Google Cloud Platform for Architects

Solving hot-spotting

Recall that while talking about the row key in the four-dimensional data model, we mentioned that data is stored in sorted lexicographic order of the row key. This is similar to Cloud Spanner. Data is sharded based on those key values, so that data that has the same key value will be grouped together. This implies that performance will be really poor if all of the reads and writes end up being concentrated in some particular shards or some ranges of the key values. A classic example is if sequential key values are used. There are some fairly typical techniques to solve hot-spotting, one of which is field promotion.

Here, the idea is that you use a structured key that is arranged in a reverse URL order, like a Java package ...