Explain Plan in Teradata

Explain plan is the step-by-step English translation of a query plan generated by the parsing engine. Explain plan can give you a clear picture the way optimizer will execute a query. It is a good practice to analyze the explain … Read more »

Teradata Volatile Table

Teradata Volatile tables act like a normal Teradata table but are volatile in nature. What does that mean? The Volatile tables in Teradata are created by the user and used only for the duration they are logged into the Teradata … Read more »

Temporary Table in Teradata

Teradata provides the flexibility to use three types of temporary table which helps user to accomplish their work more easily. This kind of table is temporary to the database that means tables are not going to store permanently in the … Read more »

Pseudo Lock in Teradata

When user tries to access data from any table Teradata applies read lock on that table. We can see from the explain plan of the query- Explain sel * from mydb.teradatapoint;   1) First, we lock a distinct mydb.”pseudo table” … Read more »

Teradata Locks

All the objects in the database are shared among variety of users who are accessing the data in parallel. For example, one user is updating a table and if another user tries to access that table at the same time, … Read more »

Recovery Journal in Teradata

Down-AMP Recovery Journal:- Recovery journal provides the capability to continue normal write operation like insert, update, create and delete on a table even if a logical AMP goes down in the same cluster. Suppose we have activated the fallback option … Read more »

Permanent Journal in Teradata

The permanent journal in Teradata provides the capability to capture the snapshot of  the  table/tables before and after applying changes using DML statements like insert, delete and update. Unlike transient journal which capture the snapshot of table before applying  changes … Read more »

NOPI (No primary index) Table in Teradata

As the name suggests, No primary index table means there will be no primary index defined on Teradata table. This feature has been introduced in V2R13 release.  The main purpose of this feature which allows us to create tables with … Read more »


We have two types of tables in Teradata, SET and Multiset table and the main difference of these table is SET table doesn’t allow duplicate row whereas Multiset table allows it, as below: A set table does not allow any … Read more »

Teradata Space

There are mainly three types of spaces in Teradata. These are: Permanent Space. Spool Space. Temporary Space. Let us understand in brief about them.   PERMANENT SPACE (Perm Space):- This is the space where objects such as databases, users, tables, … Read more »