On Jan 2, 2008 6:24 PM, Martijn van Oosterhout <[EMAIL PROTECTED]> wrote:
> On Wed, Jan 02, 2008 at 04:46:11PM +0530, Gokulakannan Somasundaram wrote: > > > All indexes are done by user-defined functions, even b-trees. People > can > > > make their own b-tree indexes by defining an operator class. Note that > > > "user-defined" is this case means anything called via the fmgr > > > interface. > > > > Again, i think i have one more wrong understanding. My understanding is, > > We are discussing about user-defined functions because, they might be > > actually be mutable functions, but the user might have classified as > > immutable. > > This is where it gets a bit beyond by depth, so someone may have to > correct me. The point is that during the recovery the system is not yet > fully running and not everything works yet. For example, what happens > if the system crashed halfway through updating a page in pg_proc and > that page needs to be recovered from WAL. Yet to insert into the index > you need to be able to read pg_am, pg_amproc, pg_proc at least, > probably more. > > The point being, you can't rely on anything except WAL during recovery. > > Thanks a lot for the nice explanation. That was something new for me....:(( -- Thanks, Gokul.
