RE: WAL & SHM principles

> It is possible to build a logging system so that you mostly don't care
> when the data blocks get written; a particular data block on disk is 
> considered garbage until the next checkpoint, so that you 

How to know if a particular data page was modified if there is no
log record for that modification?
(Ie how to know where is garbage? -:))

> might as well allow the blocks to be written any time,
> even before the log entry.

And what to do with index tuples pointing to unupdated heap pages
after that?

Vadim