Re: Configuring BLCKSZ and XLOGSEGSZ (in 8.3)

Peter Eisentraut <peter_e@gmx.net> writes:
> I don't doubt that there may be a positive effect from increasing the 
> block size.  But we haven't seen any analysis of why that might be.

It seems at least as likely that increased block size would *decrease*
performance by requiring even small writes to do more physical I/O.
This applies to both data files and xlog.

But the real issue here is whether there are grounds for supporting
run-time changes in the block size.  AFAICS the evidence for supporting
even compile-time changes is pretty weak; why should we take the likely
complexity and performance costs of making it run-time changeable?
        regards, tom lane