Hannu Krosing wrote:
> > > pass 3: clean heap based on ctid from pass 1
> > >
> > > If yo do it this way, you dont need to invent new data structures to
> > > pass extra info about CITC internals to passes 2 and 3
> > >
> > > On more thing - when should free space map be notified about free space
> > > in pages with CITC chains ?
> >
> > Uh, well, I am thinking we only free CITC space when we are going to use
> > it for an UPDATE, rather than free things while doing an operation. It
> > is good to keep the cleanup overhead out of the main path as much as
> > possible.
>
> So vacuum should only remove dead CITC chains and leave the ones with
> live tuples to CITC internal use ?
Yes, it has to. What else would it do? Add index entries?
> That would also suggest that pages having live CITC chains and less than
> N% of free space should mot be reported to FSM.
Parts of the CITC that are not visible can be used for free space by
vacuum, but the visible part is left alone.
-- Bruce Momjian bruce@momjian.us EnterpriseDB http://www.enterprisedb.com
+ If your life is a hard drive, Christ can be your backup. +