From 387936e4378f0e735705d4a589c0b6220a3b299e Mon Sep 17 00:00:00 2001
From: Hongze Cheng <hzcheng@taosdata.com>
Date: Mon, 28 Mar 2022 08:58:09 +0000
Subject: [PATCH] more TDB

---
 source/libs/tdb/src/db/tdbBtree.c  | 14 +++-----------
 source/libs/tdb/src/inc/tdbPage.h  |  1 +
 source/libs/tdb/src/page/tdbPage.c | 12 ++++++++++++
 3 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/source/libs/tdb/src/db/tdbBtree.c b/source/libs/tdb/src/db/tdbBtree.c
index faced8e839..b568de848e 100644
--- a/source/libs/tdb/src/db/tdbBtree.c
+++ b/source/libs/tdb/src/db/tdbBtree.c
@@ -30,7 +30,6 @@ struct SBTree {
   int            valLen;
   SPager        *pPager;
   FKeyComparator kcmpr;
-  u8             fanout;
   int            pageSize;
   int            maxLocal;
   int            minLocal;
@@ -100,21 +99,14 @@ int tdbBtreeOpen(int keyLen, int valLen, SPager *pPager, FKeyComparator kcmpr, S
   pBt->pPager = pPager;
   // pBt->kcmpr
   pBt->kcmpr = kcmpr ? kcmpr : tdbDefaultKeyCmprFn;
-  // pBt->fanout
-  if (keyLen == TDB_VARIANT_LEN) {
-    pBt->fanout = TDB_DEFAULT_FANOUT;
-  } else {
-    ASSERT(0);
-    // TODO: pBt->fanout = 0;
-  }
   // pBt->pageSize
   pBt->pageSize = tdbPagerGetPageSize(pPager);
   // pBt->maxLocal
-  pBt->maxLocal = (pBt->pageSize - 14) / pBt->fanout;
+  pBt->maxLocal = tdbPageCapacity(pBt->pageSize, sizeof(SIntHdr)) / 4;
   // pBt->minLocal: Should not be allowed smaller than 15, which is [nPayload][nKey][nData]
-  pBt->minLocal = (pBt->pageSize - 14) / pBt->fanout / 2;
+  pBt->minLocal = pBt->maxLocal / 2;
   // pBt->maxLeaf
-  pBt->maxLeaf = pBt->pageSize - 14;
+  pBt->maxLeaf = tdbPageCapacity(pBt->pageSize, sizeof(SLeafHdr));
   // pBt->minLeaf
   pBt->minLeaf = pBt->minLocal;
 
diff --git a/source/libs/tdb/src/inc/tdbPage.h b/source/libs/tdb/src/inc/tdbPage.h
index 49aa9f4398..563fb53e98 100644
--- a/source/libs/tdb/src/inc/tdbPage.h
+++ b/source/libs/tdb/src/inc/tdbPage.h
@@ -111,6 +111,7 @@ void tdbPageInit(SPage *pPage, u8 szAmHdr, int (*xCellSize)(const SPage *, SCell
 int  tdbPageInsertCell(SPage *pPage, int idx, SCell *pCell, int szCell, u8 asOvfl);
 int  tdbPageDropCell(SPage *pPage, int idx);
 void tdbPageCopy(SPage *pFromPage, SPage *pToPage);
+int  tdbPageCapacity(int pageSize, int amHdrSize);
 
 static inline SCell *tdbPageGetCell(SPage *pPage, int idx) {
   SCell *pCell;
diff --git a/source/libs/tdb/src/page/tdbPage.c b/source/libs/tdb/src/page/tdbPage.c
index 3301202a33..accd174e55 100644
--- a/source/libs/tdb/src/page/tdbPage.c
+++ b/source/libs/tdb/src/page/tdbPage.c
@@ -242,6 +242,18 @@ void tdbPageCopy(SPage *pFromPage, SPage *pToPage) {
   pToPage->nOverflow = pFromPage->nOverflow;
 }
 
+int tdbPageCapacity(int pageSize, int amHdrSize) {
+  int szPageHdr;
+
+  if (pageSize < 65536) {
+    szPageHdr = pageMethods.szPageHdr;
+  } else {
+    szPageHdr = pageLargeMethods.szPageHdr;
+  }
+
+  return pageSize - szPageHdr - amHdrSize;
+}
+
 static int tdbPageAllocate(SPage *pPage, int szCell, SCell **ppCell) {
   SCell *pFreeCell;
   u8    *pOffset;