- Elasticsearch – Relevance Tuning That Is Not Guesswork
A relevance complaint is never settled by opinion. What BM25 actually computes, reading the _explain output that shows the arithmetic, what a field boost is worth and why ^2 shows up as 4.4, the multi_match types and a real bug one of them caused — “san francisco loft” returning nothing — fuzziness, and folding a rating into a text score with function_score without letting it take over.
- Elasticsearch – bool, Filters and the Filter Cache
How real queries are assembled. The four bool clauses — must, filter, should, must_not — and the distinction that decides both correctness and speed: filter clauses do not score and are cached, must clauses score and never can be. Then term versus terms when a filter panel has two boxes ticked, ranges, exists, and why a filter on a text field quietly matches the wrong things.
- Elasticsearch – The Search API and Query DSL
The read side, in the order you need it. The anatomy of a response, match versus term and the single most common beginner bug hiding in that difference, multi_match across fields, _source filtering, pagination and the 10,000-result wall that from + size hits, track_total_hits, and highlighting — including the setting that stops a highlighted fragment from being an XSS hole.
- MySQL Trigger
A MySQL trigger is a stored program that is invoked automatically in response to an event such as INSERT, UPDATE, or DELETE to a particualar table. There are two types of triggers Row-level trigger: a row-level trigger is activated for each row that is inserted, updated, or deleted. Statement-level…
- Linux SSH
SSH stands for “Secure Shell”. It is a protocol used to securely connect to a remote server. ssh is secure in the sense that it transfers the data in encrypted form between the host and the client. It transfers inputs from the client to the host and relays back the output. ssh runs at TCP/IP […]