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Setting Session Authorization to Troubleshoot

Sruthi Anumula, Senior Database Support Engineer
September 29, 2023

There are possible scenarios in which a dbadmin would want to run queries as another user to troubleshoot or test. You can use SET SESSION AUTHORIZATION to impersonate another user and run queries. Let's understand this with an example. Here we create a user named test, resource pool named userpool, and make this a default...

UNNEST vs EXPLODE Functions

Sruthi Anumula, Senior Database Support Engineer
September 19, 2023

Vertica provides two functions, UNNEST and EXPLODE to expand arrays into one or more rows. These functions offer the same functionality with subtle differences in syntax and output. Let's understand with a simple example. We have 3 array columns in the table. Let us expand 1 array column for a particular order key. Explode provides...

Checklist for Inconsistent Execution Time of Same Query in Eon Mode

Sruthi Anumula, Senior Database Support Engineer
September 6, 2023

In Eon Mode, when a query is executed and if the ROS containers associated to the tables in the query are not present in depot, it will fetch results from the communal storage bucket. In the next immediate run, the query should provide results to the user from the files present in the depot. However,...
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Using Fallthrough Authentication

Sruthi Anumula, Senior Database Support Engineer
July 21, 2023

Prior to Vertica 12.0.x, if a user failed to log in with a some authentication method, they could not attempt to log in again with some other method. For example, if a user used failed to log in with hash authentication, they could not attempt to log in with LDAP in the same connection attempt....

Creating Iceberg External Tables in Vertica

Sruthi Anumula, Senior Database Support Engineer
June 1, 2023

From Vertica 12.0.4 onwards, we support creating external tables with parquet files in Apache Iceberg Table format. Iceberg is a high-performance table format which uses advanced filtering techniques and provides better performance by avoiding file listing. The striking feature of the external Iceberg tables is that there is no need to specify columns when defining...
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Default Custom User Resource Pool

Sruthi Anumula, Senior Database Support Engineer
May 9, 2023

In Vertica versions 12.0.4 and later, you can set a default user resource pool for all users instead of defaulting users to a general pool, using the DefaultResourcePoolForUsers configuration parameter. How to set it? As a dbadmin user, create a user resource pool. The pool name can be used to configure the DefaultResourcePoolForUsers option. In...

Load Balancing on Elastic Kubernetes Clusters

Sruthi Anumula, Senior Database Support Engineer
March 7, 2023

Your long-running sessions could fail after you deployed Vertica on Elastic Kubernetes Cluster (EKS) with Load Balancer as the service type. When the load balancer type is not specified in yaml, by default, EKS generates a classic load balancer with a default connection idle timeout of 60 seconds. The aws-load-balancer-connection-idle-timeout can be set up to...
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Restrict Modifying Table Rows (UPDATE/DELETE) Irrespective of User Privileges

Sruthi Anumula, Senior Database Support Engineer
February 14, 2023

Do you have a table with critical information such as SIEM events or credit card transactions? Do you want to be able to block user access to UPDATE/DELETE rows in those tables? From version 12.0.0, you can do this by setting the tables as IMMUTABLE. This means you can only insert data and not modify...
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High Availability for a Vertica in Eon Mode Database with Read-Only Mode

Sruthi Anumula, Senior Database Support Engineer
January 9, 2023

When Vertica is deployed in Eon Mode, there are two major requirements for high availability: maintaining quorum and shard coverage. If either of them is lost, the whole cluster goes down. Before going into details, let us understand what quorum and shard coverage mean. Quorum: In Eon Mode, more than half of the primary nodes...

How to Quickly Install Vertica on Large Clusters

Sruthi Anumula, Senior Database Support Engineer
December 19, 2022

Vertica 12.0.2 introduces a new feature that allows you to install Vertica in parallel on all hosts rather than one at a time as in earlier releases. This reduces the installation time in large clusters. To use this feature, run the --parallel-no-prompts flag with the install_vertica command. This flag can be used only when passwordless...
SQL Query Optimization

Improving COUNT DISTINCT Performance with Approximate Functions

Bryan Herger, Vertica Big Data Solution Architect at Micro Focus
November 16, 2022

A common analytic use case is to find the number of distinct items in a data set. Vertica performs well at solving COUNT DISTINCT in a few ways. Since Vertica stores all data in columns, it is possible to optimize for COUNT DISTINCT by building a projection that is tuned for this use case. Vertica...

How to run Vertica CE in Windows 10 using Docker

Alexandr Skorobogatov
September 14, 2021

Sometimes we want to test a new version of Vertica. In the past, the best way to do that was to use a Vertica Community Edition (CE) virtual machine. But starting with Vertica version 10.1, there is an easier way to achieve this. There is an official Docker image for the latest Vertica CE version...