explain plan

Database
Fan

explain plan

Hi,
Where can i find a didtailed explain on the explain plan.
How tera decides when to use the index and when not?

Thanks
Ronir
1 REPLY
Enthusiast

Re: explain plan

This needs a long discussion,
but anyways if you run the explain check for words like
"By way of primary index" (rows are read using primary index column(s))
"By way of index number" (rows are read using secondary index)
"BMSMS" Bit map set manipulations .. using NUSI columns.