LOCK.tag(figuring out granularity of lock)
following is taken from postgresql-7.3.2/src/backend/storage/lmgr/readme:
"If we are setting a table level lock
both the blockId and tupleId (in an item pointer this is called
the position) are set to invalid, if it is a page level lock the
blockId is valid, while the tupleId is still invalid. Finally if
this is a tuple level lock (we currently never do this) then both
the blockId and tupleId are set to valid specifications. "
how do we check whether blockId and tupleId of LOCK.tag are valid or
invalid?
is blockId same as tag.objId.blkno? what field in LOCK.tag is tupleId?
thanks
jenny
_________________________________________________________________
Protect your PC - get McAfee.com VirusScan Online
http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963
"Jenny -" <nat_lazy@hotmail.com> writes:
how do we check whether blockId and tupleId of LOCK.tag are valid or
invalid?
Look at how LockRelation and LockPage (in
src/backend/storage/lmgr/lmgr.c) set up the tags --- it might be clearer
then.
regards, tom lane