"Zeugswetter Andreas ADI SD" <[EMAIL PROTECTED]> writes:
> ...This looks like a problem, since we might end up with a page filled with
> LP_DEAD slots, that all have no visibility info and can thus not be
> cleaned by vacuum.
No, it's the other way round: an LP_DEAD item pointer can *always* be
cl
On 9/13/07, Zeugswetter Andreas ADI SD <[EMAIL PROTECTED]>
wrote:
>
>
> > The COLD updated (old) tuple would be pruned to dead line pointer
> > once the tuple becomes DEAD. Normally that would let us reuse the
> > tuple storage for other purposes. We do the same for DELETEd tuples.
>
> Oh, I though
> The COLD updated (old) tuple would be pruned to dead line pointer
> once the tuple becomes DEAD. Normally that would let us reuse the
> tuple storage for other purposes. We do the same for DELETEd tuples.
Oh, I thought only pruned tuples from HOT chains can produce a
"redirect dead" line point
On 9/13/07, Zeugswetter Andreas ADI SD <[EMAIL PROTECTED]>
wrote:
>
>
> > CREATE TABLE test (a int, b char(200));
> > CREATE UNIQUE INDEX testindx ON test(a);
> > INSERT INTO test VALUES (1, 'foo');
> >
> > Now, if we repeatedly update the tuple so that each update is a
> > COLD update, we would bl
> CREATE TABLE test (a int, b char(200));
> CREATE UNIQUE INDEX testindx ON test(a);
> INSERT INTO test VALUES (1, 'foo');
>
> Now, if we repeatedly update the tuple so that each update is a
> COLD update, we would bloat the page with redirect-dead line pointers.
Um, sorry for not understanding,
On 9/13/07, Tom Lane <[EMAIL PROTECTED]> wrote:
>
>
>
> The difficulty with this is having to be 100% confident that noplace in
> the system tries to dereference a TID without checking that the line
> number (offset) is within range. At one time that was demonstrably
> not so. I think we've clean
"Pavan Deolasee" <[EMAIL PROTECTED]> writes:
> How about passing a boolean to PageRepairFragmentation to
> command it to reclaim unused line pointers ?
The difficulty with this is having to be 100% confident that noplace in
the system tries to dereference a TID without checking that the line
numbe
We know that HOT can cause line pointer bloat because of redirect dead
line pointers. In the worst case there could be MaxHeapTuplesPerPage
redirect-dead line pointers in a page. VACUUM can reclaim these line
pointers and mark them ~LP_USED (what is now called LP_UNUSED).
But we don't reclaim the
