Re: HOT chain validation in verify_heapam()

On Wed, Sep 7, 2022 at 2:49 AM Robert Haas <robertmhaas(at)gmail(dot)com> wrote:

>
> But here's one random idea: add a successor[] array and an lp_valid[]
> array. In the first loop, set lp_valid[offset] = true if it passes the
> check_lp() checks, and set successor[A] = B if A redirects to B or has
> a CTID link to B, without matching xmin/xmax. Then, in a second loop,
> iterate over the successor[] array. If successor[A] = B && lp_valid[A]
> && lp_valid[B], then check whether A.xmax = B.xmin; if so, then
> complain if predecessor[B] is already set, else set predecessor[B] =
> A. Then, in the third loop, iterate over the predecessor array just as
> you're doing now. Then it's clear that we do the lp_valid checks
> exactly once for every offset that might need them, and in order. And
> it's also clear that the predecessor-based checks can never happen
> unless the lp_valid checks passed for both of the offsets involved.
>
>
ok, I have introduced a new approach to first construct a successor array
and then loop over the successor array to construct a predecessor array.

--
Regards,
Himanshu Upadhyaya
EnterpriseDB: http://www.enterprisedb.com