Re: pgsql: Invent PageIndexTupleOverwrite, and teach BRIN and GiST to use i

Andrew Borodin <borodin(at)octonica(dot)com> writes:
> 2016-09-10 3:02 GMT+05:00 Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>:
>> Invent PageIndexTupleOverwrite, and teach BRIN and GiST to use it.

> This commit changes shape of WAL records of GiST and BRIN, but does
> not bump XLOG_PAGE_MAGIC. Is it for a reason?

Yeah, I explained it in part of the commit message you didn't quote:

Note that this patch causes a rather subtle WAL incompatibility: the
physical page content change represented by certain WAL records is now
different than it was before, because while the tuples have the same
itempointer line numbers, the tuples themselves are in different places.
I have not bumped the WAL version number because I think it doesn't matter
unless you are trying to do bitwise comparisons of original and replayed
pages, and in any case we're early in a devel cycle and there will probably
be more WAL changes before v10 gets out the door.

regards, tom lane