Despite the lack of ignore nulls syntax in postgres, we can mimic the required behavior by defining custom aggregates. Albeit being simple, it has several advantages.
Some time ago I have passed an exam 1Z0-071 Oracle Database SQL and received the certificate. I have stumbled across many problems, majority of them being of organizational nature. Here is a wrap up of how it looks like and what to expect. Note: I am not going to address the content of the exam, particularContinue reading “Oracle SQL certificate – is it worth it?”
Some time ago I had a pleasure to speak at Wrocław JUG about performance issues I have faced when working with persistence layer. These are not the most frequent ones, but rather the most tricky – not visible at the first sight and causing quite a lot of trouble in production.
0. The problem When I hear the term fuzzy searching, I think of high computation cost, but this is not always the case. In the great book Art of Computer Programming by D. Knuth, vol. 3, ch. 6: Searching we can read about the soundex algorithm. It was originally used to deal with misspelled EnglishContinue reading “Poor man’s fuzzy search”
Recently I have given a talk about top (in my opinion) performance issues we are challenged with when working with JPA (Hibernate) and SQL (Postgres, Oracle). The talk is in polish.
0. The problem Some time ago I’ve stumbled on this interesting question on stackoverflow (as stated in the title). I could not find any satisfactory answer at that time, so I came up with this solution. I think the problem is interesting enough to make it into a blog post. The following table shows theContinue reading “Calculating moving median in Postgres”