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Vertica Blog

Best Practices

Display Tables Referenced by a View: Quick Tip

Jim Knicely authored this tip. Vertica 9.2 introduces the new VIEW_TABLES system table that shows details about view-related dependencies, including the table that reference a view, its schema, and owner. Helpful Link: Have fun!
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Calculate the Catalog Size in Memory on Each Node: Quick Tip

The RESOURCE_POOL_STATUS system table provides the current state of built-in and user-defined resource pools on each node, including memory usage. The METADATA built-in pool tracks memory allocated for catalog data and storage data structures. Knowing those two facts, we can calculate catalog memory usage on all nodes by querying the system table RESOURCE_POOL_STATUS for the...

Labeling Queries: Quick Tip

To quickly identify queries for profiling and debugging purposes, include the LABEL hint. Later you can search the QUERY_REQUESTS and QUERY_PROFILES systems table for the label! Helpful Links: Have fun!

Create a User Defined SQL Function to Calculate Fibonacci Numbers: Quick Tip

The Fibonacci Sequence is the series of numbers (i.e. 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, ...) where the next number in the sequence is found by taking the sum of the previous two numbers. Calculating these numbers in SQL would be a bit complicated if it were not for the “Golden...
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Calculate Future Thanksgiving Dates: Quick Tip

Jim Knicely authored this tip. In the United States, Thanksgiving is always celebrated on the fourth Thursday of November. In Canada, Thanksgiving is celebrated the second Monday in October. So that you don’t miss another holiday at home with mom, make sure to plan ahead and calculate (using SQL) future Thanksgiving dates! Helpful Links: Have...

Announcing Vertica 9.x Training: Predictive Analytics Using Machine Learning

Drea Brandford authored this post. In today’s data-driven world, creating a competitive advantage depends on your ability to transform massive volumes of data into meaningful insights. Companies that use advanced analytics and machine learning are twice as likely to be top quartile financial performers, and three times more likely to execute effective decisions. On November...

Insert Spaces Into a Character String: Quick Tip

In many SQL relational database you will have to use the RPAD function to insert spaces into a character string. That also works in Vertica. However, for a more robust solution, Vertica provides the built-in function SPACE which returns the specified number of blank spaces. Helpful Links: Have fun!

Find the Version of Vertica that Created a Database: Quick Tip

You can run the VERSION() function as one method of displaying the current version of Vertica. But what if you want to know the version of Vertica running when you created the current database? For that info you can query the VS_GLOBAL_SETTINGS table. Helpful Link: Have fun!

Rejected Data Table Row Number: Quick Tip

When running a COPY command, using the REJECTED DATA parameter with the AS TABLE clause saves rejected data into a table. The rejected data table includes an informative column called ROW_NUMBER where its value indicates the rejected row number from the input file. Be aware that when a COPY encounters an empty line while loading...

Reload Data from a Rejected Data Table: Quick Tip

When running a COPY command, using the REJECTED DATA parameter with the AS TABLE clause, will save rejected data into a table. If you realize there is a modification to the COPY command that will allow those rejected records to load successfully, you can re-run the updated COPY command against the rejected data in the...

Derive a Table Column’s Default Value from another Column: Quick Tip

Jim Knicely authored this tip. You can specify a table column's default value using a DEFAULT expression. To see how, check out this . When you set a default value, Vertica evaluates the DEFAULT expression and sets the column on load operations, if the operation omits a value for the column. In addition, that DEFAULT...

Default a Column’s Value: Quick Tip

Jim Knicely authored this tip You can specify a table column's default value using a DEFAULT expression. If the operation omits a value for the column, Vertica evaluates the DEFAULT expression and sets the column on load operations. Helpful Links: Have fun!