How to identify the unused stats in a query.

Database

How to identify the unused stats in a query.

Hi ,

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? 

Thanks,

Sreedahr.

2 REPLIES

Re: How to identify the unused stats in a query.

Collecting stats on all columns unneccesarily does not make sense.

I suggest you refer to this similar discussion.

http://teradataforum.com/teradata/20121106_093640.htm

Unused  stats maybe you can compare  pdcr hst logs,tbl infos and get what was not used.

Re: How to identify the unused stats in a query.

Hi Sreedhar,

You can collect stats on the index columns & join columns. It's not necessary to collect stats on all the columns in a table.