Re: WIP: Pg_upgrade - page layout converter (PLC) hook

Josh Berkus napsal(a):
> Zdenek,
> 
>> Unfortunately, this approach does not work between layout 3 and 4. It
>> works only for heap on platfrom with maxallign=4.
>>
>> The main problem is that PageHeader has been extended to 24 bytes and it
>> requires reindexing, TOAST chunk resizing, converted tuples does not fit
>> on page on platform where maxallign=8.
>>
>> I'm now working on offline conversion method.
> 
> Hmmm.  I thought we determined earlier that the use case for *offline* 
> binary conversion was rather limited.  It would have to be 10x faster than 
> dump/reload to be worthwhile.  Do you think this is possible?
> 

It is difficult to say without prototype. However, binary conversion can be 
performed without (or minimal) WAL logging and without sync. I think async write  is a big improvement. And there is
notproblem convert tables in parallel mode.
 
And of course you don't need bin<->text<->bin conversion. Unfortunately reindex 
is necessary in both cases.
Zdenek