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IX_Manager.cpp
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IX_Manager.cpp
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//
// File: IX_Manager.cpp
// Description: Implementation for IX_Manager
// Authors: dim dew
//
#include "stdafx.h"
#include "IX_Manager.h"
#include <cassert>
#include <iostream>
int IXComp(IX_IndexHandle* indexHandle, void* ldata, void* rdata, int llen, int rlen)
{
switch (indexHandle->fileHeader.attrType) {
case chars:
{
char* l = (char*)ldata;
char* r = (char*)rdata;
int min_len = MIN(llen, rlen);
int cmp_res = strncmp(l, r, min_len);
if (cmp_res == 0)
cmp_res = (llen > rlen) ? 1 : (llen == rlen) ? 0 : -1;
return cmp_res;
}
case ints:
{
int l = *(int*)ldata;
int r = *(int*)rdata;
return (l > r) ? 1 : (l == r) ? 0 : -1;
}
case floats:
{
float l = *(float*)ldata;
float r = *(float*)rdata;
return (l > r) ? 1 : (l == r) ? 0 : -1;
}
}
}
bool innerCmp(IX_IndexScan* indexScan, char* data)
{
int attrLen = indexScan->pIXIndexHandle->fileHeader.attrLength;
int cmpres = IXComp(indexScan->pIXIndexHandle, data, indexScan->value, attrLen, attrLen);
switch (indexScan->compOp)
{
case EQual:
return cmpres == 0;
case LEqual:
return cmpres <= 0;
case NEqual:
return cmpres != 0;
case LessT:
return cmpres < 0;
case GEqual:
return cmpres >= 0;
case GreatT:
return cmpres > 0;
case NO_OP:
return true;
}
}
bool ridEqual(const RID* lrid, const RID* rrid)
{
return (lrid->pageNum == rrid->pageNum && lrid->slotNum == rrid->slotNum);
}
RC OpenIndexScan(IX_IndexScan* indexScan, IX_IndexHandle* indexHandle, CompOp compOp, char* value)
{
RC rc;
PF_PageHandle pfPageHandle;
memset(indexScan, 0, sizeof(IX_IndexScan));
if (indexScan->bOpen)
return IX_SCANOPENNED;
if (!(indexHandle->bOpen))
return IX_IHCLOSED;
indexScan->bOpen = true;
indexScan->compOp = compOp;
indexScan->pIXIndexHandle = indexHandle;
indexScan->value = value;
indexScan->inBucket = false;
if (rc = SearchEntry(indexHandle, indexScan->value, &(indexScan->pnNext), &(indexScan->ridIx)))
return rc;
// 因为重复键值的处理使用的是bucket Page
// 虽然查找的是最大的小于等于目标值的位置
// 但是只需要自增1即可移到最小的大于目标值的位置
switch (indexScan->compOp) {
case LEqual:
case NEqual:
case LessT:
case NO_OP:
{
indexScan->pnNext = indexHandle->fileHeader.first_leaf;
indexScan->ridIx = 0;
break;
}
case GreatT:
{
char* data;
if ((rc = GetThisPage(&(indexHandle->fileHandle), indexScan->pnNext, &pfPageHandle)) ||
(rc = GetData(&pfPageHandle, &data)))
return rc;
IX_NodePageHeader* nodeHdr = (IX_NodePageHeader*)data;
indexScan->ridIx++;
if (indexScan->ridIx >= nodeHdr->keynum) {
indexScan->pnNext = nodeHdr->sibling;
indexScan->ridIx = 0;
}
if (rc = UnpinPage(&pfPageHandle))
return rc;
break;
}
default:
break;
}
return SUCCESS;
}
RC setRidGetNextInBucket(IX_IndexScan* indexScan, RID* rid, IX_NodePageHeader* nodePageHdr)
{
RC rc;
PF_PageHandle bucketPage;
char* data;
if ((rc = GetThisPage(&(indexScan->pIXIndexHandle->fileHandle), indexScan->nextBucketPage, &bucketPage)) ||
(rc = GetData(&bucketPage, &data)))
return rc;
IX_BucketPageHeader* bucketPageHdr = (IX_BucketPageHeader*)data;
IX_BucketEntry* bucketEntry = (IX_BucketEntry*)(data + indexScan->pIXIndexHandle->fileHeader.bucketEntryListOffset);
if (indexScan->nextBucketSlot == IX_I_DONT_KNOW_BUCKET_SLOT)
indexScan->nextBucketSlot = bucketPageHdr->firstValidSlot;
*rid = bucketEntry[indexScan->nextBucketSlot].rid;
if (bucketEntry[indexScan->nextBucketSlot].nextFreeSlot == IX_NO_MORE_BUCKET_SLOT) {
// 当前页没有可用slot了
if (bucketPageHdr->nextBucket != IX_NO_MORE_BUCKET_PAGE) {
// 还有下一页
indexScan->nextBucketPage = bucketPageHdr->nextBucket;
PF_PageHandle nextBucketPage;
if ((rc = GetThisPage(&(indexScan->pIXIndexHandle->fileHandle), indexScan->nextBucketPage, &nextBucketPage)) ||
(rc = GetData(&nextBucketPage, &data)))
return rc;
IX_BucketPageHeader* nextBucketPageHdr = (IX_BucketPageHeader*)data;
indexScan->nextBucketSlot = nextBucketPageHdr->firstValidSlot;
if (rc = UnpinPage(&nextBucketPage))
return rc;
}
else {
// 没有了
indexScan->inBucket = false;
indexScan->ridIx++;
if (indexScan->ridIx >= nodePageHdr->keynum) {
indexScan->pnNext = nodePageHdr->sibling;
indexScan->ridIx = 0;
}
}
}
else {
// 当前页还有可用slot
indexScan->nextBucketSlot = bucketEntry[indexScan->nextBucketSlot].nextFreeSlot;
}
if (rc = UnpinPage(&bucketPage))
return rc;
return SUCCESS;
}
RC IX_GetNextEntry(IX_IndexScan* indexScan, RID* rid)
{
RC rc;
char* data, *key, *curKey;
PF_PageHandle pageHandle;
IX_NodePageHeader* nodePageHdr;
IX_NodeEntry* nodeEntry;
int attrLen = indexScan->pIXIndexHandle->fileHeader.attrLength;
if (indexScan->pnNext == IX_NO_MORE_NEXT_LEAF) {
return IX_EOF;
}
if ((rc = GetThisPage(&(indexScan->pIXIndexHandle->fileHandle), indexScan->pnNext, &pageHandle)) ||
(rc = GetData(&pageHandle, &data)))
return rc;
nodePageHdr = (IX_NodePageHeader*)data;
key = data + (indexScan->pIXIndexHandle->fileHeader.nodeKeyListOffset);
nodeEntry = (IX_NodeEntry*)(data + (indexScan->pIXIndexHandle->fileHeader.nodeEntryListOffset));
curKey = key + (attrLen * (indexScan->ridIx));
if (indexScan->inBucket) {
if ((rc = setRidGetNextInBucket(indexScan, rid, nodePageHdr)) ||
(rc = UnpinPage(&pageHandle)))
return rc;
return SUCCESS;
}
// 扫描 leaf 节点状态
bool cmpres = innerCmp(indexScan, curKey);
switch (indexScan->compOp)
{
case LEqual:
case EQual:
case LessT:
{
if (!cmpres) {
if (rc = UnpinPage(&pageHandle))
return rc;
return IX_EOF;
}
break;
}
case NEqual:
{
if (!cmpres) {
indexScan->ridIx++;
if (indexScan->ridIx >= nodePageHdr->keynum) {
indexScan->pnNext = nodePageHdr->sibling;
indexScan->ridIx = 0;
// 重新获得新的 page
if (indexScan->pnNext == IX_NO_MORE_NEXT_LEAF)
return IX_EOF;
if ((rc = UnpinPage(&pageHandle)) ||
(rc = GetThisPage(&(indexScan->pIXIndexHandle->fileHandle), indexScan->pnNext, &pageHandle)) ||
(rc = GetData(&pageHandle, &data)))
return rc;
nodePageHdr = (IX_NodePageHeader*)data;
key = data + (indexScan->pIXIndexHandle->fileHeader.nodeKeyListOffset);
nodeEntry = (IX_NodeEntry*)(data + (indexScan->pIXIndexHandle->fileHeader.nodeEntryListOffset));
}
}
break;
}
default:
break;
}
if (nodeEntry[indexScan->ridIx].tag == DUP) {
indexScan->inBucket = true;
indexScan->nextBucketPage = nodeEntry[indexScan->ridIx].rid.pageNum;
indexScan->nextBucketSlot = IX_I_DONT_KNOW_BUCKET_SLOT;
if (rc = setRidGetNextInBucket(indexScan, rid, nodePageHdr))
return rc;
} else {
*rid = nodeEntry[indexScan->ridIx].rid;
indexScan->ridIx++;
if (indexScan->ridIx >= nodePageHdr->keynum) {
indexScan->pnNext = nodePageHdr->sibling;
indexScan->ridIx = 0;
}
}
if (rc = UnpinPage(&pageHandle))
return rc;
return SUCCESS;
}
RC CloseIndexScan(IX_IndexScan* indexScan)
{
RC rc;
if (!(indexScan->bOpen))
return IX_ISCLOSED;
indexScan->bOpen = false;
return SUCCESS;
}
//RC GetIndexTree(char *fileName, Tree *index){
// return SUCCESS;
//}
//
// 目的: 创建一个 Index File，
// 该 Index File 基于 长度为 attrlength 类型为 attrType 的 key
// 实现非常类似 RM_Manager 中的 CreateFile
// 1. 计算出一个 Page 中能够存放的 key entry 结构的数量，或者说初始化 B+树 的 order
// 2. 调用 PF_Manager::CreateFile() 将 Paged File 的相关控制信息进行初始化
// 3. 调用 PF_Manager::OpenFile() 打开该文件 获取 PF_FileHandle
// 4. 通过该 PF_FileHandle 的 AllocatePage 方法申请内存缓冲区 拿到第 1 页的 pData 指针
// 5. 初始化一个 IX_FileHdr 结构，写到 pData 指向的内存区
// 6. 通过该 PF_FileHandle 的 AllocatePage 方法申请内存缓冲区 拿到第 2 页的 pData 指针
// 7. 初始化一个 IX_NodeHdr 结构，写到 pData 指向的内存区, 初始化一个空的 Root 节点
// 6. 标记 第 1，2 页 为脏
// 7. PF_Manager::CloseFile() 将调用 ForceAllPage
//
RC CreateIndex(const char* fileName, AttrType attrType, int attrLength)
{
std::cout << "Bucket Entry Size: " << sizeof(IX_BucketEntry) << std::endl;
std::cout << "Node Entry Size: " << sizeof(IX_NodeEntry) << std::endl;
int maxKeysNum, maxBucketEntryNum;
RC rc;
PF_FileHandle pfFileHandle;
PF_PageHandle pfHdrPage, pfFirstRootPage;
char* fileHdrData, * nodeHdrData;
IX_FileHeader* ixFileHdr;
IX_NodePageHeader* ixNodeHdr;
// B+树 最小 order 需要为 3， split情况下至少要在一个 node 中存下 3条 key记录
maxKeysNum = (PF_PAGE_SIZE - sizeof(IX_NodePageHeader))
/ (sizeof(IX_NodeEntry) + attrLength);
maxBucketEntryNum = (PF_PAGE_SIZE - sizeof(IX_BucketPageHeader)) / sizeof(IX_BucketEntry);
if (maxKeysNum < 3)
return IX_INVALIDKEYSIZE;
// 2. 调用 PF_Manager::CreateFile() 将 Paged File 的相关控制信息进行初始化
// 3. 调用 PF_Manager::OpenFile() 打开该文件 获取 PF_FileHandle
if ((rc = PF_CreateFile(fileName)) ||
(rc = openFile((char*)fileName, &pfFileHandle)))
return rc;
if ((rc = AllocatePage(&pfFileHandle, &pfHdrPage)) ||
(rc = GetData(&pfHdrPage, &fileHdrData)) ||
(rc = AllocatePage(&pfFileHandle, &pfFirstRootPage)) ||
(rc = GetData(&pfFirstRootPage, &nodeHdrData)))
return rc;
ixFileHdr = (IX_FileHeader*)fileHdrData;
ixNodeHdr = (IX_NodePageHeader*)nodeHdrData;
ixFileHdr->attrLength = attrLength;
ixFileHdr->attrType = attrType;
ixFileHdr->bucketEntryListOffset = sizeof(IX_BucketPageHeader);
ixFileHdr->entrysPerBucket = maxBucketEntryNum;
ixFileHdr->first_leaf = 2;
ixFileHdr->nodeEntryListOffset = sizeof(IX_NodePageHeader);
ixFileHdr->nodeKeyListOffset = ixFileHdr->nodeEntryListOffset + sizeof(IX_NodeEntry) * maxKeysNum;
ixFileHdr->order = maxKeysNum;
ixFileHdr->rootPage = 2;
ixNodeHdr->firstChild = IX_NULL_CHILD;
ixNodeHdr->is_leaf = true;
ixNodeHdr->keynum = 0;
ixNodeHdr->sibling = IX_NO_MORE_NEXT_LEAF;
if ((rc = MarkDirty(&pfHdrPage)) ||
(rc = MarkDirty(&pfFirstRootPage)) ||
(rc = UnpinPage(&pfHdrPage)) ||
(rc = UnpinPage(&pfFirstRootPage)) ||
(rc = CloseFile(&pfFileHandle)))
return rc;
return SUCCESS;
}
//
// 目的: 打开已经创建的 Index File，并初始化一个 IX_IndexHandle
// 1. 检查合法性
// 2. 调用 PF_Manager::OpenFile，获得一个 PF_FileHandle
// 3. 通过 PF_FileHandle 来获取1号页面上的 RM_FileHdr 信息
//
RC OpenIndex(const char* fileName, IX_IndexHandle* indexHandle)
{
RC rc;
PF_FileHandle pfFileHandle;
PF_PageHandle pfPageHandle;
char* data;
memset(indexHandle, 0, sizeof(IX_IndexHandle));
if (indexHandle->bOpen)
return IX_IHOPENNED;
if ((rc = openFile((char*)fileName, &pfFileHandle)) ||
(rc = GetThisPage(&pfFileHandle, 1, &pfPageHandle)))
return rc;
indexHandle->bOpen = true;
if (rc = GetData(&pfPageHandle, &data))
return rc;
indexHandle->fileHeader = *(IX_FileHeader*)data;
indexHandle->fileHandle = pfFileHandle;
indexHandle->isHdrDirty = false;
if (rc = UnpinPage(&pfPageHandle))
return rc;
return SUCCESS;
}
//
// 目的: 关闭文件，将修改的数据刷写到磁盘
// 检查 indexHandle->isHdrDirty 是否为真
// 如果为真，需要GetThisPage获得文件第1页，将indexHandle中维护的IX_FileHeader
// 保存到相应的缓冲区
//
RC CloseIndex(IX_IndexHandle* indexHandle)
{
RC rc;
PF_PageHandle pfPageHandle;
char* data;
if (!(indexHandle->bOpen))
return IX_IHCLOSED;
if (indexHandle->isHdrDirty) {
if ((rc = GetThisPage(&(indexHandle->fileHandle), 1, &pfPageHandle)) ||
(rc = GetData(&pfPageHandle, &data)))
return rc;
memcpy(data, (char*) & (indexHandle->fileHeader), sizeof(IX_FileHeader));
if ((rc = MarkDirty(&pfPageHandle)) ||
(rc = UnpinPage(&pfPageHandle)))
return rc;
}
if ((rc = CloseFile(&(indexHandle->fileHandle))))
return rc;
indexHandle->bOpen = false;
indexHandle->isHdrDirty = false;
return SUCCESS;
}
//
// 目的: 初始化一个 Bucket Page，将初始化好的 Bucket Page 的 pageNum 返回
//
RC CreateBucket(IX_IndexHandle* indexHandle, PageNum* pageNum)
{
RC rc;
PF_PageHandle pfPageHandle;
char* data;
IX_BucketEntry* slotRid;
IX_BucketPageHeader* bucketPageHdr;
if ((rc = AllocatePage(&(indexHandle->fileHandle), &pfPageHandle)) ||
(rc = GetData(&pfPageHandle, &data)))
return rc;
bucketPageHdr = (IX_BucketPageHeader*)data;
slotRid = (IX_BucketEntry*)(data + indexHandle->fileHeader.bucketEntryListOffset);
for (int i = 0; i < indexHandle->fileHeader.entrysPerBucket - 1; i++)
slotRid[i].nextFreeSlot = i + 1;
slotRid[indexHandle->fileHeader.entrysPerBucket - 1].nextFreeSlot = IX_NO_MORE_BUCKET_SLOT;
bucketPageHdr->slotNum = 0;
bucketPageHdr->nextBucket = IX_NO_MORE_BUCKET_PAGE;
bucketPageHdr->firstFreeSlot = 0;
bucketPageHdr->firstValidSlot = IX_NO_MORE_BUCKET_SLOT;
*pageNum = pfPageHandle.pFrame->page.pageNum;
if ((rc = MarkDirty(&pfPageHandle)) ||
(rc = UnpinPage(&pfPageHandle)))
return rc;
return SUCCESS;
}
//
// 目的: 向给定的 bucket Page(s) 写入 RID
//
RC InsertRIDIntoBucket(IX_IndexHandle* indexHandle, PageNum bucketPageNum, RID rid)
{
RC rc;
IX_BucketPageHeader* bucketPageHdr;
PF_PageHandle bucketPage;
IX_BucketEntry* entry;
PageNum lastPageNum = bucketPageNum;
char* data;
while (bucketPageNum != IX_NO_MORE_BUCKET_PAGE)
{
lastPageNum = bucketPageNum;
if ((rc = GetThisPage(&(indexHandle->fileHandle), bucketPageNum, &bucketPage)) ||
(rc = GetData(&bucketPage, &data)))
return rc;
bucketPageHdr = (IX_BucketPageHeader*)data;
entry = (IX_BucketEntry*)(data + indexHandle->fileHeader.bucketEntryListOffset);
if (bucketPageHdr->firstFreeSlot != IX_NO_MORE_BUCKET_SLOT) {
// 存在 free slot
// 写入 RID
int free_idx = bucketPageHdr->firstFreeSlot;
int next_free_idx = entry[free_idx].nextFreeSlot;
entry[free_idx].nextFreeSlot = bucketPageHdr->firstValidSlot;
entry[free_idx].rid = rid;
bucketPageHdr->firstValidSlot = free_idx;
bucketPageHdr->firstFreeSlot = next_free_idx;
bucketPageHdr->slotNum++;
// 标记脏
if ((rc = MarkDirty(&bucketPage)) ||
(rc = UnpinPage(&bucketPage)))
return rc;
return SUCCESS;
}
bucketPageNum = bucketPageHdr->nextBucket;
}
// 遍历完了全部的 Bucket Page 都没有富裕空间了
// 创建一个新的
PageNum newPage;
PF_PageHandle newPageHandle, lastPageHandle;
char* newData, * lastData;
IX_BucketPageHeader* newHdr, * lastPageHdr;
IX_BucketEntry* newEntry;
if ((rc = CreateBucket(indexHandle, &newPage)) ||
(rc = GetThisPage(&(indexHandle->fileHandle), newPage, &newPageHandle)) ||
(rc = GetData(&newPageHandle, &newData)))
return rc;
newHdr = (IX_BucketPageHeader*)newData;
newEntry = (IX_BucketEntry*)(newData + indexHandle->fileHeader.bucketEntryListOffset);
int free_idx = newHdr->firstFreeSlot;
int next_free_idx = newEntry[free_idx].nextFreeSlot;
newEntry[free_idx].nextFreeSlot = newHdr->firstValidSlot;
newEntry[free_idx].rid = rid;
newHdr->firstValidSlot = free_idx;
newHdr->firstFreeSlot = next_free_idx;
newHdr->slotNum++;
if ((rc = GetThisPage(&(indexHandle->fileHandle), lastPageNum, &lastPageHandle)) ||
(rc = GetData(&lastPageHandle, &lastData)))
return rc;
lastPageHdr = (IX_BucketPageHeader*)lastData;
lastPageHdr->nextBucket = newPage;
if ((rc = MarkDirty(&newPageHandle)) ||
(rc = MarkDirty(&lastPageHandle)) ||
(rc = UnpinPage(&newPageHandle)) ||
(rc = UnpinPage(&lastPageHandle)))
return rc;
return SUCCESS;
}
//
// 目的: 在 Bucket Page(s) 中查找匹配的 rid，并删除相应的 rid
//
RC DeleteRIDFromBucket(IX_IndexHandle* indexHandle, PageNum bucketPageNum, const RID* rid, PageNum nodePage, RID* nodeRid)
{
RC rc;
PF_PageHandle bucketPageHandle, prePageHandle;
char* data, * preData;
IX_BucketPageHeader* bucketPageHdr, * preBucketHdr;
IX_BucketEntry* entry;
PageNum prePageNum = nodePage;
while (bucketPageNum != IX_NO_MORE_BUCKET_PAGE)
{
if ((rc = GetThisPage(&(indexHandle->fileHandle), bucketPageNum, &bucketPageHandle)) ||
(rc = GetData(&bucketPageHandle, &data)))
return rc;
bucketPageHdr = (IX_BucketPageHeader*)data;
entry = (IX_BucketEntry*)(data + indexHandle->fileHeader.bucketEntryListOffset);
SlotNum validSlot = bucketPageHdr->firstValidSlot;
SlotNum preValidSlot = IX_NO_MORE_BUCKET_SLOT;
while (validSlot != IX_NO_MORE_BUCKET_SLOT)
{
SlotNum next_valid = entry[validSlot].nextFreeSlot;
if (ridEqual(&(entry[validSlot].rid), rid)) {
if (preValidSlot == IX_NO_MORE_BUCKET_SLOT) {
bucketPageHdr->firstValidSlot = next_valid;
}
else {
entry[preValidSlot].nextFreeSlot = next_valid;
}
entry[validSlot].nextFreeSlot = bucketPageHdr->firstFreeSlot;
bucketPageHdr->firstFreeSlot = validSlot;
bucketPageHdr->slotNum--;
if (!(bucketPageHdr->slotNum)) {
// 当前 bucket 删空了
if (prePageNum == nodePage) {
// 前一个 Page 是 Node Page
nodeRid->pageNum = bucketPageHdr->nextBucket;
}
else {
// 前一个 Page 是 Bucket Page
if ((rc = GetThisPage(&(indexHandle->fileHandle), prePageNum, &prePageHandle)) ||
(rc = GetData(&prePageHandle, &preData)))
return rc;
IX_BucketPageHeader* preBucketPageHdr = (IX_BucketPageHeader*)preData;
preBucketPageHdr->nextBucket = bucketPageHdr->nextBucket;
if ((rc = MarkDirty(&prePageHandle)) ||
(rc = UnpinPage(&prePageHandle)))
return rc;
}
if ((rc = MarkDirty(&bucketPageHandle)) ||
(rc = UnpinPage(&bucketPageHandle)))
return rc;
// dispose 掉这一页空记录的 bucket page
if (rc = DisposePage(&(indexHandle->fileHandle), bucketPageNum))
return rc;
return SUCCESS;
}
if ((rc = MarkDirty(&bucketPageHandle)) ||
(rc = UnpinPage(&bucketPageHandle)))
return rc;
return SUCCESS;
}
preValidSlot = validSlot;
validSlot = entry[validSlot].nextFreeSlot;
}
if (rc = UnpinPage(&bucketPageHandle))
return rc;
prePageNum = bucketPageNum;
bucketPageNum = bucketPageHdr->nextBucket;
}
// 遍历完了也没有找到
return IX_DELETE_NO_RID;
}
//
// 目的: dispose 掉 全部的 BucketPage
//
RC DisposeAllBucket(IX_IndexHandle* indexHandle, PageNum bucketPageNum)
{
RC rc;
PF_PageHandle bucketPageHandle;
char* data;
IX_BucketPageHeader* bucketPageHdr;
PageNum nextPage;
while (bucketPageNum != IX_NO_MORE_BUCKET_PAGE) {
if ((rc = GetThisPage(&(indexHandle->fileHandle), bucketPageNum, &bucketPageHandle)) ||
(rc = GetData(&bucketPageHandle, &data)))
return rc;
bucketPageHdr = (IX_BucketPageHeader*)data;
nextPage = bucketPageHdr->nextBucket;
if ((rc = UnpinPage(&bucketPageHandle)) ||
(rc = DisposePage(&(indexHandle->fileHandle), bucketPageNum)))
return rc;
bucketPageNum = nextPage;
}
return SUCCESS;
}
//
// 目的: 在 Node 文件页中 查找指定 pData
// 找到最大的小于等于 pData 的索引位置保存在 idx 中
// 如果存在等于 返回 true 否则返回 false
// pData: 用户指定的数据指针
// key: Node 文件的关键字区首地址指针
// s: 搜索范围起始索引
// e: 搜索范围终止索引
// 上述范围为包含
//
bool findKeyInNode(IX_IndexHandle* indexHandle, void* pData, void* key, int s, int e, int* idx)
{
int mid, cmpres;
int attrLen = indexHandle->fileHeader.attrLength;
while (s < e) {
mid = ((s + e) >> 1) + 1;
cmpres = IXComp(indexHandle, (char*)key + attrLen * mid, pData, attrLen, attrLen);
if (cmpres < 0) {
s = mid;
}
else if (cmpres > 0) {
e = mid - 1;
}
else {
*idx = mid;
return true;
}
}
if (s > e ||
(cmpres = IXComp(indexHandle, (char*)key + attrLen * s, pData, attrLen, attrLen)) > 0) {
*idx = s - 1;
return false;
}
else {
*idx = s;
return cmpres == 0;
}
}
//
// shift 不负责获得页面，并设置页面脏
// entry: 页面指针区首地址
// key: 页面关键字区首地址
// idx: 从idx开始到结束位置 len - 1 进行移动
// dir: true 表示 向后移动; false 反之
//
void shift(IX_IndexHandle* indexHandle, char* entry, char* key, int idx, int len, bool dir)
{
int attrLen = indexHandle->fileHeader.attrLength;
if (dir) {
for (int i = len - 1; i >= idx; i--) {
memcpy(key + attrLen * (i + 1), key + attrLen * i, attrLen);
memcpy(entry + sizeof(IX_NodeEntry) * (i + 1),
entry + sizeof(IX_NodeEntry) * i, sizeof(IX_NodeEntry));
}
}
else {
for (int i = idx; i < len; i++) {
memcpy(key + attrLen * (i - 1), key + attrLen * i, attrLen);
memcpy(entry + sizeof(IX_NodeEntry) * (i - 1),
entry + sizeof(IX_NodeEntry) * i, sizeof(IX_NodeEntry));
}
}
}
//
// splitChild 不负责 parent 页面的释放，但是负责子节点页面和新页面的释放
//
RC splitChild(IX_IndexHandle* indexHandle, PF_PageHandle* parent, int idx, PageNum child)
{
RC rc;
char* data, * par_entry, * par_key;
char* child_entry, * child_key;
char* new_entry, * new_key;
PF_PageHandle childPageHandle, newPageHandle;
PageNum newPageNum;
IX_NodePageHeader* parentHdr, * childHdr, * newPageHdr;
int childKeyNum;
int attrLen = indexHandle->fileHeader.attrLength;
if (rc = GetData(parent, &data))
return rc;
parentHdr = (IX_NodePageHeader*)data;
par_entry = data + indexHandle->fileHeader.nodeEntryListOffset;
par_key = data + indexHandle->fileHeader.nodeKeyListOffset;
if ((rc = GetThisPage(&(indexHandle->fileHandle), child, &childPageHandle)) ||
(rc = GetData(&childPageHandle, &data)))
return rc;
childHdr = (IX_NodePageHeader*)data;
childKeyNum = childHdr->keynum;
child_entry = data + indexHandle->fileHeader.nodeEntryListOffset;
child_key = data + indexHandle->fileHeader.nodeKeyListOffset;
if ((rc = AllocatePage(&(indexHandle->fileHandle), &newPageHandle)) ||
(rc = GetData(&newPageHandle, &data)))
return rc;
newPageHdr = (IX_NodePageHeader*)data;
newPageNum = newPageHandle.pFrame->page.pageNum;
new_entry = data + indexHandle->fileHeader.nodeEntryListOffset;
new_key = data + indexHandle->fileHeader.nodeKeyListOffset;
IX_NodeEntry* midChildEntry = (IX_NodeEntry*)(child_entry + sizeof(IX_NodeEntry) * (childKeyNum / 2));
if (childHdr->is_leaf) {
// 子节点是一个叶子节点
// 将叶子节点从 childKeyNum / 2 开始的所有信息拷贝到新节点位置
memcpy(new_entry, child_entry + sizeof(IX_NodeEntry) * (childKeyNum / 2),
sizeof(IX_NodeEntry) * (childKeyNum - (childKeyNum / 2)));
memcpy(new_key, child_key + attrLen * (childKeyNum / 2),
attrLen * (childKeyNum - (childKeyNum / 2)));
newPageHdr->firstChild = IX_NULL_CHILD;
newPageHdr->is_leaf = true;
newPageHdr->keynum = childKeyNum - (childKeyNum / 2);
newPageHdr->sibling = childHdr->sibling;
}
else {
// 子节点是内部节点
// 将叶子节点从 childKeyNum / 2 + 1 开始的所有信息拷贝到新节点位置
memcpy(new_entry, child_entry + sizeof(IX_NodeEntry) * (childKeyNum / 2 + 1),
sizeof(IX_NodeEntry) * (childKeyNum - (childKeyNum / 2) - 1));
memcpy(new_key, child_key + attrLen * (childKeyNum / 2 + 1),
attrLen * (childKeyNum - (childKeyNum / 2) - 1));
newPageHdr->firstChild = midChildEntry->rid.pageNum;
newPageHdr->is_leaf = false;
newPageHdr->keynum = childKeyNum - (childKeyNum / 2) - 1;
newPageHdr->sibling = childHdr->sibling;
}
childHdr->keynum = childKeyNum / 2;
childHdr->sibling = newPageNum;
// 移动父节点数据
shift(indexHandle, par_entry, par_key, idx + 1, parentHdr->keynum, true);
// 把孩子节点的中间数据写入到父节点
IX_NodeEntry* parEntry = (IX_NodeEntry*)(par_entry + sizeof(IX_NodeEntry) * (idx + 1));
parEntry->tag = OCCUPIED;
parEntry->rid.pageNum = newPageNum;
parEntry->rid.slotNum = IX_USELESS_SLOTNUM;
memcpy(par_key + attrLen * (idx + 1), child_key + attrLen * (childKeyNum / 2), attrLen);
parentHdr->keynum++;
if ((rc = MarkDirty(&childPageHandle)) ||
(rc = MarkDirty(&newPageHandle)) ||
(rc = MarkDirty(parent)) ||
(rc = UnpinPage(&childPageHandle)) ||
(rc = UnpinPage(&newPageHandle)))
return rc;
return SUCCESS;
}
//
// InsertEntry 的帮助函数
//
RC InsertEntryIntoTree(IX_IndexHandle* indexHandle, PageNum node, void* pData, const RID* rid)
{
RC rc;
PF_PageHandle nodePage;
char* data, * entry, * key;
IX_NodePageHeader* nodePageHdr;
int keyNum;
int attrLen = indexHandle->fileHeader.attrLength;
if ((rc = GetThisPage(&(indexHandle->fileHandle), node, &nodePage)) ||
(rc = GetData(&nodePage, &data)))
return rc;
nodePageHdr = (IX_NodePageHeader*)data;
keyNum = nodePageHdr->keynum;
entry = data + indexHandle->fileHeader.nodeEntryListOffset;
key = data + indexHandle->fileHeader.nodeKeyListOffset;
if (nodePageHdr->is_leaf) {
// 当前节点是叶子节点
// 1. 查找叶子节点中是否存在相同key的slot
int idx;
bool findRes = findKeyInNode(indexHandle, pData, key, 0, keyNum - 1, &idx);
if (findRes) {
std::cout << "相同 key 插入" << std::endl;
// 存在该key
// 获取对应索引位置 entry 区的信息
IX_NodeEntry* pIdxEntry = (IX_NodeEntry*)(entry + sizeof(IX_NodeEntry) * idx);
// 读取该项的标志位 char tag
char tag = pIdxEntry->tag;
RID* thisRid = &(pIdxEntry->rid);
PageNum bucketPageNum;
PF_PageHandle bucketPageHandle;
assert(tag != 0);
if (tag == OCCUPIED) {
// 尚未标记为重复键值, 需要创建一个 Bucket File
// 获取新分配的 Bucket Page 的 pageHandle,并插入记录
if ((rc = CreateBucket(indexHandle, &bucketPageNum)) ||
(rc = InsertRIDIntoBucket(indexHandle, bucketPageNum, *thisRid)) ||
(rc = InsertRIDIntoBucket(indexHandle, bucketPageNum, *rid)))
return rc;
pIdxEntry->tag = DUP;
thisRid->pageNum = bucketPageNum;
thisRid->slotNum = IX_USELESS_SLOTNUM;
if ((rc = MarkDirty(&nodePage)) ||
(rc = UnpinPage(&nodePage)))
return rc;
return SUCCESS;
}
else if (tag == DUP) {
// 已经标记为重复键值，获取对应的 Bucket File，插入记录
bucketPageNum = thisRid->pageNum;
if (rc = InsertRIDIntoBucket(indexHandle, bucketPageNum, *rid))
return rc;
if ((rc = MarkDirty(&nodePage)) ||
(rc = UnpinPage(&nodePage)))
return rc;
return SUCCESS;
}
}
else {
// 不存在
// idx 中保存了 <= pData 的索引位置
// 需要把 idx + 1 之后的 指针区 和 关键字区 的内容向后移动
// 再把数据 RID 和 关键字 写到 idx + 1 位置
shift(indexHandle, entry, key, idx + 1, keyNum, true);
IX_NodeEntry* pIdxEntry = (IX_NodeEntry*)(entry + sizeof(IX_NodeEntry) * (idx + 1));
pIdxEntry->tag = OCCUPIED;
pIdxEntry->rid = *rid;
memcpy(key + attrLen * (idx + 1), pData, attrLen);
int parentKeyNum = ++(nodePageHdr->keynum);
if ((rc = MarkDirty(&nodePage)) ||
(rc = UnpinPage(&nodePage)))
return rc;
return (parentKeyNum >= indexHandle->fileHeader.order) ? IX_CHILD_NODE_OVERFLOW : SUCCESS;
}
}
else {
// 当前节点是内部节点
// 找到 小于等于 输入关键字的最大索引位置，递归执行 InsertEntryIntoTree
int idx;
bool findRes = findKeyInNode(indexHandle, pData, key, 0, keyNum - 1, &idx);
IX_NodeEntry* nodeEntry = (IX_NodeEntry*)entry;
PageNum child;
if (idx == -1)
child = nodePageHdr->firstChild;
else
child = nodeEntry[idx].rid.pageNum;
// 在深入 B+树 进行递归之前，释放掉当前 page
if (rc = UnpinPage(&nodePage))
return rc;
rc = InsertEntryIntoTree(indexHandle, child, pData, rid);
if (rc == IX_CHILD_NODE_OVERFLOW) {
// 子节点发生了 overflow
// Get 当前节点的 Page
if (rc = GetThisPage(&(indexHandle->fileHandle), node, &nodePage))
return rc;
// split 子节点
if (rc = splitChild(indexHandle, &nodePage, idx, child))
return rc;
if (rc = GetData(&nodePage, &data))
return rc;
int parentKeyNum = ((IX_NodePageHeader*)data)->keynum;
if (rc = UnpinPage(&nodePage))
return rc;
return (parentKeyNum >= indexHandle->fileHeader.order) ? IX_CHILD_NODE_OVERFLOW : SUCCESS;
}
return rc;
}
return SUCCESS;
}