }
diff --git a/invodb/file/page_manager.cpp b/invodb/file/page_manager.cpp
index 1f839bb..0b79ccb 100644
--- a/invodb/file/page_manager.cpp
+++ b/invodb/file/page_manager.cpp
@@ -31,3 +31,53 @@ int PageManager::allocate() {
     setPage(index, StoragePage(index));
     return index;
 }
+
+void PageManager::release(const int &index) {
+
+}
+
+nlohmann::json PageManager::readJSONFromFile(const int &index) {
+    std::string content;
+
+    StoragePage page = getPage(index);
+    while(true) {
+        for(int i=0; i<1016; i++) {
+            if(page[i] == '\0') break;
+            content.push_back(page[i]);
+        }
+        if(page.next() == 0) break;
+        page = getPage(page.next());
+    }
+
+    return nlohmann::json::parse(content);
+}
+
+int PageManager::saveJSONToFile(const nlohmann::json& json) {
+    std::string content = json.dump();
+    int size = content.size();
+
+    StoragePage page = getPage(allocate());
+    int res = page.getAddress();
+    int p = 0;
+    while(p < size) {
+        int len = std::min(size - p, 1016);
+        page.setStartFrom(0, &content.c_str()[p], len);
+        page.save();
+        p += len;
+        if(p < size) {
+            int newPage = allocate();
+            int lastPage = page.getAddress();
+            page.setNext(newPage);
+            page.save();
+            page = getPage(newPage);
+            page.setLast(lastPage);
+            page.save();
+        }
+    }
+
+
+
+    return res;
+}
+
+
diff --git a/invodb/file/page_manager.h b/invodb/file/page_manager.h
index 859a3b1..0b3aa90 100644
--- a/invodb/file/page_manager.h
+++ b/invodb/file/page_manager.h
@@ -10,6 +10,7 @@
 #include <map>
 
 #include "storage_page.h"
+#include "json/json.hpp"
 
 class PageManager {
 public:
@@ -21,7 +22,9 @@ public:
     StoragePage getPage(const int &index);
     void setPage(const int &index, const StoragePage &page);
     int allocate();
-    void free(const int &index);
+    void release(const int &index);
+    int saveJSONToFile(const nlohmann::json& json);
+    nlohmann::json readJSONFromFile(const int &index);
 private:
     std::map<int, StoragePage> map;
     std::fstream stream;
diff --git a/invodb/file/storage_page.h b/invodb/file/storage_page.h
index b10bfed..3d563d7 100644
--- a/invodb/file/storage_page.h
+++ b/invodb/file/storage_page.h
@@ -28,7 +28,6 @@ public:
 
     double getDoubleStartFrom(const int &index);
 
-
     int *intArray();
     StoragePage(const int& id) { memset(page, 0, sizeof(page)); this->address = id; }
     char& operator[] (int index) { if(index>=1024 || index < 0) throw "overflow"; else return this->page[index]; }
diff --git a/invodb/main.cpp b/invodb/main.cpp
index 3d7dc8d..7db0050 100644
--- a/invodb/main.cpp
+++ b/invodb/main.cpp
@@ -13,7 +13,7 @@ int main() {
     srand(t);
     printf("seed: %d\n", t);
 
-    //system("rm -rf test.invodb && touch test.invodb");
+    system("rm -rf test.invodb && touch test.invodb");
 
     PageManager::loadDatabase("test.invodb");
     Collection::loadCollections();
@@ -27,12 +27,17 @@ int main() {
         Collection::createCollection("hello");
     }
 
-    JSON j;
-    j["hello"] = 1;
+    std::string test;
+    for(int i=0; i<100; i++) {
+        test += generateUUID();
+    }
+
+    nlohmann::json j;
+    j["hello"] = test;
 
     col->insert(j);
 
-    testAndBenchmark(100000);
+    //testAndBenchmark(100000);
 
     //btree->testAndBenchmark(100000);
 
diff --git a/invodb/models/collection.cpp b/invodb/models/collection.cpp
index 1f3149c..16f268f 100644
--- a/invodb/models/collection.cpp
+++ b/invodb/models/collection.cpp
@@ -6,16 +6,25 @@
 
 Collection::Collection(const std::string &name, const int &firstPage) {
     Logger::info<std::string, std::string>("load Collection: ", name);
-    tree = new BTree<27, std::string, 32>(firstPage);
+    tree = new BTree<3, std::string, 32>(firstPage);
 }
 
-void Collection::insert(JSON &json) {
-    if(json["__Invo_ID__"].empty()) {
-        json["__Invo_ID__"] = generateUUID();
+void Collection::insert(nlohmann::json &json) {
+
+    //printf("fuck:%d\n", tree);
+    if(json["__INVO_ID__"].empty()) {
+        json["__INVO_ID__"] = generateUUID();
     }
-    Logger::info<std::string, std::string>("INSERT ", json.dump());
-}
 
+    int add = PageManager::Instance().saveJSONToFile(json);
+
+    std::string id = json["__INVO_ID__"].get<std::string>();
+
+    tree->insert(id, add);
+
+    auto tjson = PageManager::Instance().readJSONFromFile(add);
+    Logger::info<std::string, std::string>("INSERT ", tjson.dump());
+}
 
 std::map<std::string, Collection*> Collection::map;
 std::set<int> Collection::free;
@@ -51,22 +60,21 @@ Collection& Collection::createCollection(const std::string &name) {
     int id = *free.begin();
     free.erase(free.begin());
 
-    printf("id: %d\n", id / 32);
     StoragePage page = PageManager::Instance().getPage(id / 32);
     id %= 32;
 
-    int collectionPage = PageManager::Instance().allocate();
+    StoragePage collectionPage = PageManager::Instance().getPage(PageManager::Instance().allocate());
 
     if(name.size() > 28) {
         throw "too long name of collection";
     }
 
     page.setStringStartFrom(id*32, name.c_str());
-    page.setIntStartFrom(id*32+28, collectionPage);
+    page.setIntStartFrom(id*32+28, collectionPage.getAddress());
     page.print();
     page.save();
 
-    Collection *col = new Collection(name, collectionPage);
+    Collection *col = new Collection(name, collectionPage.getAddress());
 
     map.insert(make_pair(name, col));
 
diff --git a/invodb/models/collection.h b/invodb/models/collection.h
index 02e5999..8d5686c 100644
--- a/invodb/models/collection.h
+++ b/invodb/models/collection.h
@@ -8,7 +8,7 @@
 #include "file/page_manager.h"
 #include "utils/logger.h"
 #include "btree/btree.h"
-#include "models/json.h"
+#include "json/json.hpp"
 #include <map>
 #include <set>
 #include <algorithm>
@@ -17,7 +17,8 @@
 
 class Collection {
 public:
-    static void insert(JSON &json);
+    void insert(nlohmann::json &json);
+
     static void loadCollections();
     static Collection& getCollection(const std::string& name);
     static Collection& createCollection(const std::string& name);
@@ -25,7 +26,7 @@ private:
     static std::map<std::string, Collection*> map;
     static std::set<int> free;
 
-    BTree<27, std::string, 32> *tree;
+    BTree<3, std::string, 32> *tree;
 
     Collection(const std::string& name,const int& firstPage);
     Collection() {}
diff --git a/invodb/models/json.cpp b/invodb/models/json.cpp
deleted file mode 100644
index b90722a..0000000
--- a/invodb/models/json.cpp
+++ /dev/null
@@ -1,5 +0,0 @@
-//
-// Created by YuhangQ on 2021/10/9.
-//
-
-#include "json.h"
diff --git a/invodb/models/json.h b/invodb/models/json.h
deleted file mode 100644
index b6e2c67..0000000
--- a/invodb/models/json.h
+++ /dev/null
@@ -1,19 +0,0 @@
-//
-// Created by YuhangQ on 2021/10/9.
-//
-
-#ifndef INVODB_JSON_H
-#define INVODB_JSON_H
-
-#include <string>
-#include "json/json.hpp"
-
-class JSON : public nlohmann::json {
-public:
-    JSON() {}
-    JSON(std::string j): nlohmann::json(j) {}
-private:
-};
-
-
-#endif //INVODB_JSON_H