enh(tdb/recycle): first round implemenation of page recycling

source/libs/tdb/src/db/tdbBtree.c

@@ -860,6 +860,9 @@ static int tdbBtreeBalanceNonRoot(SBTree *pBt, SPage *pParent, int idx, TXN *pTx
 
     if (!TDB_BTREE_PAGE_IS_LEAF(pNews[0])) {
       ((SIntHdr *)(pParent->pData))->pgno = ((SIntHdr *)(pNews[0]->pData))->pgno;
+    } else {
+      // printf("tdb/balance: btree balance delete pgno: %d.\n", TDB_PAGE_PGNO(pNews[0]));
+      tdbPagerInsertFreePage(pBt->pPager, TDB_PAGE_PGNO(pNews[0]), pTxn);
     }
   }
 
@@ -870,9 +873,15 @@ static int tdbBtreeBalanceNonRoot(SBTree *pBt, SPage *pParent, int idx, TXN *pTx
   }
 
   for (pageIdx = 0; pageIdx < nOlds; ++pageIdx) {
+    // printf("tdb/balance: btree balance old pgno: %d.\n", TDB_PAGE_PGNO(pOlds[pageIdx]));
+    if (pageIdx >= nNews) {
+      // printf("tdb/balance: btree balance delete pgno: %d.\n", TDB_PAGE_PGNO(pOlds[pageIdx]));
+      tdbPagerInsertFreePage(pBt->pPager, TDB_PAGE_PGNO(pOlds[pageIdx]), pTxn);
+    }
     tdbPagerReturnPage(pBt->pPager, pOlds[pageIdx], pTxn);
   }
   for (; pageIdx < nNews; ++pageIdx) {
+    // printf("tdb/balance: btree balance new pgno: %d.\n", TDB_PAGE_PGNO(pNews[pageIdx]));
     tdbPagerReturnPage(pBt->pPager, pNews[pageIdx], pTxn);
   }
 
@@ -2113,6 +2122,8 @@ int tdbBtcDelete(SBTC *pBtc) {
         return -1;
       }
 
+      // printf("tdb/btc-delete: btree balance delete pgno: %d.\n", TDB_PAGE_PGNO(pBtc->pPage));
+
       ret = tdbBtreeBalance(pBtc);
       if (ret < 0) {
         tdbError("tdb/btc-delete: btree balance failed with ret: %d.", ret);

source/libs/tdb/src/db/tdbDb.c

@@ -70,6 +70,11 @@ int32_t tdbOpen(const char *dbname, int32_t szPage, int32_t pages, TDB **ppDb, i
   if (ret < 0) {
     return -1;
   }
+
+  ret = tdbTbOpen(TDB_FREEDB_NAME, sizeof(SPgno), 0, NULL, pDb, &pDb->pFreeDb, rollback);
+  if (ret < 0) {
+    return -1;
+  }
 #endif
 
   *ppDb = pDb;
@@ -82,6 +87,7 @@ int tdbClose(TDB *pDb) {
   if (pDb) {
 #ifdef USE_MAINDB
     if (pDb->pMainDb) tdbTbClose(pDb->pMainDb);
+    if (pDb->pFreeDb) tdbTbClose(pDb->pFreeDb);
 #endif
 
     for (pPager = pDb->pgrList; pPager; pPager = pDb->pgrList) {

source/libs/tdb/src/db/tdbPager.c

@@ -316,6 +316,10 @@ int tdbPagerCommit(SPager *pPager, TXN *pTxn) {
       return -1;
     }
 
+    if (!TDB_PAGE_TOTAL_CELLS(pPage) && TDB_PAGE_PGNO(pPage) > 1) {
+      tdbDebug("pager/commit: %p, %d/%d, txnId:%" PRId64, pPager, pPager->dbOrigSize, pPager->dbFileSize, pTxn->txnId);
+    }
+
     ret = tdbPagerPWritePageToDB(pPager, pPage);
     if (ret < 0) {
       tdbError("failed to write page to db since %s", tstrerror(terrno));
@@ -695,9 +699,59 @@ void tdbPagerReturnPage(SPager *pPager, SPage *pPage, TXN *pTxn) {
   //        TDB_PAGE_PGNO(pPage), pPage);
 }
 
+int tdbPagerInsertFreePage(SPager *pPager, SPgno pgno, TXN *pTxn) {
+  int code = 0;
+
+  code = tdbTbInsert(pPager->pEnv->pFreeDb, &pgno, sizeof(pgno), NULL, 0, pTxn);
+  if (code < 0) {
+    return -1;
+  }
+
+  return code;
+}
+
+static int tdbPagerRemoveFreePage(SPager *pPager, SPgno *pPgno) {
+  int  code = 0;
+  TBC *pCur;
+
+  if (!pPager->pEnv->pFreeDb) {
+    return 0;
+  }
+
+  code = tdbTbcOpen(pPager->pEnv->pFreeDb, &pCur, NULL);
+  if (code < 0) {
+    return 0;
+  }
+
+  code = tdbTbcMoveToFirst(pCur);
+  if (code) {
+    tdbTbcClose(pCur);
+    return 0;
+  }
+
+  void *pKey = NULL;
+  int   nKey = 0;
+
+  code = tdbTbcGet(pCur, (const void **)&pKey, &nKey, NULL, NULL);
+  if (code < 0) {
+    tdbTbcClose(pCur);
+    return 0;
+  }
+
+  *pPgno = *(SPgno *)pKey;
+
+  code = tdbTbcDelete(pCur);
+  if (code < 0) {
+    tdbTbcClose(pCur);
+    return 0;
+  }
+  tdbTbcClose(pCur);
+  return 0;
+}
+
 static int tdbPagerAllocFreePage(SPager *pPager, SPgno *ppgno) {
   // TODO: Allocate a page from the free list
-  return 0;
+  return tdbPagerRemoveFreePage(pPager, ppgno);
 }
 
 static int tdbPagerAllocNewPage(SPager *pPager, SPgno *ppgno) {

source/libs/tdb/src/inc/tdbInt.h

@@ -198,6 +198,7 @@ int  tdbPagerAbort(SPager *pPager, TXN *pTxn);
 int  tdbPagerFetchPage(SPager *pPager, SPgno *ppgno, SPage **ppPage, int (*initPage)(SPage *, void *, int), void *arg,
                        TXN *pTxn);
 void tdbPagerReturnPage(SPager *pPager, SPage *pPage, TXN *pTxn);
+int  tdbPagerInsertFreePage(SPager *pPager, SPgno pgno, TXN *pTxn);
 int  tdbPagerAllocPage(SPager *pPager, SPgno *ppgno);
 int  tdbPagerRestoreJournals(SPager *pPager);
 int  tdbPagerRollback(SPager *pPager);
@@ -373,6 +374,7 @@ static inline SCell *tdbPageGetCell(SPage *pPage, int idx) {
 
 #ifdef USE_MAINDB
 #define TDB_MAINDB_NAME "main.tdb"
+#define TDB_FREEDB_NAME "_free.db"
 #endif
 
 struct STDB {
@@ -386,6 +388,7 @@ struct STDB {
   SPager **pgrHash;
 #ifdef USE_MAINDB
   TTB *pMainDb;
+  TTB *pFreeDb;
 #endif
   int64_t txnId;
 };

source/libs/tdb/test/CMakeLists.txt

@@ -14,3 +14,7 @@ target_link_libraries(tdbExOVFLTest tdb gtest gtest_main)
 add_executable(tdbPageDefragmentTest "tdbPageDefragmentTest.cpp")
 target_link_libraries(tdbPageDefragmentTest tdb gtest gtest_main)
 
+# page recycling testing
+add_executable(tdbPageRecycleTest "tdbPageRecycleTest.cpp")
+target_link_libraries(tdbPageRecycleTest tdb gtest gtest_main)
+

source/libs/tdb/test/tdbPageRecycleTest.cpp

+#include <gtest/gtest.h>
+
+#define ALLOW_FORBID_FUNC
+#include "os.h"
+#include "tdb.h"
+
+#include <shared_mutex>
+#include <string>
+#include <thread>
+#include <vector>
+#include "tlog.h"
+
+typedef struct SPoolMem {
+  int64_t          size;
+  struct SPoolMem *prev;
+  struct SPoolMem *next;
+} SPoolMem;
+
+static SPoolMem *openPool() {
+  SPoolMem *pPool = (SPoolMem *)taosMemoryMalloc(sizeof(*pPool));
+
+  pPool->prev = pPool->next = pPool;
+  pPool->size = 0;
+
+  return pPool;
+}
+
+static void clearPool(SPoolMem *pPool) {
+  SPoolMem *pMem;
+
+  do {
+    pMem = pPool->next;
+
+    if (pMem == pPool) break;
+
+    pMem->next->prev = pMem->prev;
+    pMem->prev->next = pMem->next;
+    pPool->size -= pMem->size;
+
+    taosMemoryFree(pMem);
+  } while (1);
+
+  assert(pPool->size == 0);
+}
+
+static void closePool(SPoolMem *pPool) {
+  clearPool(pPool);
+  taosMemoryFree(pPool);
+}
+
+static void *poolMalloc(void *arg, size_t size) {
+  void     *ptr = NULL;
+  SPoolMem *pPool = (SPoolMem *)arg;
+  SPoolMem *pMem;
+
+  pMem = (SPoolMem *)taosMemoryMalloc(sizeof(*pMem) + size);
+  if (pMem == NULL) {
+    assert(0);
+  }
+
+  pMem->size = sizeof(*pMem) + size;
+  pMem->next = pPool->next;
+  pMem->prev = pPool;
+
+  pPool->next->prev = pMem;
+  pPool->next = pMem;
+  pPool->size += pMem->size;
+
+  ptr = (void *)(&pMem[1]);
+  return ptr;
+}
+
+static void poolFree(void *arg, void *ptr) {
+  SPoolMem *pPool = (SPoolMem *)arg;
+  SPoolMem *pMem;
+
+  pMem = &(((SPoolMem *)ptr)[-1]);
+
+  pMem->next->prev = pMem->prev;
+  pMem->prev->next = pMem->next;
+  pPool->size -= pMem->size;
+
+  taosMemoryFree(pMem);
+}
+
+static int tKeyCmpr(const void *pKey1, int kLen1, const void *pKey2, int kLen2) {
+  int k1, k2;
+
+  std::string s1((char *)pKey1 + 3, kLen1 - 3);
+  std::string s2((char *)pKey2 + 3, kLen2 - 3);
+  k1 = stoi(s1);
+  k2 = stoi(s2);
+
+  if (k1 < k2) {
+    return -1;
+  } else if (k1 > k2) {
+    return 1;
+  } else {
+    return 0;
+  }
+}
+
+static int tDefaultKeyCmpr(const void *pKey1, int keyLen1, const void *pKey2, int keyLen2) {
+  int mlen;
+  int cret;
+
+  ASSERT(keyLen1 > 0 && keyLen2 > 0 && pKey1 != NULL && pKey2 != NULL);
+
+  mlen = keyLen1 < keyLen2 ? keyLen1 : keyLen2;
+  cret = memcmp(pKey1, pKey2, mlen);
+  if (cret == 0) {
+    if (keyLen1 < keyLen2) {
+      cret = -1;
+    } else if (keyLen1 > keyLen2) {
+      cret = 1;
+    } else {
+      cret = 0;
+    }
+  }
+  return cret;
+}
+
+static void generateBigVal(char *val, int valLen) {
+  for (int i = 0; i < valLen; ++i) {
+    char c = char(i & 0xff);
+    if (c == 0) {
+      c = 1;
+    }
+    val[i] = c;
+  }
+}
+
+static TDB *openEnv(char const *envName, int const pageSize, int const pageNum) {
+  TDB *pEnv = NULL;
+
+  int ret = tdbOpen(envName, pageSize, pageNum, &pEnv, 0);
+  if (ret) {
+    pEnv = NULL;
+  }
+
+  return pEnv;
+}
+
+static void insertOfp(void) {
+  int ret = 0;
+
+  taosRemoveDir("tdb");
+
+  // open Env
+  int const pageSize = 4096;
+  int const pageNum = 64;
+  TDB      *pEnv = openEnv("tdb", pageSize, pageNum);
+  GTEST_ASSERT_NE(pEnv, nullptr);
+
+  // open db
+  TTB          *pDb = NULL;
+  tdb_cmpr_fn_t compFunc = tKeyCmpr;
+  // ret = tdbTbOpen("ofp_insert.db", -1, -1, compFunc, pEnv, &pDb, 0);
+  ret = tdbTbOpen("ofp_insert.db", 12, -1, compFunc, pEnv, &pDb, 0);
+  GTEST_ASSERT_EQ(ret, 0);
+
+  // open the pool
+  SPoolMem *pPool = openPool();
+
+  // start a transaction
+  TXN *txn = NULL;
+
+  tdbBegin(pEnv, &txn, poolMalloc, poolFree, pPool, TDB_TXN_WRITE | TDB_TXN_READ_UNCOMMITTED);
+
+  // generate value payload
+  // char val[((4083 - 4 - 3 - 2) + 1) * 100];  // pSize(4096) - amSize(1) - pageHdr(8) - footerSize(4)
+  char val[32605];
+  int  valLen = sizeof(val) / sizeof(val[0]);
+  generateBigVal(val, valLen);
+
+  // insert the generated big data
+  // char const *key = "key1";
+  char const *key = "key123456789";
+  ret = tdbTbInsert(pDb, key, strlen(key), val, valLen, txn);
+  GTEST_ASSERT_EQ(ret, 0);
+
+  // commit current transaction
+  tdbCommit(pEnv, txn);
+  tdbPostCommit(pEnv, txn);
+}
+
+TEST(TdbPageRecycleTest, DISABLED_TbInsertTest) {
+  // TEST(TdbPageRecycleTest, TbInsertTest) {
+  // ofp inserting
+  insertOfp();
+}
+
+TEST(TdbPageRecycleTest, DISABLED_TbGetTest) {
+  // TEST(TdbPageRecycleTest, TbGetTest) {
+  insertOfp();
+
+  // open Env
+  int const pageSize = 4096;
+  int const pageNum = 64;
+  TDB      *pEnv = openEnv("tdb", pageSize, pageNum);
+  GTEST_ASSERT_NE(pEnv, nullptr);
+
+  // open db
+  TTB          *pDb = NULL;
+  tdb_cmpr_fn_t compFunc = tKeyCmpr;
+  // int           ret = tdbTbOpen("ofp_insert.db", -1, -1, compFunc, pEnv, &pDb, 0);
+  int ret = tdbTbOpen("ofp_insert.db", 12, -1, compFunc, pEnv, &pDb, 0);
+  GTEST_ASSERT_EQ(ret, 0);
+
+  // generate value payload
+  // char val[((4083 - 4 - 3 - 2) + 1) * 100];  // pSize(4096) - amSize(1) - pageHdr(8) - footerSize(4)
+  char val[32605];
+  int  valLen = sizeof(val) / sizeof(val[0]);
+  generateBigVal(val, valLen);
+
+  {  // Query the data
+    void *pVal = NULL;
+    int   vLen;
+
+    // char const *key = "key1";
+    char const *key = "key123456789";
+    ret = tdbTbGet(pDb, key, strlen(key), &pVal, &vLen);
+    ASSERT(ret == 0);
+    GTEST_ASSERT_EQ(ret, 0);
+
+    GTEST_ASSERT_EQ(vLen, valLen);
+    GTEST_ASSERT_EQ(memcmp(val, pVal, vLen), 0);
+
+    tdbFree(pVal);
+  }
+}
+
+TEST(TdbPageRecycleTest, DISABLED_TbDeleteTest) {
+  // TEST(TdbPageRecycleTest, TbDeleteTest) {
+  int ret = 0;
+
+  taosRemoveDir("tdb");
+
+  // open Env
+  int const pageSize = 4096;
+  int const pageNum = 64;
+  TDB      *pEnv = openEnv("tdb", pageSize, pageNum);
+  GTEST_ASSERT_NE(pEnv, nullptr);
+
+  // open db
+  TTB          *pDb = NULL;
+  tdb_cmpr_fn_t compFunc = tKeyCmpr;
+  ret = tdbTbOpen("ofp_insert.db", -1, -1, compFunc, pEnv, &pDb, 0);
+  GTEST_ASSERT_EQ(ret, 0);
+
+  // open the pool
+  SPoolMem *pPool = openPool();
+
+  // start a transaction
+  TXN *txn;
+
+  tdbBegin(pEnv, &txn, poolMalloc, poolFree, pPool, TDB_TXN_WRITE | TDB_TXN_READ_UNCOMMITTED);
+
+  // generate value payload
+  // char val[((4083 - 4 - 3 - 2) + 1) * 100];  // pSize(4096) - amSize(1) - pageHdr(8) - footerSize(4)
+  char val[((4083 - 4 - 3 - 2) + 1) * 2];  // pSize(4096) - amSize(1) - pageHdr(8) - footerSize(4)
+  int  valLen = sizeof(val) / sizeof(val[0]);
+  generateBigVal(val, valLen);
+
+  {  // insert the generated big data
+    ret = tdbTbInsert(pDb, "key1", strlen("key1"), val, valLen, txn);
+    GTEST_ASSERT_EQ(ret, 0);
+  }
+
+  {  // query the data
+    void *pVal = NULL;
+    int   vLen;
+
+    ret = tdbTbGet(pDb, "key1", strlen("key1"), &pVal, &vLen);
+    ASSERT(ret == 0);
+    GTEST_ASSERT_EQ(ret, 0);
+
+    GTEST_ASSERT_EQ(vLen, valLen);
+    GTEST_ASSERT_EQ(memcmp(val, pVal, vLen), 0);
+
+    tdbFree(pVal);
+  }
+  /* open to debug committed file
+tdbCommit(pEnv, &txn);
+tdbTxnClose(&txn);
+
+++txnid;
+tdbTxnOpen(&txn, txnid, poolMalloc, poolFree, pPool, TDB_TXN_WRITE | TDB_TXN_READ_UNCOMMITTED);
+tdbBegin(pEnv, &txn);
+  */
+  {  // upsert the data
+    ret = tdbTbUpsert(pDb, "key1", strlen("key1"), "value1", strlen("value1"), txn);
+    GTEST_ASSERT_EQ(ret, 0);
+  }
+
+  {  // query the upserted data
+    void *pVal = NULL;
+    int   vLen;
+
+    ret = tdbTbGet(pDb, "key1", strlen("key1"), &pVal, &vLen);
+    ASSERT(ret == 0);
+    GTEST_ASSERT_EQ(ret, 0);
+
+    GTEST_ASSERT_EQ(vLen, strlen("value1"));
+    GTEST_ASSERT_EQ(memcmp("value1", pVal, vLen), 0);
+
+    tdbFree(pVal);
+  }
+
+  {  // delete the data
+    ret = tdbTbDelete(pDb, "key1", strlen("key1"), txn);
+    GTEST_ASSERT_EQ(ret, 0);
+  }
+
+  {  // query the deleted data
+    void *pVal = NULL;
+    int   vLen = -1;
+
+    ret = tdbTbGet(pDb, "key1", strlen("key1"), &pVal, &vLen);
+    ASSERT(ret == -1);
+    GTEST_ASSERT_EQ(ret, -1);
+
+    GTEST_ASSERT_EQ(vLen, -1);
+    GTEST_ASSERT_EQ(pVal, nullptr);
+
+    tdbFree(pVal);
+  }
+
+  // commit current transaction
+  tdbCommit(pEnv, txn);
+  tdbPostCommit(pEnv, txn);
+}
+
+TEST(TdbPageRecycleTest, DISABLED_simple_insert1) {
+  // TEST(TdbPageRecycleTest, simple_insert1) {
+  int           ret;
+  TDB          *pEnv;
+  TTB          *pDb;
+  tdb_cmpr_fn_t compFunc;
+  int           nData = 1;
+  TXN          *txn;
+  int const     pageSize = 4096;
+
+  taosRemoveDir("tdb");
+
+  // Open Env
+  ret = tdbOpen("tdb", pageSize, 64, &pEnv, 0);
+  GTEST_ASSERT_EQ(ret, 0);
+
+  // Create a database
+  compFunc = tKeyCmpr;
+  ret = tdbTbOpen("db.db", -1, -1, compFunc, pEnv, &pDb, 0);
+  GTEST_ASSERT_EQ(ret, 0);
+
+  {
+    char key[64];
+    // char      val[(4083 - 4 - 3 - 2)]; // pSize(4096) - amSize(1) - pageHdr(8) - footerSize(4)
+    char      val[(4083 - 4 - 3 - 2) + 1];  // pSize(4096) - amSize(1) - pageHdr(8) - footerSize(4)
+    int64_t   poolLimit = 4096;             // 1M pool limit
+    SPoolMem *pPool;
+
+    // open the pool
+    pPool = openPool();
+
+    // start a transaction
+    tdbBegin(pEnv, &txn, poolMalloc, poolFree, pPool, TDB_TXN_WRITE | TDB_TXN_READ_UNCOMMITTED);
+
+    for (int iData = 1; iData <= nData; iData++) {
+      sprintf(key, "key0");
+      sprintf(val, "value%d", iData);
+
+      // ret = tdbTbInsert(pDb, key, strlen(key), val, strlen(val), &txn);
+      // GTEST_ASSERT_EQ(ret, 0);
+
+      // generate value payload
+      int valLen = sizeof(val) / sizeof(val[0]);
+      for (int i = 6; i < valLen; ++i) {
+        char c = char(i & 0xff);
+        if (c == 0) {
+          c = 1;
+        }
+        val[i] = c;
+      }
+
+      ret = tdbTbInsert(pDb, "key1", strlen("key1"), val, valLen, txn);
+      GTEST_ASSERT_EQ(ret, 0);
+
+      // if pool is full, commit the transaction and start a new one
+      if (pPool->size >= poolLimit) {
+        // commit current transaction
+        tdbCommit(pEnv, txn);
+        tdbPostCommit(pEnv, txn);
+
+        // start a new transaction
+        clearPool(pPool);
+
+        tdbBegin(pEnv, &txn, poolMalloc, poolFree, pPool, TDB_TXN_WRITE | TDB_TXN_READ_UNCOMMITTED);
+      }
+    }
+
+    // commit the transaction
+    tdbCommit(pEnv, txn);
+    tdbPostCommit(pEnv, txn);
+
+    {  // Query the data
+      void *pVal = NULL;
+      int   vLen;
+
+      for (int i = 1; i <= nData; i++) {
+        sprintf(key, "key%d", i);
+        // sprintf(val, "value%d", i);
+
+        ret = tdbTbGet(pDb, key, strlen(key), &pVal, &vLen);
+        ASSERT(ret == 0);
+        GTEST_ASSERT_EQ(ret, 0);
+
+        GTEST_ASSERT_EQ(vLen, sizeof(val) / sizeof(val[0]));
+        GTEST_ASSERT_EQ(memcmp(val, pVal, vLen), 0);
+      }
+
+      tdbFree(pVal);
+    }
+
+    {  // Iterate to query the DB data
+      TBC  *pDBC;
+      void *pKey = NULL;
+      void *pVal = NULL;
+      int   vLen, kLen;
+      int   count = 0;
+
+      ret = tdbTbcOpen(pDb, &pDBC, NULL);
+      GTEST_ASSERT_EQ(ret, 0);
+
+      tdbTbcMoveToFirst(pDBC);
+
+      for (;;) {
+        ret = tdbTbcNext(pDBC, &pKey, &kLen, &pVal, &vLen);
+        if (ret < 0) break;
+
+        // std::cout.write((char *)pKey, kLen) /* << " " << kLen */ << " ";
+        // std::cout.write((char *)pVal, vLen) /* << " " << vLen */;
+        // std::cout << std::endl;
+
+        count++;
+      }
+
+      GTEST_ASSERT_EQ(count, nData);
+
+      tdbTbcClose(pDBC);
+
+      tdbFree(pKey);
+      tdbFree(pVal);
+    }
+  }
+
+  ret = tdbTbDrop(pDb);
+  GTEST_ASSERT_EQ(ret, 0);
+
+  // Close a database
+  tdbTbClose(pDb);
+
+  // Close Env
+  ret = tdbClose(pEnv);
+  GTEST_ASSERT_EQ(ret, 0);
+}
+
+// TEST(TdbPageRecycleTest, DISABLED_seq_insert) {
+TEST(TdbPageRecycleTest, seq_insert) {
+  int           ret = 0;
+  TDB          *pEnv = NULL;
+  TTB          *pDb = NULL;
+  tdb_cmpr_fn_t compFunc;
+  int           nData = 256;
+  TXN          *txn = NULL;
+  int const     pageSize = 4 * 1024;
+
+  taosRemoveDir("tdb");
+
+  // Open Env
+  ret = tdbOpen("tdb", pageSize, 64, &pEnv, 0);
+  GTEST_ASSERT_EQ(ret, 0);
+
+  // Create a database
+  compFunc = tKeyCmpr;
+  ret = tdbTbOpen("db.db", -1, -1, compFunc, pEnv, &pDb, 0);
+  GTEST_ASSERT_EQ(ret, 0);
+
+  // 1, insert nData kv
+  {
+    char      key[64];
+    char      val[(4083 - 4 - 3 - 2) + 1];  // pSize(4096) - amSize(1) - pageHdr(8) - footerSize(4)
+    int64_t   poolLimit = 4096;             // 1M pool limit
+    SPoolMem *pPool;
+
+    // open the pool
+    pPool = openPool();
+
+    // start a transaction
+    tdbBegin(pEnv, &txn, poolMalloc, poolFree, pPool, TDB_TXN_WRITE | TDB_TXN_READ_UNCOMMITTED);
+
+    for (int iData = 0; iData < nData; ++iData) {
+      sprintf(key, "key%03d", iData);
+      sprintf(val, "value%03d", iData);
+
+      ret = tdbTbInsert(pDb, key, strlen(key), val, strlen(val), txn);
+      GTEST_ASSERT_EQ(ret, 0);
+      // if pool is full, commit the transaction and start a new one
+      if (pPool->size >= poolLimit) {
+        // commit current transaction
+        tdbCommit(pEnv, txn);
+        tdbPostCommit(pEnv, txn);
+
+        // start a new transaction
+        clearPool(pPool);
+
+        tdbBegin(pEnv, &txn, poolMalloc, poolFree, pPool, TDB_TXN_WRITE | TDB_TXN_READ_UNCOMMITTED);
+      }
+    }
+
+    // commit the transaction
+    tdbCommit(pEnv, txn);
+    tdbPostCommit(pEnv, txn);
+
+    // 2, delete nData/2 records
+
+    closePool(pPool);
+  }
+
+  // Close a database
+  tdbTbClose(pDb);
+
+  // Close Env
+  ret = tdbClose(pEnv);
+  GTEST_ASSERT_EQ(ret, 0);
+
+  system("ls -l ./tdb");
+}
+
+// TEST(TdbPageRecycleTest, DISABLED_seq_delete) {
+TEST(TdbPageRecycleTest, seq_delete) {
+  int           ret = 0;
+  TDB          *pEnv = NULL;
+  TTB          *pDb = NULL;
+  tdb_cmpr_fn_t compFunc;
+  int           nData = 256;
+  TXN          *txn = NULL;
+  int const     pageSize = 4 * 1024;
+
+  // Open Env
+  ret = tdbOpen("tdb", pageSize, 64, &pEnv, 0);
+  GTEST_ASSERT_EQ(ret, 0);
+
+  // Create a database
+  compFunc = tKeyCmpr;
+  ret = tdbTbOpen("db.db", -1, -1, compFunc, pEnv, &pDb, 0);
+  GTEST_ASSERT_EQ(ret, 0);
+
+  // 2, delete nData/2 records
+  {
+    char      key[64];
+    char      val[(4083 - 4 - 3 - 2) + 1];  // pSize(4096) - amSize(1) - pageHdr(8) - footerSize(4)
+    int64_t   poolLimit = 4096;             // 1M pool limit
+    SPoolMem *pPool;
+
+    // open the pool
+    pPool = openPool();
+
+    // start a transaction
+    tdbBegin(pEnv, &txn, poolMalloc, poolFree, pPool, TDB_TXN_WRITE | TDB_TXN_READ_UNCOMMITTED);
+
+    for (int iData = 0; iData < nData; iData++) {
+      // if (iData % 2 == 0) continue;
+
+      sprintf(key, "key%03d", iData);
+      sprintf(val, "value%03d", iData);
+
+      {  // delete the data
+        ret = tdbTbDelete(pDb, key, strlen(key), txn);
+        GTEST_ASSERT_EQ(ret, 0);
+      }
+      // if pool is full, commit the transaction and start a new one
+      if (pPool->size >= poolLimit) {
+        // commit current transaction
+        tdbCommit(pEnv, txn);
+        tdbPostCommit(pEnv, txn);
+
+        // start a new transaction
+        clearPool(pPool);
+
+        tdbBegin(pEnv, &txn, poolMalloc, poolFree, pPool, TDB_TXN_WRITE | TDB_TXN_READ_UNCOMMITTED);
+      }
+    }
+
+    // commit the transaction
+    tdbCommit(pEnv, txn);
+    tdbPostCommit(pEnv, txn);
+
+    closePool(pPool);
+  }
+
+  // Close a database
+  tdbTbClose(pDb);
+
+  // Close Env
+  ret = tdbClose(pEnv);
+  GTEST_ASSERT_EQ(ret, 0);
+
+  system("ls -l ./tdb");
+}
+
+// TEST(TdbPageRecycleTest, DISABLED_recycly_insert) {
+TEST(TdbPageRecycleTest, recycly_insert) {
+  int           ret = 0;
+  TDB          *pEnv = NULL;
+  TTB          *pDb = NULL;
+  tdb_cmpr_fn_t compFunc = tKeyCmpr;
+  int           nData = 256;
+  TXN          *txn = NULL;
+  int const     pageSize = 4 * 1024;
+
+  // Open Env
+  ret = tdbOpen("tdb", pageSize, 64, &pEnv, 0);
+  GTEST_ASSERT_EQ(ret, 0);
+
+  // Create a database
+  ret = tdbTbOpen("db.db", -1, -1, compFunc, pEnv, &pDb, 0);
+  GTEST_ASSERT_EQ(ret, 0);
+
+  // 3, insert 32k records
+  {
+    char      key[64];
+    char      val[(4083 - 4 - 3 - 2) + 1];  // pSize(4096) - amSize(1) - pageHdr(8) - footerSize(4)
+    int64_t   poolLimit = 4096;
+    SPoolMem *pPool;
+
+    // open the pool
+    pPool = openPool();
+
+    // start a transaction
+    tdbBegin(pEnv, &txn, poolMalloc, poolFree, pPool, TDB_TXN_WRITE | TDB_TXN_READ_UNCOMMITTED);
+
+    for (int iData = nData; iData < nData + nData; iData++) {
+      sprintf(key, "key%03d", iData);
+      sprintf(val, "value%03d", iData);
+
+      ret = tdbTbInsert(pDb, key, strlen(key), val, strlen(val), txn);
+      GTEST_ASSERT_EQ(ret, 0);
+
+      if (pPool->size >= poolLimit) {
+        tdbCommit(pEnv, txn);
+        tdbPostCommit(pEnv, txn);
+
+        // start a new transaction
+        clearPool(pPool);
+
+        tdbBegin(pEnv, &txn, poolMalloc, poolFree, pPool, TDB_TXN_WRITE | TDB_TXN_READ_UNCOMMITTED);
+      }
+    }
+
+    tdbCommit(pEnv, txn);
+    tdbPostCommit(pEnv, txn);
+
+    closePool(pPool);
+  }
+
+  // Close a database
+  tdbTbClose(pDb);
+
+  // Close Env
+  ret = tdbClose(pEnv);
+  GTEST_ASSERT_EQ(ret, 0);
+
+  system("ls -l ./tdb");
+}