TERADATA REALTIME INTERVIEW QUESTIONS :
1) What is use of PPI in Teradata?
1)Range queries should not use a full Table Scan.
2)Deletions of entire partitions are fast as lightning.
3)PPI provides an excellent solution to instead of using secondary indexes
4)Tables that contain annual information should not be divided into 12 smaller tables to avoid 5)scanning full table (FTS). This can simplify the modeling and easier querying.
6)FastLoad and Multiload work with tables of the IPP, but not with all the secondary indexes.
2) what are disadvantags in PPI ?
1) A two-byte Partition number is added to the row ID and it is now called a key of the row. The two bytes per line will add Perm more space to a table.
2)Joins Non-Partitioned Tables can take more time and become more complicated for Teradata to perform.
3)Select base using the primary Index can take longer if the Partition number is not also mentioned in the WHERE clause of the query.
4)You can not have a Unique Index for the primary (UPI) if the Partition number is not at least a part of the primary Index. So you must create a Unique secondary Index to maintain uniqueness.
3) What is Volatile temporary tables in teradata?
Ans) Volatils tables sont des tables temporaires qui sont matérialisés dans la bobine et ne sont pas connus pour le dictionnaire de données.
Une table instable peut être utilisé plusieurs fois et en plus d'une instruction SQL pendant toute la durée d'une session. Cette fonctionnalité permet des requêtes supplémentaires utiliser les mêmes lignes dans la table temporaire sans nécessiter les lignes pour être reconstruite.
Tables volatils sont locales à la session et les tables sont supprimées une fois que la session est déconnectée.
SUR COMMIT PRESERVE ROWS option doit être mentionnée au moment de la création de la table. Cela signifie qu'à la fin d'une transaction, les lignes de la table volatile ne seront pas supprimés. Les informations contenues dans la table restent pendant toute la session. Utilisateurs peuvent poser des questions à la table volatile jusqu'à ce qu'ils se déconnectent. Puis la table et les données disparaissent.
4) What is global temporary tables in teradata?
Ans) Global temporary Tables are similar to the volatile tables in teradata. because they are local to a user session. However, when the table is created, the definition is stored in the data dictionary. In addition, these tables are materialized in a permanent area known as temporary space. For these reasons, global tables can survive a reboot of the system and the definition of the table will not be discarded at the end of the session. However, when a system reboots, the lines inside the global temporary Table will be deleted. Finally, the global tables require no spool space. They use the Temp.
Statistics can be collected in the two tables in the TD13 Version. Previously the Stats of collection on the tables of volatile are not allowed.
5) How will Performance improvement in Teradata?
Ans) STATS are collected on the columns used in WHERE CLAUSE the columns and join. If the STATS are collected, explain plan will show high confidence that tells the optimizer on the number of rows in the table that will help the optimizer to choose redistribution/duplication of smaller tables.
Check the join columns & where Clause if PI, if or PPI are used.
Check if the appropriate alias names are used in the join conditions.
Divide queries into subsets in the event of poor performance.
6) What IS Pseudo TableS in Teradata?
Ans) It is a false lock that is applied on the table to prevent two users to obtain locks conflict with everything-AMP applications.
PE will determine a particular amp to manage requests for lock AMP given nickname and table put lock on the table.
1) What is use of PPI in Teradata?
1)Range queries should not use a full Table Scan.
2)Deletions of entire partitions are fast as lightning.
3)PPI provides an excellent solution to instead of using secondary indexes
4)Tables that contain annual information should not be divided into 12 smaller tables to avoid 5)scanning full table (FTS). This can simplify the modeling and easier querying.
6)FastLoad and Multiload work with tables of the IPP, but not with all the secondary indexes.
2) what are disadvantags in PPI ?
1) A two-byte Partition number is added to the row ID and it is now called a key of the row. The two bytes per line will add Perm more space to a table.
2)Joins Non-Partitioned Tables can take more time and become more complicated for Teradata to perform.
3)Select base using the primary Index can take longer if the Partition number is not also mentioned in the WHERE clause of the query.
4)You can not have a Unique Index for the primary (UPI) if the Partition number is not at least a part of the primary Index. So you must create a Unique secondary Index to maintain uniqueness.
3) What is Volatile temporary tables in teradata?
Ans) Volatils tables sont des tables temporaires qui sont matérialisés dans la bobine et ne sont pas connus pour le dictionnaire de données.
Une table instable peut être utilisé plusieurs fois et en plus d'une instruction SQL pendant toute la durée d'une session. Cette fonctionnalité permet des requêtes supplémentaires utiliser les mêmes lignes dans la table temporaire sans nécessiter les lignes pour être reconstruite.
Tables volatils sont locales à la session et les tables sont supprimées une fois que la session est déconnectée.
SUR COMMIT PRESERVE ROWS option doit être mentionnée au moment de la création de la table. Cela signifie qu'à la fin d'une transaction, les lignes de la table volatile ne seront pas supprimés. Les informations contenues dans la table restent pendant toute la session. Utilisateurs peuvent poser des questions à la table volatile jusqu'à ce qu'ils se déconnectent. Puis la table et les données disparaissent.
Ans) Global temporary Tables are similar to the volatile tables in teradata. because they are local to a user session. However, when the table is created, the definition is stored in the data dictionary. In addition, these tables are materialized in a permanent area known as temporary space. For these reasons, global tables can survive a reboot of the system and the definition of the table will not be discarded at the end of the session. However, when a system reboots, the lines inside the global temporary Table will be deleted. Finally, the global tables require no spool space. They use the Temp.
Statistics can be collected in the two tables in the TD13 Version. Previously the Stats of collection on the tables of volatile are not allowed.
5) How will Performance improvement in Teradata?
Ans) STATS are collected on the columns used in WHERE CLAUSE the columns and join. If the STATS are collected, explain plan will show high confidence that tells the optimizer on the number of rows in the table that will help the optimizer to choose redistribution/duplication of smaller tables.
Check the join columns & where Clause if PI, if or PPI are used.
Check if the appropriate alias names are used in the join conditions.
Divide queries into subsets in the event of poor performance.
6) What IS Pseudo TableS in Teradata?
Ans) It is a false lock that is applied on the table to prevent two users to obtain locks conflict with everything-AMP applications.
PE will determine a particular amp to manage requests for lock AMP given nickname and table put lock on the table.
7) What are phases of MultiLoad in Teradata?
1) Preliminary phase
2)DML phase
3 )Acquisition phase
4 )Application phase
5) End phase
8)What is Fast Loads in Teradata?
9)What is Multi Load in Teradata?
10)What is Teradata Parallel Data Pump Utility in Teradata?
11) What is SLEEP command ?
12) Where is Tenacity command use ?
13) what is ORDER BY clause in Teradata?
14)howmany options available for TSA?
15)what is MultiLoad in Teradata?
16)what is SQL history in Teradata?
17)can you tell about join strategy in Teradata?
18)how can we handle nulls in Teradata?
19)what is PPI columns in teradata?
20)what is User and database in Teradata?
11) What is SLEEP command ?
12) Where is Tenacity command use ?
13) what is ORDER BY clause in Teradata?
14)howmany options available for TSA?
15)what is MultiLoad in Teradata?
16)what is SQL history in Teradata?
17)can you tell about join strategy in Teradata?
18)how can we handle nulls in Teradata?
19)what is PPI columns in teradata?
20)what is User and database in Teradata?
