Re: [Firebird-devel] non-transportable backup using without "-seservice_mgr" results in an backup file ~50% larger than the source database

[Dmitry Y. <fir...@ya...>]

Alex,

> The question is - are there any requirements in our API to what is
> placed in the message buffer as a data for varchar field with zero
> length? Should it be NULLs or may it be garbage?

I believe garbage is acceptable, not only for zero-length strings but 
also for NULLs (as we have an indicator stored separately). Although I 
remember a hack we have regarding blobs: NULL blob must have zero blob 
id, otherwise some applications started to work unpredictably, so we may 
be sure that some applications ignore our API rules :-)

But nothing prevents us from choosing the way which is better in 
practice. You know that any record buffer is initially zapped with 
zeroes to allow better compression later. So we may do the same for the 
message buffers, unless it's proven to be too much expensive (as the 
message processing is mostly CPU bound).


Dmitry