About database indexes 1

Why are indexes used? Indexes are used to increase the performance of retrieval. We can make use of one or more rows in order to create the index. Indexes can increase the performance of retrieval and slows down the performance of insertion into the tables. Who is responsible for updating the indexes? Oracle automatically maintains ...

SQL Trace and TKPROF

TKPROF stands for transient kernel profiler.Enabling SQL TRACETo be able to use TKPROF, you must first enable sql trace. This can be done for either the instance or the session. If you want to change it for the entire instance, set sql_trace=true into theinit.ora file and restart the instance. However, usually, you’ll want to turn on sql trace for a particular session only. ...

About tablespaces

A tablespace is a logical storage unit within an Oracle database. It is logical because a tablespace is not visible in the file system of the machine on which the database resides. A tablespace, in turn, consists of at least one datafile which, in turn, are physically located in the file system of the server. Btw, a datafile belongs ...

Exploring initialization parameters

The initialization parameters can be set in the init.ora file. There are two common ways to find out to what value an initialization parameter is set: show parameter <param_name> in sql*plus, or select value from v$parameter where name = lower(‘param_name’) The parameters can be changed for the currently connectedsession with a alter session set … command. If a parameter should be set in another session,dbms_system.set_bool_param_in_session ordbms_system.set_int_param_in_session can ...

Checking on the Listener

If users can not connect to the database, how can you see if the listener is actually running? The best way is to issue the command lsnrctl status. Another way is to look for the process to see if it is running (either in Windows Task Manager or by issuing the unix command ps-ef). We ...
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