Archives of the TeradataForum
Message Posted: Fri, 09 Nov 2001 @ 15:35:10 GMT
| Subj: || || Re: Rehash on a restore |
| From: || || Dieter Nöth |
| ||I'm looking for someone who has some experience with doing restores after a hardware upgrade.|| |
Don't ask me ;-)
| ||Last year we did an upgrade that required a sysint (you think I'd be good t them by now). My restores took about the same
amount of time as my archives, but were running on a machine 3 times faster (1 node to 3 nodes).|| |
| ||The restores from the last upgrade had messages as follows:|| |
| ||*** Warning 3803:Table 'B_MB_DETAIL' already exists.|
NEED TO RE-HASH ROWS
STARTING TO RESTORE TABLE "HBCADM"."B_MB_DETAIL"
| ||I would have expected the same kind of message restoring from one system to another - after all they have a different hash
A different hash map, but the same hashing algorithm. When you SYSINITed, you probably used the new Universal Hash, so all rowhashes had
to be recalculated.
When you restore to a system with different AMPs, then the rowhashes stay the same, the rows are only redistributed across all AMP.