I like that the diagram expands the JSONB structure. Does it still show the nested JSONB fields when the table has relationships or joins with other tables?
10 karma · joined May 23, 2025
If a system is working fine, the expense and risk of moving may end up being far greater than any optimization efforts on the existing database. This is also why I believe profiling tools, explain plans, and indexes are all useful; there are plenty of cases where MongoDB is sufficient but still needs optimization...
That's also why I decided to concentrate on the entire workflow rather than on the index itself in the article: Find the slow query -> Analyze Explain -> Analyze the ratio between scanned and returned documents -> Create an index -> Test the same query again...
In this particular case, a compound index was selected based on filters and a sort clause. I completely agree that using index intersections in a real workload could be quite dangerous, especially if MongoDB chooses to use another index instead.
The `$addToSet` example is also very valid; however, for me, that is more like a schema problem than a regular indexing problem in a read query. Still, the array could become extremely big regardless of the presence of indexes, and it might require a dedicated note in the article.