© Laurenz Albe 2022 A while ago, I wrote about the performance impact of query parameter data types. Recently I encountered a similar problem with UNION ALL that baffled me for a while, so I’d like to share it with you. UNION ALL to implement polymorphism Different entities can have something in common. For example, […]

While the term faceting may sound foreign to you, you almost certainly have run into it in your adventures online. It is those helpful little boxes that turn up when browsing in web shops or searching in catalogs, telling how to further narrow down the search results, (for example, by color) and how many items […]

© Laurenz Albe 2022 Sometimes a PostgreSQL query takes forever. Usually, it is easy to interrupt (cancel) such a statement, but sometimes it can turn into a problem, and a query cannot be canceled. This article discusses what might be the cause. I’ll also show you a trick how to solve the problem (not for […]

Spot a missing PostgreSQL index Missing indexes are a key ingredient if you are looking for a perfect recipe to ruin performance in the most efficient way possible. 🙂  However, if you want to ensure that your database performs well and if you are generally not in favor of user complaints – better watch out […]

© Laurenz Albe 2022 Table partitioning is one of the best-liked features out of the more recent PostgreSQL developments. However, there is no support for automatic partition creation yet. This article shows what you can do to remedy that. Use cases for automatic partition creation There are essentially two use cases: Create partitions triggered by […]

Over the years, many of our PostgreSQL clients have asked whether it makes sense to create indexes before – or after – importing data. Does it make sense to disable indexes when bulk loading data, or is it better to keep them enabled? This is an important question for people involved in data warehousing and […]

© Laurenz Albe 2021 PostgreSQL v12 brought more efficient storage for indexes, and v13 improved that even more by adding deduplication of index entries. But Peter Geoghegan wasn’t finished! PostgreSQL v14 added “bottom-up” index entry deletion, which targets reducing unnecessary page splits, index bloat and fragmentation of heavily updated indexes. Why do we get index […]

© Laurenz Albe 2021 EXPLAIN ANALYZE is the key to optimizing SQL statements in PostgreSQL. This article does not attempt to explain everything there is to it. Rather, I want to give you a brief introduction, explain what to look for and show you some helpful tools to visualize the output. How to call EXPLAIN […]

UPDATED March 2023: In this post, we’ll focus our attention on PostgreSQL performance and detecting slow queries. Performance tuning does not only mean adjusting postgresql.conf properly, or making sure that your kernel parameters are properly tuned. Performance tuning also implies that you need to first find performance bottlenecks, isolate slow queries and understand what the […]

PostgreSQL offers a nice BLOB interface which is widely used. However, recently we came across problems faced by various customers, and it makes sense to reflect a bit and figure out how PostgreSQL handles BLOBs – and especially BLOB cleanup. Using the PostgreSQL BLOB interface In PostgreSQL, you can use various means to store binary […]

© Laurenz Albe 2020 UPDATED blog article on 09.01.2023 HOT updates are not a new feature. They were introduced by commit 282d2a03dd in 2007 and first appeared in PostgreSQL 8.3. But since HOT is not covered by the PostgreSQL documentation (although there is a README.HOT in the source tree), it is not as widely known […]

LIKE and ILIKE are two fundamental SQL features. People use those things all over the place in their application and therefore it makes sense to approach the topic from a performance point of view. What can PostgreSQL do to speed up those operations and what can be done in general to first understand the problem […]