Day: January 11, 2019

A client asked about why it takes 14.96 seconds for below sql(1):

SQL>select * from dba_tables;
Elapsed: 00:00:14.96

While it takes only 0.59 second for this sql(2):

SQL>select count(*) from dba_tables;
Elapsed: 00:00:00.59

Let’s compare the tkprof summary from sql tracing for those two sqls: