deterministic

When deterministic function is not

When you declare a function-based index, the function is deterministic, which means that calling it with same arguments will always return the same result. This is required because the indexed values, which are the result of the function, are stored in the index. But what happens if you declare a function deterministic when it is not?

I wanted to do this test after reading the following documents about Postgres HOT and WARM.

Keyword DETERMINISTIC is anything but…

According TheFreeDictionary.com, the word “deterministic” means…

deterministic
de·termin·istic adj. an inevitable consequence of antecedent sufficient causes

According to Wikipedia, the explanation of deterministic algorithm is…