Jesus Camacho Rodriguez created CALCITE-2943:
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Summary: Materialized view rewriting logic calls
getApplicableMaterializations each time the rule is triggered
Key: CALCITE-2943
URL: https://issues.apache.org/jira/browse/CALCITE-2943
Project: Calcite
Issue Type: Improvement
Components: core
Reporter: Jesus Camacho Rodriguez
Assignee: Jesus Camacho Rodriguez
Attachments: Screen Shot 2019-03-21 at 2.33.01 PM.png
{{RelOptMaterializations.getApplicableMaterializations}} is called each time
the rule is triggered.
{code:java}
...
// Obtain applicable (filtered) materializations
// TODO: Filtering of relevant materializations needs to be
// improved so we gather only materializations that might
// actually generate a valid rewriting.
final List<RelOptMaterialization> applicableMaterializations =
RelOptMaterializations.getApplicableMaterializations(node,
materializations);
...
{code}
When I implemented the rule, I assumed (incorrectly) that
{{getApplicableMaterializations}} was a lightweight call and hence would help
discarding materialized views extracted from the planner quickly. It turns out
that the method can quickly become the most time consuming part of the rule
execution; I assume the method was just supposed to be used once per query.
!Screen Shot 2019-03-21 at 2.33.01 PM.png!
Since the prefiltering that we do right now is rather simple and we already
extract the tables used by queries and materializations within the rule, we can
just skip the materialization over there.
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