I’ve just received an email asking (yet again) a question about counting the number of rows in a table.
We have a large table with a CLOB column, where the CLOB occupies 85% storage space.
when we use select count(*) from , the DBA says that you should not use count(*) as it uses all columns and as this table contains CLOB it results in high CPU usage, where as if we use count(rowid), this brings us faster and same result.