Jesus Camacho Rodriguez created CALCITE-2179:
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Summary: General improvements for materialized view rewriting rule
Key: CALCITE-2179
URL: https://issues.apache.org/jira/browse/CALCITE-2179
Project: Calcite
Issue Type: Improvement
Components: core
Reporter: Jesus Camacho Rodriguez
Assignee: Jesus Camacho Rodriguez
Fix For: 1.16.0
This issue is for extending {{AbstractMaterializedViewRule}} rule:
- Support for rolling up date nodes. For instance, rewrite in the following
case:
{code}
Materialization:
select "empid", floor(cast('1997-01-20' as timestamp) to month), count(*) + 1
as c, sum("empid") as s
from "emps" group by "empid", floor(cast('1997-01-20' as timestamp) to month);
Query:
select floor(cast('1997-01-20' as timestamp) to year), sum("empid") as s
from "emps" group by floor(cast('1997-01-20' as timestamp) to year);
{code}
- Add flag to enable/disable fast bail out for joins. By default it is true,
and thus, we were only creating the rewriting in the minimal subtree of plan
operators. For instance:
{code}
View: (A JOIN B) JOIN C
Query: (((A JOIN B) JOIN D) JOIN C) JOIN E
{code}
We produce it at:
{code}
((A JOIN B) JOIN D) JOIN C
{code}
But not at:
{code}
(((A JOIN B) JOIN D) JOIN C) JOIN E
{code}
This is important when the rule is used with the Volcano planner together with
other rules, e.g. join reordering, as it prevents that the search space grows
unnecessarily. However, if we use the rewriting rule in isolation, fast bail
out can lead to missing rewriting opportunities (e.g. for bushy join trees).
- Possibility to provide a HepProgram to optimize query branch in union
rewritings. Note that when we produce a partial rewriting with a Union, the
branch that will execute the (partial) query can be fully rewritten so we can
add the compensation predicate. (We cannot do the same for views because the
expression might not be computable if the needed subexpressions are not
available in the view output). If we use Volcano with a determined set of
rules, this might not be needed, hence providing this program is optional.
- Multiple small fixes discovered while testing.
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