Product area
Query History
Query History and Query Profile: reading the plan, spotting bottlenecks, optimizing queries on warehouses.
Concepts
- 1Reading the query profileQuery History lists every statement run on a SQL warehouse, with duration, user, and status. Opening one and clicking See query profile shows a query profile: a directed graph of the operators the engine actually executed — scans, joins, aggregations…Intermediate
- 2Query tagsA query tag is a key-value pair attached to SQL work. You set it, the queries that follow carry it, and it appears next to them in query history and in system.query.history.Intermediate Preview
- 3Query caching layersBetween your statement and the data files there are five independent caches. Four of them hold query results; one holds data files. They have different owners, different lifetimes, and one of them can hand you a stale answer.Intermediate
- 4Query performance insightsWhen a statement finishes, Databricks reads its own execution and returns performance insights: named findings, each with a recommendation you can act on, ranked by their estimated effect on total task duration. Some tell you what to change. Others, labelled…Intermediate
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