Tag: autovacuum
Enabling and disabling autovacuum in PostgreSQL
UPDATED August 2023: Autovacuum has been part of PostgreSQL for a long time. But how does it really work? Can you simply turn it on and off? People keep asking us these questions about enabling and disabling autovacuum. PostgreSQL relies on MVCC to handle concurrency in a multiuser environment. The problem which arises with concurrent […]
zheap: Inspecting storage sizes
To dig a bit deeper into zheap and PostgreSQL storage technology in general I decided to provide some more empirical information about space consumption. As stated in my previous blog post about zheap is more efficient in terms of storage consumption. The reasons are: The tuple header is much smaller Alignment has been improved The […]
zheap: Reinvented PostgreSQL storage
In PostgreSQL table bloat has been a primary concern since the original MVCC model was conceived. Therefore we have decided to do a series of blog posts discussing this issue in more detail. What is table bloat in the first place? Table bloat means that a table and/or indexes are growing in size even if […]
“LOCK TABLE” can harm your database’s health
© Laurenz Albe 2019 Many people know that explicit table locks with LOCK TABLE are bad style and usually a consequence of bad design. The main reason is that they hamper concurrency and hence performance. Through a recent support case I learned that there are even worse effects of explicit table locks. Table locks […]
A beginners guide to PostgreSQL’s UPDATE and autovacuum
Looking at the type of PostgreSQL support requests, we have received recently, it is striking to see, how many of them are basically related to autovacuum and UPDATE in particular. Compared to other databases such as Oracle, PostgreSQL’s way of handling UPDATE and storage in general is quite different. Therefore people moving from Oracle to […]
Autovacuum wraparound protection in PostgreSQL
Autovacuum is maybe one of the most beloved, but also one of the most misunderstood features in the PostgreSQL world. Many questions reaching our PostgreSQL support team are somehow related to autovacuum or VACUUM in general. So maybe it makes sense to use this opportunity to shine some light on VACUUM and a thing called […]