HeapFile* IndexNestedLoopJoin(JoinSpec specOfR, JoinSpec specOfS)
{
Status status = OK;
// Create a HeapFile for join results
HeapFile* joinedFile = new HeapFile(NULL, status);
if (OK != status)
{
cerr << "ERROR: cannot create a file for the joined relation.\n";
return NULL;
}
int recLenR = specOfR.recLen;
int recLenS = specOfS.recLen;
int recLenJoined = recLenR + recLenS;
char* recR = new char[recLenR];
char* recS = new char[recLenS];
char* recJoined = new char[recLenJoined];
RecordID ridR, ridS, ridJoined;
// Build the B+-tree index on the inner relation (S)
Scan* scanS = specOfS.file->OpenScan(status);
if (OK != status)
{
cerr << "ERROR: cannot open scan on the relation S heap file.\n";
return NULL;
}
BTreeFile* bTree = new BTreeFile(status, "IJBT", ATTR_INT, sizeof(int));
while (OK == scanS->GetNext(ridS, recS, recLenS))
{
bTree->Insert(recS + specOfS.offset, ridS);
}
delete scanS;
// Iterate through the outer relation (R) and join
Scan* scanR = specOfR.file->OpenScan(status);
if (OK != status)
{
cerr << "ERROR: cannot open scan on the relation R heap file.\n";
return NULL;
}
while (OK == scanR->GetNext(ridR, recR, recLenR))
{
int* joinArgR = (int*)&recR[specOfR.offset];
BTreeFileScan* bTreeScan = (BTreeFileScan*)bTree->OpenSearchScan(joinArgR, joinArgR);
int key;
while (OK == bTreeScan->GetNext(ridS, &key))
{
specOfS.file->GetRecord(ridS, recS, recLenS);
MakeNewRecord(recJoined, recR, recS, recLenR, recLenS);
joinedFile->InsertRecord(recJoined, recLenJoined, ridJoined);
}
delete bTreeScan;
}
// Release the allocated resources
delete scanR;
delete[] recR;
delete[] recS;
delete[] recJoined;
delete bTree;
return joinedFile;
}
HeapFile* BlockNestedLoopJoin(JoinSpec specOfR, JoinSpec specOfS, int B)
{
Status status = OK;
// Create a HeapFile for join results
HeapFile* joinedFile = new HeapFile(NULL, status);
if (OK != status)
{
cerr << "ERROR: cannot create a file for the joined relation.\n";
return NULL;
}
int recLenR = specOfR.recLen;
int recLenS = specOfS.recLen;
int recLenJoined = recLenR + recLenS;
char* recBlockR = new char[B]; // Allocate memory for the block
char* recS = new char[recLenS];
char* recJoined = new char[recLenJoined];
RecordID ridR, ridS, ridJoined;
Scan* scanR = specOfR.file->OpenScan(status);
if (OK != status)
{
cerr << "ERROR: cannot open scan on the relation R heap file.\n";
return NULL;
}
const int recordsPerBlock = B / recLenR;
bool lastBlock = false;
while (!lastBlock)
{
// Fill the block
int i;
for (i = 0; i < recordsPerBlock; i++)
{
if (OK != scanR->GetNext(ridR, recBlockR + i*recLenR, recLenR))
{
lastBlock = true;
break;
}
}
int lastRecordIndex = i;
Scan* scanS = specOfS.file->OpenScan(status);
if (OK != status)
{
cerr << "ERROR: cannot open scan on the relation S heap file.\n";
return NULL;
}
while (OK == scanS->GetNext(ridS, recS, recLenS))
{
int* joinArgS = (int*)&recS[specOfS.offset];
for (int currentRecordIndex = 0; currentRecordIndex < lastRecordIndex; currentRecordIndex++)
{
char* currentRecordPtr = recBlockR + (currentRecordIndex * recLenR);
int* joinArgR = (int*)(currentRecordPtr + specOfR.offset);
if (*joinArgR == *joinArgS)
{
MakeNewRecord(recJoined, currentRecordPtr, recS, recLenR, recLenS);
joinedFile->InsertRecord(recJoined, recLenJoined, ridJoined);
}
}
}
delete scanS;
}
// Release the allocated resources
delete scanR;
delete[] recBlockR;
delete[] recS;
delete[] recJoined;
return joinedFile;
}
//---------------------------------------------------------------
// TupleNestedLoop::Execute
//
// Input: left - The left relation to join.
// right - The right relation to join.
// Output: out - The relation to hold the ouptut.
// Return: OK if join completed succesfully. FAIL otherwise.
//
// Purpose: Performs a nested loop join on relations left and right
// a tuple a time. You can assume that left is the outer
// relation and right is the inner relation.
//---------------------------------------------------------------
Status TupleNestedLoops::Execute(JoinSpec& left, JoinSpec& right, JoinSpec& out) {
JoinMethod::Execute(left, right, out);
// Create the temporary heapfile
Status st;
HeapFile *tmpHeap = new HeapFile(NULL, st);
if (st != OK) {
std::cerr << "Failed to create output heapfile." << std::endl;
return FAIL;
}
// Open scan on left relation
Status leftStatus;
Scan *leftScan = left.file->OpenScan(leftStatus);
if (leftStatus != OK) {
std::cerr << "Failed to open scan on left relation." << std::endl;
return FAIL;
}
// Loop over the left relation
char *leftRec = new char[left.recLen];
while (true) {
RecordID leftRid;
leftStatus = leftScan->GetNext(leftRid, leftRec, left.recLen);
if (leftStatus == DONE) break;
if (leftStatus != OK) return FAIL;
// The join attribute on left relation
int *leftJoinValPtr = (int*)(leftRec + left.offset);
// Open scan on right relation
Status rightStatus;
Scan *rightScan = right.file->OpenScan(rightStatus);
if (rightStatus != OK) {
std::cerr << "Failed to open scan on right relation." << std::endl;
return FAIL;
}
// Loop over right relation
char *rightRec = new char[right.recLen];
while (true) {
RecordID rightRid;
rightStatus = rightScan->GetNext(rightRid, rightRec, right.recLen);
if (rightStatus == DONE) break;
if (rightStatus != OK) return FAIL;
// Compare join attribute
int *rightJoinValPtr = (int*)(rightRec + right.offset);
if (*leftJoinValPtr == *rightJoinValPtr) {
// Create the record and insert into tmpHeap...
char *joinedRec = new char[out.recLen];
MakeNewRecord(joinedRec, leftRec, rightRec, left, right);
RecordID insertedRid;
Status tmpStatus = tmpHeap->InsertRecord(joinedRec, out.recLen, insertedRid);
if (tmpStatus != OK) {
std::cerr << "Failed to insert tuple into output heapfile." << std::endl;
return FAIL;
}
delete [] joinedRec;
}
}
delete [] rightRec;
delete rightScan;
}
out.file = tmpHeap;
delete leftScan;
delete [] leftRec;
return OK;
}
//---------------------------------------------------------------
// BlockNestedLoop::Execute
//
// Input: left - The left relation to join.
// right - The right relation to join.
// Output: out - The relation to hold the ouptut.
// Return: OK if join completed succesfully. FAIL otherwise.
//
// Purpose: Performs a block nested loops join on the specified relations.
// You can find a specification of this algorithm on page 455. You should
// choose the smaller of the two relations to be the outer relation, but you
// should make sure to concatenate the tuples in order <left, right> when
// producing output. The block size can be specified in the constructor,
// and is stored in the variable blockSize.
//---------------------------------------------------------------
Status BlockNestedLoops::Execute(JoinSpec& left, JoinSpec& right, JoinSpec& out) {
JoinMethod::Execute(left, right, out);
Status s;
HeapFile* tmpHeap = new HeapFile(NULL, s);
if (s != OK) {
std::cout << "Creating new Heap File Failed" << std::endl;
return FAIL;
}
Scan * leftScan = left.file->OpenScan(s);
if (s != OK) {
std::cout << "Open scan left failed" << std::endl;
return FAIL;
}
Scan * rightScan = right.file->OpenScan(s);
if (s != OK) {
std::cout << "Open scan left failed" << std::endl;
return FAIL;
}
RecordID leftRid, rightRid, rightFirstRid, outRid;
// array to hold the "block" in memory
char* blockArray = new char[left.recLen * blockSize];
int blockArraySize = 0; // size in case of half full block
int* leftCurrRec = (int *)blockArray;
int* leftRec = new int[left.numOfAttr];
int* rightRec = new int[right.numOfAttr];
int leftRecLen = left.recLen;
int rightRecLen = right.recLen;
char* newRec = new char[left.recLen + right.recLen];
rightFirstRid = rightScan->currRid;
Status st = OK;
while (true) {
// fill the block with as many records as possible
if (blockArraySize < blockSize) {
st = leftScan->GetNext(leftRid, (char *)leftRec, leftRecLen);
if (st != DONE) {
memcpy(blockArray + left.recLen * blockArraySize, leftRec, left.recLen);
blockArraySize++;
continue;
}
}
// scan through the right, and scan the block in memory for joins
while (rightScan->GetNext(rightRid, (char *)rightRec, rightRecLen) != DONE) {
for (int j = 0; j < blockSize; j++) {
if (j >= blockArraySize) {
break;
}
leftCurrRec = (int *) (blockArray + left.recLen * j);
if (leftCurrRec[left.joinAttr] == rightRec[right.joinAttr]) {
MakeNewRecord(newRec, (char *)leftCurrRec, (char *)rightRec, left, right);
tmpHeap->InsertRecord(newRec, left.recLen + right.recLen, outRid);
}
}
}
rightScan->MoveTo(rightFirstRid);
blockArraySize = 0;
if (st == DONE) {
break;
}
}
out.file = tmpHeap;
//std::cout << "NUM BNL: " << tmpHeap->GetNumOfRecords() << std::endl;
delete leftScan;
delete rightScan;
delete blockArray;
delete leftRec;
delete rightRec;
delete newRec;
return OK;
}
