Re: Block-level CRC checks

* Jonah H. Harris <jonah.harris@gmail.com> [081002 12:43]:
> > #define write(fd, buf, count) buffer_crc_write(fd, buf, count)
>
> I certainly wouldn't interpose the write() call itself; that's just
> asking for trouble.

Of course not, that was only to show that whatever you currenlty pritect
"write()" with, is valid for protecting the buffer+write.

> > But I thought you didn't really care about hint-bit updates, even in the
> > current strategy... but I'm fully ignorant about the code, sorry...
>
> The current implementation does not take it into account.

So if PG currently doesn't care about the hit-bits being updated, during
the write, then why should introducing a double-buffer introduce the a
torn-page problem Tom mentions?  I admit, I'm fishing for information
from those in the know, because I haven't been looking at the code long
enough (or all of it enough) to to know all the ins-and-outs...

a.
--
Aidan Van Dyk                                             Create like a god,
aidan@highrise.ca                                       command like a king,
http://www.highrise.ca/                                   work like a slave.