On 2015-07-15 12:48:40 +0530, Amit Kapila wrote:
> If during scan of a relation, after doing checksum for half of the
> blocks in relation, system crashes, then in the above scheme a
> restart would need to again read all the blocks even though some
> of the blocks are already checksummed in previous cycle, this is
> okay if it happens for few small or medium size relations, but assume
> it happens when multiple large size relations are at same state
> (half blocks are checksummed) when the crash occurs, then it could
> lead to much more IO than required.
I don't think this is worth worrying about. If you crash frequently
enough for this to be a problem you should fix that. Adding complexity
for such an uncommon case spreads the cost to many more people.