void ResourceNode::wakeAndDetach()
{
TransactionNode *txn;
set<RGNode *>::iterator sit;
set<RGNode *>::iterator dummy_sit;
for (sit = in.begin(); sit != in.end(); ) {
txn = dynamic_cast<TransactionNode *>(*sit);
txn->wake();
dummy_sit = ++sit;
removeInEdge(txn);
sit = dummy_sit;
}
in.clear();
}
LBIDResourceGraph::~LBIDResourceGraph()
{
std::map<VER_t, TransactionNode *>::iterator tnit;
RNodes_t::iterator rit;
TransactionNode *txnNode;
for (tnit = txns.begin(); tnit != txns.end(); ) {
txnNode = (*tnit).second;
if (txnNode->sleeping()) {
txnNode->die();
txnNode->wake();
++tnit;
}
else {
txns.erase(tnit++);
delete txnNode;
}
}
for (rit = resources.begin(); rit != resources.end(); ) {
delete *rit;
resources.erase(rit++);
}
}
void LBIDResourceGraph::releaseResources(VER_t txn)
{
/*
get transaction node
get all inbound nodes
detach them and wake all txns on the in-edges
delete the resource nodes
get all outbound nodes (this can happen if a rollback comes in while blocked)
detach them
if txnNode isn't sleeping,
delete the transaction node
else
mark it dead and wake it
*/
TransactionNode *txnNode;
ResourceNode *rNode;
map<VER_t, TransactionNode *>::iterator it;
set<RGNode *>::iterator sit;
set<RGNode *>::iterator dummy_sit;
it = txns.find(txn);
if (it == txns.end())
return;
txnNode = (*it).second;
for (sit = txnNode->in.begin(); sit != txnNode->in.end(); ) {
rNode = dynamic_cast<ResourceNode *>(*sit);
dummy_sit = ++sit;
rNode->wakeAndDetach();
txnNode->removeInEdge(rNode);
resources.erase(rNode);
delete rNode;
sit = dummy_sit;
}
for (sit = txnNode->out.begin(); sit != txnNode->out.end(); )
{
rNode = dynamic_cast<ResourceNode *>(*sit);
dummy_sit = ++sit;
txnNode->removeOutEdge(rNode);
sit = dummy_sit;
}
if (txnNode->sleeping()) {
txnNode->die();
txnNode->wake();
}
else {
txns.erase(txn);
delete txnNode;
}
}
/*
0 = OK
1 = transaction node was not found on wake
-1 = deadlock detected, transaction node destroyed and resources released
mutex should be slavelock
*/
int LBIDResourceGraph::reserveRange(LBID_t start, LBID_t end, VER_t txn,
boost::mutex &mutex)
{
TransactionNode *txnNode;
map<VER_t, TransactionNode *>::iterator it;
/*
look for existing transaction node T
- make one if necessary
connectResources();
checkDeadlock();
while (txnNode.out.size() > 0)
block on T's condvar
connectResources();
checkDeadlock();
}
*/
it = txns.find(txn);
if (it == txns.end()) {
txnNode = new TransactionNode(txn);
txns[txn] = txnNode;
}
else
txnNode = (*it).second;
connectResources(start, end, txnNode);
// "If txnNode is waiting on at least one LBID range..."
while (txnNode->out.size() > 0) {
// make sure there's no deadlock before blocking
if (checkDeadlock(*txnNode)) {
// releaseResources(txn);
return ERR_DEADLOCK;
}
#ifdef BRM_VERBOSE
cerr << " RG: sleeping transaction " << txn << endl;
set<RGNode *>::iterator sit;
cerr << " waiting on: " << endl;
for (sit = txnNode->out.begin(); sit != txnNode->out.end(); sit++) {
ResourceNode *rn = dynamic_cast<ResourceNode *>(*sit);
cerr << hex << rn << dec << " " << rn->lbid() << endl;
}
#endif
txnNode->sleep(mutex);
#ifdef BRM_VERBOSE
cerr << " RG: txn " << txn << " is awake" << endl;
#endif
if (txnNode->dead()) {
txns.erase(txn);
delete txnNode;
return ERR_KILLED;
}
// attempt to grab remaining resources
connectResources(start, end, txnNode);
}
// txn has all requested LBID ranges
return ERR_OK;
}
