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HeatWave User Guide  /  ...  /  Using Views

2.3.10 Using Views

HeatWave supports querying views. The table or tables upon which a view is created must be loaded in HeatWave. Queries executed on views are subject to the same offload prerequisites and limitations as queries executed on tables.

In the following example, a view is created on the orders table, described in Section 2.6, “Table Load and Query Example”. The example assumes the orders table is loaded in HeatWave.

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mysql> CREATE VIEW v1 AS SELECT O_ORDERPRIORITY, O_ORDERDATE FROM orders;

To determine if a query executed on a view can be offloaded to HeatWave for execution, use EXPLAIN. If offload is supported, the Extra column of EXPLAIN output shows Using secondary engine RAPID, as in the following example:

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mysql> EXPLAIN SELECT O_ORDERPRIORITY, COUNT(*) AS ORDER_COUNT FROM v1 WHERE O_ORDERDATE >= DATE '1994-03-01' GROUP BY O_ORDERPRIORITY ORDER BY O_ORDERPRIORITY; *************************** 1. row *************************** id: 1 select_type: SIMPLE table: ORDERS partitions: NULL type: ALL possible_keys: NULL key: NULL key_len: NULL ref: NULL rows: 1488248 filtered: 33.32999801635742 Extra: Using where; Using temporary; Using filesort; Using secondary engine RAPID