There are some aspects of
VACUUM whose reason to exist is complex to explain, and occasionally they have negative behavior. Let's look more deeply at those and find some solutions.
PostgreSQL performs regular sweeps to clean out old transaction identifiers, which is known as "freezing". It does this to defer transaction wraparound, which is discussed in more detail in the next recipe.
There are two routes that a row can take in PostgreSQL: a row version dies and needs to be removed by
VACUUM, or a row version gets old enough and needs to be frozen, which is also performed by the
Why do we care? Say, we load a table with 100 million rows, and everything is fine. When those rows ...