/*
* Run the redo phase of ARIES.
* If the StorageEngine stops responding, return false.
* Else when redo phase is complete, return true.
*/
bool LogMgr::redo(vector <LogRecord*> log)
{
TxType tType;
int lsn, pageID, offset, nextLsn;
string afterImage;
for(auto it = log.begin(); it != log.end(); it++)
{
LogRecord *logPointer = *it;
tType = logPointer->getType();
lsn = logPointer->getLSN();
if ( tType == UPDATE )
{
UpdateLogRecord * updateLogPointer = dynamic_cast<UpdateLogRecord *>(logPointer);
pageID = updateLogPointer->getPageID();
afterImage = updateLogPointer->getAfterImage();
offset = updateLogPointer->getOffset();
}
else if ( tType == CLR )
{
CompensationLogRecord * compensationLogPointer = dynamic_cast<CompensationLogRecord *>(logPointer);
pageID = compensationLogPointer->getPageID();
afterImage = compensationLogPointer->getAfterImage();
offset = compensationLogPointer->getOffset();
}
if ( dirty_page_table.find(pageID) == dirty_page_table.end() )
{
continue;
}
if( dirty_page_table[pageID] <= lsn && se->getLSN(pageID) < lsn )
{
if( !(se->pageWrite(pageID, offset, afterImage, lsn)) )
{
return false;
}
}
}
vector <int> txToErase;
for ( auto it = tx_table.begin(); it != tx_table.end(); it++ )
{
if( it->second.status == C && it->first != NULL_TX )
{
nextLsn = se->nextLSN();
logtail.push_back(new LogRecord(nextLsn, it->second.lastLSN, it->first, END));
txToErase.push_back(it->first);
}
}
for ( int i = 0; i < txToErase.size(); i++ )
{
tx_table.erase(txToErase[i]);
}
return true;
}
/*
* Run the redo phase of ARIES.
* If the StorageEngine stops responding, return false.
* Else when redo phase is complete, return true.
*/
bool LogMgr::redo(vector <LogRecord*> log){
//first find the oldest update in the dirty-table
int oldest_lsn = INT_MAX;
map<int,int>::iterator it;
for(it = dirty_page_table.begin(); it!=dirty_page_table.end(); it++){
if(it->second < oldest_lsn){
oldest_lsn = it->second;
}
}
// iterate through the log
for(int i = oldest_lsn; i<log.size() ; i++){
TxType t = log[i]->getType();
if(t == UPDATE || t == CLR){
if(t == UPDATE){
// if this is update
UpdateLogRecord * updLog = (UpdateLogRecord * ) log[i];
int pageID = updLog->getPageID();
//check the constraint
it = dirty_page_table.find(pageID);
//if the pageID is int the dirty page
if(it !=dirty_page_table.end()){
// check if the reclsn is samller then the lsn
int lsn = updLog->getLSN();
int reclsn = dirty_page_table[pageID];
if(reclsn <= lsn){
//check the page lsn is samller than the lsn
int pageLSN = se->getLSN(pageID);
if(pageLSN < lsn){
// redo things
if(se->pageWrite(pageID,updLog->getOffset(),updLog->getAfterImage(),lsn)){
}else{
return false;
}
}
}
}
}
else{
// if this is clr
CompensationLogRecord * clrLog = (CompensationLogRecord *) log[i];
int pageID = clrLog->getPageID();
it = dirty_page_table.find(pageID);
if(it != dirty_page_table.end()){
int lsn = clrLog->getLSN();
int reclsn = dirty_page_table[pageID];
if(reclsn <= lsn){
int pageLSN = se->getLSN(pageID);
if(pageLSN < lsn){
if(se->pageWrite(pageID,clrLog->getOffset(),clrLog->getAfterImage(),lsn)){
}else{
return false;
}
}
}
}
}
}
}
// write end type record for C type
map<int ,txTableEntry>::iterator tit;
for(tit = tx_table.begin(); tit != tx_table.end(); tit++){
if(tit->second.status == C){
LogRecord* eLR = new LogRecord(se->nextLSN(),tit->second.lastLSN,tit->first,TxType::END);
logtail.push_back(eLR);
tx_table.erase(tit);
}
}
return false;
}
