Can anyone tell me, if i have collected stats on every column of all the tables, does this impact in query performance?
if so, how to identify the unused stats ? so that we can drop them to improve perfomance.
example: in our environment , if the table contains 6 columns, then we have collected stats on all the 6 columns + * and the partition(if it is a partition table), is this a bad idea to collect stats on all these columns of a table?
Collecting stats on all columns unneccesarily does not make sense.
I suggest you refer to this similar discussion.
Unused stats maybe you can compare pdcr hst logs,tbl infos and get what was not used.
You can collect stats on the index columns & join columns. It's not necessary to collect stats on all the columns in a table.