Materialized View Initial Creation vs Complete Refresh - MAJOR differences
641539Jun 17 2008 — edited Jun 26 2008Hi All,
I am currently in the process of setting up MV's for replication via a DBLink and have noticed something that I find quite odd. Basically If I create an MV I get v. large differences than when I do a complete refresh on the same MV after the initial "load". Actual stats are shown below :
Action TimeTaken Undo Reqd (Bytes)
Initial Load 00:01:07 37254998
Complete Refresh 00:02:41 463919012
Question is why does a complete refresh require 12x the amount of Undo than the creation of the MV? I though tit would be roughly the same or at most twice as much?
The Instance is only being used by myself so no other processes are causing this difference and this can be reproduced. Undo calculated from V$ROLLSTAT.
Thanks
MH