ποΈ Gather statistics for CBO
This topic describes the basic concept of StarRocks cost-based optimizer (CBO) and how to collect statistics for the CBO to select an optimal query plan. StarRocks 2.4 introduces histograms to gather accurate data distribution statistics.
ποΈ Synchronous materialized view
This topic describes how to create, use, and manage a synchronous materialized view (Rollup).
ποΈ Asynchronous materialized views
5 items
ποΈ Colocate Join
For shuffle join and broadcast join, if the join condition is met, the data rows of the two joining tables are merged into a single node to complete the join. Neither of these two join methods can avoid latency or overhead caused by data network transmission between nodes.
ποΈ Use Lateral Join for column-to-row conversion
Column-to-row conversion is a common operation in ETL processing. Lateral is a special Join keyword that can associate a row with an internal subquery or table function. By using Lateral in conjunction with unnest(), you can expand one row into multiple rows. For more information, see unnest.
ποΈ Caching
2 items
ποΈ Computing the number of distinct values
2 items
ποΈ Sorted streaming aggregate
Common aggregation methods in database systems include hash aggregate and sort aggregate.
ποΈ Accelerate COUNT(DISTINCT) and Joins with AUTO INCREMENT and Global Dictionary
This topic describes how to accelerate COUNT(DISTINCT) calculation and Joins using AUTO INCREMENT columns and Global Dictionary.
ποΈ Accelerate Cardinality-Preserving Joins
This topic describes how to accelerate cardinality-preserving joins with table pruning. This feature is supported from v3.1 onwards.