Limit path

The LIMIT path restricts the number of result rows based on the LIMIT clause in the query. Using the LIMIT clause in queries with thousands of rows might increase query performance.

The optimizer pushes the LIMIT operation as far down as possible in queries. A single LIMIT clause in the query can generate multiple Output Only plan annotations.

 => EXPLAIN SELECT COUNT(DISTINCT annual_income) FROM customer_dimension LIMIT 10;
Access Path:
 +-SELECT  LIMIT 10 [Cost: 161, Rows: 10] (PATH ID: 0)
 |  Output Only: 10 tuples
 | +---> GROUPBY NOTHING [Cost: 161, Rows: 1] (PATH ID: 1)
 | |      Aggregates: count(DISTINCT customer_dimension.annual_income)
 | |      Output Only: 10 tuples
 | | +---> GROUPBY HASH (SORT OUTPUT) [Cost: 158, Rows: 10K] (PATH ID: 2)
 | | |      Group By: customer_dimension.annual_income
 | | | +---> STORAGE ACCESS for customer_dimension [Cost: 132, Rows: 50K] (PATH ID: 3)
 | | | |      Projection: public.customer_dimension_DBD_1_rep_vmartdb_design_vmartdb_design_node0001
 | | | |      Materialize: customer_dimension.annual_income