Creating an index on one of my large tables takes me arounf 2 Hours.
If i create the index using Parallel 8 which will of course reduce the index creation time, and then later on once the index has been created , say i reset it back to NOPARALLEL, will there be any problem in data fetch later on. i mean any unforseen problem in future ? for ex, the standard queries might not use the index etc. etc. ?
is it safe ? because i will be doing it on the Production database.
a) your affirmation "using parallel 8 which will ** of course ** reduce the index creation time..." is NOT necessarily true : see, parallel means "I have unused resources at the moment (CPUs, memory, I/O bandwith) , and I want to have various processes doing a part of the big job each one". OF COURSE, each process WILL consume CPU, RAM & I/O, *** so *** if right now you DONīT have available resources in the machine, having even MORE processes running WILL slow you in a BIG way.
b) yes, it is safe to do it in production, I always do using PARALLEL (and NOLOGGING, for the matter) , no probs.