SCRAM Is Here to Stay
SCRAM was first introduced in Postgres 10 and has been enhanced in most major release since. In summary: Postgres 10 Added SCRAM-SHA-256 password encryption support for client/server communication and...
View ArticleAll About ALL
SQL is a powerful declarative language — you tell it what you want, and the optimizer determines the fastest way to produce the desired result. Of course, the language is not perfect. I already blogged...
View ArticleCombining Queries into CTEs
My common table expression (CTE) talk shows how CTEs can be used to combine individual queries into a single CTE query. This email thread explores the downsides of such combinations, and when combining...
View ArticleLATERAL Usage
LATERAL is a powerful SQL feature that allows virtual tables to be created in FROM clauses that reference real or virtual tables that appeared previously in the same FROM clause. Here is a simple...
View ArticleTransaction Block Isolation Levels
When a single query is run outside of a transaction block, it is clear how transaction visibility should behave — only transactions committed before the query started should be visible. Changes made by...
View ArticleIs SQL Good?
The Postgres mailing lists are full of practical discussions, but two years ago there was a 77-email thread titled "The tragedy of SQL" that questioned the utility of the SQL query language; t is worth...
View ArticleIndexing TIMESTAMPs
TIMESTAMPs are very precise and flexible in Postgres, but sometimes users want to do index lookups of TIMESTAMP values with less precision, i.e., by date. To illustrate this, let's create a sample...
View ArticleMultiply Time
Reading the title, you might think it is about multiplying INTERVAL values. Well, no, it is about something much larger. If you are an application developer, database administrator, or Postgres...
View ArticleIn Praise of PostgreSQL
At the risk of causing undue pride in the community, I want to share a blog post in praise of Postgres. This early paragraph captures his sentiments: After 25 years of persistence, and a better logo...
View ArticleSpecialized CPU Instructions
C compilers do a great job of converting C to assembly language (optionally) and then to primitive CPU instructions. However, some CPU instructions are too specialized or too complex to map to the C...
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