Databricks · Databricks Data Analyst Associate
Photon, query history, and caching
Databricks Data Analyst Associate · Lesson 11 of 18 · 1:21:20
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In this lesson
Prepare for the Databricks Certified Data Analyst Associate exam. In this lesson: the Photon engine, query history and the query history system table, the query profile and its insights (spills, exploding joins), the result cache and the disk cache, and measuring a query without the cache. Includes three original practice questions.
Preview the topics
- A new analyst asks what to change in the SQL code, so that the queries on Cobbleway’s SQL warehouse use Photon. What is the right answer?
- A query got slow. In its profile, one join operator returns forty times more rows than it receives, and the insights flag it. What is the most likely cause?
- The analyst tunes a query and runs it again to compare timings, but every run after the first returns in a few milliseconds, and nothing can be measured. What should the analyst do?