PrestoDB Questions & Answers

Reasons for Presto queries running slow, diagnosis, tuning, things to check and possible solutions: How many workers do you have in your cluster? If your PrestoDB cluster has many (>50) … Continue reading Presto queries running slow?

Let’s say we have some JSON that looks like this: In this instance our json contains key value pairs. How can we decode that using PrestoDB SQL to extract only … Continue reading Extract keys in a nested JSON array object

There are numerous ways of generating intervals using PrestoDB SQL for different data types. Dates Date intervals can be generated for a given date range using a combination of the … Continue reading Generate Interval from Variable

In reality there will be some occasions when you need to use a quote character in your data, in your query, or in result sets, but you want the SQL … Continue reading How To Escape a Single Quote

SQL has a number of functions for dealing with null values, and everyone has their favorite. The complicating factor is that not all SQL engines support all the functions, and … Continue reading Check if null and return default (NVL analog)

Many databases automatically convert between CHAR or VARCHAR and other types like DATE and TIMESTAMP as a convenience feature.  Using constants in a query are also often auto-converted.  Take these … Continue reading Static date and timestamp in where clause

A common question is “where are Presto’s bootstrap logs?”  These are logs that indicate what is happening to the cluster on startup. The Presto server generates them, and the content … Continue reading Where can I find the Presto Server Bootstrap logs?

There are several ways to monitor Presto.  Let’s look at some options. 1. Presto Console Presto provides a web interface for monitoring and managing queries. The web interface is accessible … Continue reading Where can I find different Presto metrics for monitoring?

Presto needs a data directory for storing logs, etc. and it is recommended this is created in a data directory outside of the installation directory (which allows it to be … Continue reading Where do I find Presto logs?

PrestoDB supports ANSI SQL and includes support for several SQL dialects, including MySQL dialect, making it easy to group and aggregate data in a variety of ways. However not ALL … Continue reading Presto equivalent of mysql group_concat

How to get the Presto CLI Tool The Presto CLI provides a terminal-based interactive shell for running queries. The CLI is a self-executing JAR file, which means it acts like … Continue reading How to get the Presto CLI Tool | Presto-CLI Download | Ahana

How To Convert Date String to Presto Date Format PrestoDB supports ANSI SQL and includes support for several SQL dialects, so it’s straightforward to convert a date string to date … Continue reading Convert Date String to Date Format in Presto | Presto Date Format

The main branch: PrestoDB source code Presto is an open source project that is developed in the open on the public Github repository: https://github.com/prestodb/presto. The prestodb repo is the original, … Continue reading Where to Find Presto Source Code, and How to Work With it