//--------------------------------------------------------------------
// BufMgr::FlushPage
//
// Input : pid - page id of a particular page
// Output : None
// Purpose : Flush the page with the given pid to disk.
// Condition: The page with page id = pid must be in the buffer,
// and is not pinned. pid cannot be INVALID_PAGE.
// PostCond : The page with page id = pid is written to disk if it's dirty.
// The frame where the page resides is empty.
// Return : OK if operation is successful. FAIL otherwise.
//--------------------------------------------------------------------
Status BufMgr::FlushPage(PageID pid)
{
//std::cout << "Flush Page" << pid << std::endl;
////std::cout << "Flush Page " << pid << std::endl;
int frameIndex = FindFrame(pid);
if (frameIndex == INVALID_FRAME) return FAIL;
Frame* targetFrame = &frames[frameIndex];
if(!targetFrame->IsValid() || !targetFrame->NotPinned()) return FAIL;
if (targetFrame->IsDirty()){
if (targetFrame->Write() != OK) return FAIL;
numDirtyPageWrites++;
}
replacer->RemoveFrame(targetFrame->GetPageID());
targetFrame->EmptyIt();
//std::cout << "Flush OK " << std::endl;
return OK;
}
Status BufMgr::FlushAllPages()
{
//std::cout << "Flush all " << std::endl;
bool failedOnce = false;
Frame* currFrame;
for (int iter = 0; iter < numFrames; iter++) {
currFrame = &frames[iter];
if (currFrame->IsValid()) {
// Check that the frame is not pinned
if (!currFrame->NotPinned()){
failedOnce = true;
}
if (currFrame->IsDirty()){
if (currFrame->Write() != OK) failedOnce = true;
numDirtyPageWrites++;
}
replacer->RemoveFrame(currFrame->GetPageID());
currFrame->EmptyIt();
}
}
return (failedOnce) ? FAIL : OK;
}
