RC IX_IndexHandle::DeleteEntry(void *attr,
const RID &rid)
{
RC rc;
if (!_opened)
return IX_INVALIDINDEXHANDLE;
PF_PageHandle thisPage;
if ((rc = IX_LocateAttr(*this, (char *) attr, thisPage)))
return rc;
char *thisData;
if ((rc = thisPage.GetData(thisData)))
return rc;
IX_PageHeader *thisHeader = reinterpret_cast<IX_PageHeader *>(thisData);
if (thisHeader->numKeys == 0)
return IX_EMPTYNODE;
char *thisKey = NULL;
for (unsigned i = 0; i < thisHeader->numKeys; i++) {
thisKey = IX_GetLeafKey(thisData, _attrLength, i);
RID thisRid = IX_GetLeafRID(thisKey);
if (thisRid == rid) {
IX_SetLeafDeleted(thisKey, true);
PageNum thisPageNum;
if ((rc = thisPage.GetPageNum(thisPageNum)))
return rc;
if ((rc = _fileHandle.MarkDirty(thisPageNum)))
return rc;
break;
}
}
PageNum thisPageNum;
if ((rc = thisPage.GetPageNum(thisPageNum)))
return rc;
if ((rc = _fileHandle.UnpinPage(thisPageNum)))
return rc;
return 0;
}
RC IX_IndexHandle::SolveUpperOverflow(PageNum thisPageNum)
{
RC rc;
PF_PageHandle thisPage;
if ((rc = _fileHandle.GetThisPage(thisPageNum, thisPage)))
return rc;
char *thisData;
if ((rc = thisPage.GetData(thisData)))
return rc;
IX_PageHeader *thisHeader = reinterpret_cast<IX_PageHeader *>(thisData);
// 递归终止条件:不满足分裂条件。
if (thisHeader->flag & IXF_LEAF) {
if (thisHeader->numKeys < IX_MaxLeafKeys(_attrLength))
return 0;
} else {
if (thisHeader->numKeys < IX_MaxInternalKeys(_attrLength))
return 0;
}
// 分配新页
PF_PageHandle anotherPage;
if ((rc = _fileHandle.AllocatePage(anotherPage)))
return rc;
char *anotherData;
if ((rc = anotherPage.GetData(anotherData)))
return rc;
IX_PageHeader *anotherHeader = reinterpret_cast<IX_PageHeader *>(anotherData);
PageNum anotherPageNum;
if ((rc = anotherPage.GetPageNum(anotherPageNum)))
return rc;
if (thisHeader->flag & IXF_LEAF) {
// Leaf page.
unsigned anotherStart = thisHeader->numKeys / 2;
anotherHeader->numKeys = thisHeader->numKeys - anotherStart;
anotherHeader->flag = IXF_LEAF;
anotherHeader->parent = thisHeader->parent;
// Move half of the keys to another page.
for (unsigned i = anotherStart; i < thisHeader->numKeys; i++) {
char *thisKey = IX_GetLeafKey(thisData, _attrLength, i);
char *anotherKey = IX_GetLeafKey(anotherData, _attrLength, i - anotherStart);
memcpy(anotherKey, thisKey, sizeof(RID) + sizeof(int) + _attrLength);
}
thisHeader->numKeys = anotherStart;
PageNum nextPageNum = thisHeader->next;
if (nextPageNum != 0) {
PF_PageHandle nextPage;
if ((rc = _fileHandle.GetThisPage(nextPageNum, nextPage)))
return rc;
char *nextData;
if ((rc = nextPage.GetData(nextData)))
return rc;
IX_PageHeader *nextHeader = reinterpret_cast<IX_PageHeader *>(nextData);
nextHeader->prev = anotherPageNum;
if ((rc = _fileHandle.MarkDirty(nextPageNum)))
return rc;
if ((rc = _fileHandle.UnpinPage(nextPageNum)))
return rc;
}
anotherHeader->next = nextPageNum;
anotherHeader->prev = thisPageNum;
thisHeader->next = anotherPageNum;
} else {
// Internal page.
unsigned anotherStart = thisHeader->numKeys / 2;
anotherHeader->numKeys = thisHeader->numKeys - anotherStart;
anotherHeader->flag = 0;
anotherHeader->parent = thisHeader->parent;
anotherHeader->next = anotherHeader->prev = 0;
for (unsigned i = anotherStart; i < thisHeader->numKeys; i++) {
char *thisKey = IX_GetInternalKey(thisData, _attrLength, i);
char *anotherKey = IX_GetInternalKey(anotherData, _attrLength, i - anotherStart);
memcpy(anotherKey, thisKey, sizeof(PageNum) + _attrLength);
// 修改该Child的父亲指针
PageNum childPageNum = IX_GetInternalChild(anotherKey);
PF_PageHandle childPage;
if ((rc = _fileHandle.GetThisPage(childPageNum, childPage)))
return rc;
char *childData;
if ((rc = childPage.GetData(childData)))
return rc;
IX_PageHeader *childHeader = (IX_PageHeader *)childData;
childHeader->parent = anotherPageNum;
if ((rc = _fileHandle.MarkDirty(childPageNum)))
return rc;
if ((rc = _fileHandle.UnpinPage(childPageNum)))
return rc;
}
thisHeader->numKeys = anotherStart;
}
// 如果thisPage是根节点，就要首先创建一个新的空的根节点，并将指向thisPage的指针放进去
if (thisHeader->flag & IXF_ROOT) {
PF_PageHandle rootPage;
if ((rc = _fileHandle.AllocatePage(rootPage)))
return rc;
char *rootData;
if ((rc = rootPage.GetData(rootData)))
return rc;
IX_PageHeader *rootHeader = reinterpret_cast<IX_PageHeader *>(rootData);
rootHeader->flag = IXF_ROOT;
rootHeader->numKeys = 1;
rootHeader->parent = rootHeader->next = rootHeader->prev = 0;
char *thisFirstAttr;
if (thisHeader->flag & IXF_LEAF)
thisFirstAttr = IX_GetLeafAttr(IX_GetLeafKey(thisData, _attrLength, 0));
else
thisFirstAttr = IX_GetInternalAttr(IX_GetInternalKey(thisData, _attrLength, 0));
char *rootFirstKey = IX_GetInternalKey(rootData, _attrLength, 0);
IX_SetInternalChild(rootFirstKey, thisPageNum);
memcpy(IX_GetInternalAttr(rootFirstKey), thisFirstAttr, _attrLength);
if ((rc = rootPage.GetPageNum(_rootNum)))
return rc;
if ((rc = _fileHandle.MarkDirty(_rootNum)))
return rc;
if ((rc = _fileHandle.UnpinPage(_rootNum)))
return rc;
thisHeader->parent = _rootNum;
thisHeader->flag &= ~IXF_ROOT;
anotherHeader->parent = _rootNum;
// 记得要修改INDEX的头部信息块
PF_PageHandle fileHeaderPage;
if ((rc = _fileHandle.GetFirstPage(fileHeaderPage)))
return rc;
char *fileHeaderData;
if ((rc = fileHeaderPage.GetData(fileHeaderData)))
return rc;
IX_FileHeader *fileHeader = reinterpret_cast<IX_FileHeader *>(fileHeaderData);
fileHeader->rootNum = _rootNum;
PageNum fileHeaderNum;
if ((rc = fileHeaderPage.GetPageNum(fileHeaderNum)))
return rc;
if ((rc = _fileHandle.MarkDirty(fileHeaderNum)))
return rc;
if ((rc = _fileHandle.UnpinPage(fileHeaderNum)))
return rc;
}
// 在父节点中插入一个新的key，key值为anotherPage的最小值。
static int magicint = 0;
PF_PageHandle parentPage;
if ((rc = _fileHandle.GetThisPage(thisHeader->parent, parentPage)))
return rc;
char *parentData;
if ((rc = parentPage.GetData(parentData)))
return rc;
IX_PageHeader *parentHeader = reinterpret_cast<IX_PageHeader *>(parentData);
char *anotherFirstAttr = IX_GetInternalAttr(IX_GetInternalKey(anotherData, _attrLength, 0));
unsigned iKey;
for (iKey = 0; iKey < parentHeader->numKeys; iKey++) {
char *pKey = IX_GetInternalKey(parentData, _attrLength, iKey);
if (IX_GetInternalChild(pKey) == thisPageNum)
break;
}
// 将iKey+1与其之后的key都向后移动一位，在空出的位置iKey+1上填入新的key
for (unsigned temp = parentHeader->numKeys; temp > iKey+1; temp--) {
char *keyNext = IX_GetInternalKey(parentData, _attrLength, temp);
char *keyPrev = IX_GetInternalKey(parentData, _attrLength, temp-1);
memcpy(IX_GetInternalAttr(keyNext), IX_GetInternalAttr(keyPrev), _attrLength);
IX_SetInternalChild(keyNext, IX_GetInternalChild(keyPrev));
}
parentHeader->numKeys++;
char *pKey = IX_GetInternalKey(parentData, _attrLength, iKey+1);
memcpy(IX_GetInternalAttr(pKey), anotherFirstAttr, _attrLength);
IX_SetInternalChild(pKey, anotherPageNum);
PageNum parentPageNum;
if ((rc = parentPage.GetPageNum(parentPageNum)))
return rc;
if ((rc = _fileHandle.MarkDirty(parentPageNum)))
return rc;
if ((rc = _fileHandle.UnpinPage(parentPageNum)))
return rc;
if ((rc = _fileHandle.MarkDirty(thisPageNum)))
return rc;
if ((rc = _fileHandle.UnpinPage(thisPageNum)))
return rc;
if ((rc = _fileHandle.MarkDirty(anotherPageNum)))
return rc;
if ((rc = _fileHandle.UnpinPage(anotherPageNum)))
return rc;
return SolveUpperOverflow(parentPageNum);
}
RC IX_IndexHandle::InsertEntry(void *attr,
const RID &rid)
{
RC rc;
if (!_opened)
return IX_INVALIDINDEXHANDLE;
PF_PageHandle thisPage;
if ((rc =_fileHandle.GetThisPage(_rootNum, thisPage)))
return rc;
char *pData;
if ((rc = thisPage.GetData(pData)))
return rc;
IX_PageHeader *thisHeader = reinterpret_cast<IX_PageHeader *>(pData);
if (thisHeader->numKeys == 0) {
// 插入第一个元素的特殊情况
thisHeader->numKeys = 1;
char *pKey = IX_GetLeafKey(pData, _attrLength, 0);
IX_SetLeafRID(pKey, rid);
char *thisAttr = IX_GetLeafAttr(pKey);
memcpy(thisAttr, attr, _attrLength);
if ((rc = _fileHandle.MarkDirty(_rootNum)))
return rc;
if ((rc = _fileHandle.UnpinPage(_rootNum)))
return rc;
return 0;
}
if ((rc = _fileHandle.UnpinPage(_rootNum)))
return rc;
if ((rc = IX_LocateAttr(*this, (char *)attr, thisPage)))
return rc;
if ((rc = thisPage.GetData(pData)))
return rc;
thisHeader = reinterpret_cast<IX_PageHeader *>(pData);
unsigned iKey;
for (iKey = 0; iKey < thisHeader->numKeys; iKey++) {
char *pThisKey = IX_GetLeafKey(pData, _attrLength, iKey);
if (IX_AttrEQ(IX_GetLeafAttr(pThisKey), (char *)attr, _attrType, _attrLength)) {
if (IX_IsLeafDeleted(pThisKey))
break;
else
return IX_DUPLICATEENTRY;
}
if (IX_AttrGT(IX_GetLeafAttr(pThisKey), (char *)attr, _attrType, _attrLength))
break;
}
bool isDeleted = false;
char *pThisKey = IX_GetLeafKey(pData, _attrLength, iKey);
if (IX_IsLeafDeleted(pThisKey)) {
// 不需要移动位置，直接替换前已经被标记为删除的。
isDeleted = true;
} else {
// 现在iKey指向应该插入新索引的位置，要首先将后面的索引向后移动一个位置，
// 空出当前位置，将新索引放在这里。
for (unsigned temp = thisHeader->numKeys; temp > iKey; temp--) {
char *pThisKey = IX_GetLeafKey(pData, _attrLength, temp);
char *pPrevKey = IX_GetLeafKey(pData, _attrLength, temp-1);
RID tempRid = IX_GetLeafRID(pPrevKey);
IX_SetLeafRID(pThisKey, tempRid);
memcpy(IX_GetLeafAttr(pThisKey), IX_GetLeafAttr(pPrevKey), _attrLength);
}
thisHeader->numKeys++;
}
pThisKey = IX_GetLeafKey(pData, _attrLength, iKey);
IX_SetLeafRID(pThisKey, rid);
IX_SetLeafDeleted(pThisKey, false);
memcpy(IX_GetLeafAttr(pThisKey), attr, _attrLength);
PageNum thisParentPageNum = thisHeader->parent;
PageNum thisPageNum;
if ((rc = thisPage.GetPageNum(thisPageNum)))
return rc;
if ((rc = _fileHandle.MarkDirty(thisPageNum)))
return rc;
if ((rc = _fileHandle.UnpinPage(thisPageNum)))
return rc;
// 如果更新的为最左键，则需要向上更新键值
if (iKey == 0 && thisParentPageNum != 0)
UpdateKey(thisParentPageNum, (char *)attr);
// 开始从该节点逐层向上检查是否溢出
rc = SolveUpperOverflow(thisPageNum);
// PrintTree(_rootNum);
return rc;
}
RC RM_Manager::CreateFile (const char *fileName, int recordSize) {
/* Determine the number of records that can be stored in a single
* page. If this number is less than 1, return an error. */
int recordsPerPage;
double x = (double)(PF_PAGE_SIZE - RM_PAGESUBHDR_SIZE) - 1.0;
double y = (double)recordSize + 0.125;
recordsPerPage = (int)(x/y);
if (recordsPerPage < 1) {
return RM_INVALIDRECSIZE;
}
if (DEBUG) {
printf ("recordsPerPage = %d\n", recordsPerPage);
}
RC rc;
/* Create file by using the paged file manager */
rc = pfm.CreateFile (fileName);
if (rc != SUCCESS) { return rc; }
PF_FileHandle pfFileHandle;
/* Open the created file */
rc = pfm.OpenFile (fileName, pfFileHandle);
if (rc != SUCCESS) { return rc; }
PF_PageHandle pfPageHandle;
/* Allocate a new page for the RM header page */
rc = pfFileHandle.AllocatePage (pfPageHandle);
if (rc != SUCCESS) { return rc; }
char *pData;
PageNum pageNum;
/* Get ptr to the contents (data) of the RM header page */
rc = pfPageHandle.GetData (pData);
if (rc != SUCCESS) { return rc; }
/* Get the page number of the RM header page */
rc = pfPageHandle.GetPageNum (pageNum);
if (rc != SUCCESS) { return rc; }
/* Construct the sub-header */
RM_FileSubHeader
fileSubHeader = { 0,/* # of records currently stored in file */
recordSize,
recordsPerPage,
/* offset in bytes of the first record */
RM_PAGESUBHDR_SIZE+(recordsPerPage+8)/8
};
/* Copy the sub-header to the page */
memcpy (&pData[0], &fileSubHeader, RM_FILESUBHDR_SIZE);
/* Initialise the rest of the page. The rest of the page is
* reserved for a bitmap for NON_FULL, FULL data pages. NON_FULL
* data pages are those pages that have some empty slots in them.
* FULL data pages do not have empty slots and therefore cannot
* store additional records. */
memset (&pData[RM_FILESUBHDR_SIZE], 0, PF_PAGE_SIZE-RM_FILESUBHDR_SIZE);
/* Because we modified the RM header page, we write it to disk */
rc = pfFileHandle.ForcePage (pageNum);
if (rc != SUCCESS) { return rc; }
/* We now unpin the header page because we are done modifying it */
rc = pfFileHandle.UnpinPage (pageNum);
if (rc != SUCCESS) { return rc; }
return SUCCESS;
}