Welcome To Datawarehouse World

What is a deadlock and what is a live lock? How will you go about resolving deadlocks in SQL Server Deadlock is a situation when two processes, each having a lock on one piece of data, attempt to acquire a lock on the other’s piece. Each process would wait indefinitely for the other to release the lock, unless one of the user processes is terminated. SQL Server detects deadlocks and terminates one user’s process. A livelock is one, where a  request for an exclusive lock is repeatedly denied because a series of overlapping shared locks keeps interfering. Sql server detects the situation after four denials and refuses further shared locks. A livelock also occurs when read transactions monopolize a table or page, forcing a write transaction to wait indefinitely.  

How to copy the unix directory from one server to other server: Command : scp -r source path @targetmachine:target path

Select Cust_Id, Cust_NAME, Quantity, COUNT (*)    FROM Customer GROUP BY Cust_Id, Cust_NAME, Quantity HAVING COUNT (*) >1;

What is the difference between Minus and Intersect? What is their use in ETL testing? Intersect operation is used to combine two SELECT statements, but it only returns the records which are common from both SELECT statements. In case of Intersect, the number of columns and datatype must be same. select * from First INTERSECT select * from second Minus operation combines result of two Select statements and return only those result which belongs to first set of result. A Minus query looks as follows − select * from First MINUS select * from second If you perform source minus target and target minus source, and if the minus query returns a value, then it should be considered as a case of mismatching rows. If the minus query returns a value and the count intersect is less than the source count or the target table, then the source and target tables contain duplicate rows.  

Advantages of Catalog Vacuuming.         -           This process will remove the unneeded rows (shrink process) from system tables and compact disk space to enable faster system table scanning. -           Auto catalog vacuuming process: -           When Netezza server is running, it checks for database system table growth above 120 KB (checks every 60 secs) and invokes system table vacuum if it grows above 128 KB. (Referred from IBM support portal).

How we can able to check the netezza active server hostname [whether primary host or secondary host]?...   Query: select * from _t_environ;