Re: Proposal: PageLayout footprint

Heikki Linnakangas napsal(a):
> Zdenek Kotala wrote:
>> Current content of control file is insufficient to check if database 
>> is compatible with postgres server. 
> 
> It is? Do you have an example of where it's insufficient?
> 

Current control file contain following information (related to page layout):

maxAlign
blcksz
toast_max_chunk_size

But you don't have control how aligned is each member of data structure.

By my opinion -fipa-struct-reorg GCC option could break structure. And maybe 
there are more compiler magic switches and optimization on different platforms 
which can modify structure alignment or member order. It probably does not 
happen often but footprint should protect people to shot himself.
Zdenek

PS: And of course toast_max_chunk_size is not insufficient as well. There are 
more constants like MaxHeapTupleSize and so on, but it is different story.