/**
* User should call this method if s/he needs to delete a page. this routine will call DB to
* deallocate the page.
*
* @param globalPageId the page number in the data base.
* @exception InvalidBufferException if buffer pool corrupted.
* @exception ReplacerException if there is a replacer error.
* @exception HashOperationException if there is a hash table error.
* @exception InvalidFrameNumberException if there is an invalid frame number.
* @exception PageNotReadException if a page cannot be read.
* @exception BufferPoolExceededException if the buffer pool is already full.
* @exception PagePinnedException if a page is left pinned.
* @exception PageUnpinnedException if there is a page that is already unpinned.
* @exception HashEntryNotFoundException if there is no entry of page in the hash table.
* @exception IOException if there is other kinds of I/O error.
* @exception BufMgrException other error occured in bufmgr layer
* @exception DiskMgrException other error occured in diskmgr layer
*/
public void freePage(PageId pageId)
throws InvalidBufferException, ReplacerException, HashOperationException,
InvalidFrameNumberException, PageNotReadException, BufferPoolExceededException,
PagePinnedException, PageUnpinnedException, HashEntryNotFoundException, BufMgrException,
DiskMgrException, IOException {
BufMgrFrameDesc frame = pageTable.get(pageId);
if (frame != null) {
int pinCount = frame.getPinCount();
if (pinCount > 1) {
throw new PagePinnedException(null, "BufrMgr::freePage: page to be freed not loaded");
} else {
if (pinCount == 1) {
frame.unpin();
replacer.unpin(frame.getFrameNumber());
}
// remove from pagetable/frametable
pageTable.remove(pageId);
// add it to empty list
frameTable[frame.getFrameNumber()] = null;
replacer.free(frame.getFrameNumber());
// free it on disk
try {
SystemDefs.JavabaseDB.deallocate_page(pageId);
} catch (Exception e1) {
throw new DiskMgrException(
e1, "BUFMGR::freepage failed " + "after pinPage failed and deallocate page failed");
}
}
} else {
// free it on disk
try {
SystemDefs.JavabaseDB.deallocate_page(pageId);
} catch (Exception e1) {
throw new DiskMgrException(e1, "BUFMGR::freepage failed");
}
}
}
/**
* To unpin a page specified by a pageId. If pincount>0, decrement it and if it becomes zero, put
* it in a group of replacement candidates. if pincount=0 before this call, return error.
*
* @param globalPageId_in_a_DB page number in the minibase.
* @param dirty the dirty bit of the frame
* @exception ReplacerException if there is a replacer error.
* @exception PageUnpinnedException if there is a page that is already unpinned.
* @exception InvalidFrameNumberException if there is an invalid frame number .
* @exception HashEntryNotFoundException if there is no entry of page in the hash table.
*/
public void unpinPage(PageId pageId, boolean dirty)
throws ReplacerException, PageUnpinnedException, HashEntryNotFoundException,
InvalidFrameNumberException {
BufMgrFrameDesc frame = pageTable.get(pageId);
if (frame != null) {
int pinCount = frame.getPinCount();
if (pinCount == 0) {
throw new PageUnpinnedException(
null, "BufrMgr::unPinPage: page to be unpinned is already unpinned");
} else {
frame.unpin();
if (frame.getPinCount() == 0) replacer.unpin(frame.getFrameNumber());
}
frame.setDirtybit(dirty);
} else {
throw new HashEntryNotFoundException(
null, "BufrMgr::unPinPage: page to be unpinned not loaded");
}
}
