PostgreSQL: Detecting periods of activity in a timeseries
I have already written about timeseries and PostgreSQL in the past. However, recently I stumbled across an interesting problem, which caught my attention: Sometimes you might want to find “periods” of activity in a timseries. For example: When was a user active? Or when did we receive data? This blog post tries to give you […]
CREATE VIEW vs. ALTER TABLE in PostgreSQL
In PostgreSQL, a view is a virtual table based on an SQL statement. It is an abstraction layer, which allows to access the result of a more complex SQL fast an easily. The fields in a view are fields from one or more real tables in the database. The question many people now ask if: […]
Mapping Oracle datatypes to PostgreSQL
For those of you out there working with PostgreSQL in a professional way, migrating from Oracle to PostgreSQL might be one of the most beloved tasks available. One of the first things most people will notice, however, is that those data types available in Oracle might not be quite the same in PostgreSQL. This blog […]
PostgreSQL: Sharing data across function calls
Recently I did some PostgreSQL consulting in the Berlin area (Germany) when I stumbled over an interesting request: How can data be shared across function calls in PostgreSQL? I recalled some one of the other features of PostgreSQL (15+ years old or so) to solve the issue. Here is how it works. Stored procedures in […]
Tech preview: PostgreSQL 11 – CREATE PROCEDURE
Many people have asked for this feature for years and PostgreSQL 11 will finally have it. I am of course talking about CREATE PROCEDURE. Traditionally PostgreSQL has provided all the means to write functions (which were often simply called “stored procedures”). However, in a function you cannot really run transactions – all you can do […]
ora_migrator: Moving from Oracle to PostgreSQL even faster
As some of you might know Cybertec has been doing PostgreSQL consulting, tuning and 24×7 support for many years now. However, one should not only see what is going on in the PostgreSQL market. It also makes sense to look left and right to figure out what the rest of the world is up to […]
idle_in_transaction_session_timeout: Terminating idle transactions in PostgreSQL
When running PostgreSQL on a production system, it might happen that you are facing table bloat. As you might know PostgreSQL has to copy a row on UPDATE to ensure that concurrent transactions can still see the data. At some point VACUUM can clean out dead rows but if transactions are too long, this cleanup […]
Advanced SQL: Why first_value and last_value are no bugs
SQL is a must, if you want to be a Data Analyst or a Data Scientist. However, one in a while people are wondering, why a result is the way it is. While on the road in Berlin (Germany) the other day I have found a fairly interesting scenario, which is pretty counterintuitive to most […]
PostgreSQL: Speeding up analytics and windowing functions
As a professional PostgreSQL support company we see a lot of SQL performance stuff, which is often worth sharing. One of those noteworthy things, which might be interesting to you, the reader, happened this week when I was out on a business trip to Berlin, Germany. This (excellent) customer was making extensive use of windowing […]
What PostgreSQL Full-Text-Search has to do with VACUUM
What does PostgreSQL Full-Text-Search have to do with VACUUM? Many readers might actually be surprised that there might be a relevant connection worth talking about at all. However, those two topics are more closely related than people might actually think. The reason is buried deep inside the code and many people might not be aware […]
COPY in PostgreSQL: Moving data between servers
The COPY command in PostgreSQL is a simple means to copy data between a file and a table. COPY can either copy the content of a table to or from a table. Traditionally data was copied between PostgreSQL and a file. However, recently a pretty cool feature was added to PostgreSQL: It is now possible […]
PostgreSQL performance: How the optimizer handles views
“How does the PostgreSQL optimizer handle views?” or “Are views good or bad?” I assume that every database consultant and every SQL performance expert has heard this kind of question already in the past. Most likely this does not only hold true for PostgreSQL experts but is also true for Oracle, DB2 and MS SQL […]