Re: [Firebird-devel] [SPAM 5] Re: Firebird Transaction ID limit solution - Email found in subject

[Alexander P. <pes...@ma...>]

В Пт., 30/12/2011 в 23:10 +0100, Kjell Rilbe пишет:
> Den 2011-12-30 21:43 skrev Leyne, Sean såhär:
> > Dmitry,
> >
> >> Trunk is the ongoing development branch (formerly known as HEAD in CVS),
> >> i.e. transaction IDs are already unsigned long in FB 3.0.
> > Although this would mean a further ODS change as well as an increase in overhead associated with all rows, perhaps the ODS size should be increased from 4 bytes to 5 bytes to remove any possible likelihood of overflowing the max value (=256 transactions per sec, continuously for over 136 years!)
> Who knows what will happen within only 5-10 years? Perhaps in five 
> years, it will be common with systems running a few thousand 
> transactions per second? In that case 40 bits will only suffice for 
> about 11 years (3000 trans/sec).
> 
> If such a "big" change is to be made I suggest to make it at least 48 
> bits, and why not 64 bits while we're at it? 

This will make each version of the record (not the record- but EACH
version of it) 4 bytes longer. For table with small records that means
severe performance degradation.