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https://issues.apache.org/jira/browse/CALCITE-5251?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17597590#comment-17597590
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Ruben Q L commented on CALCITE-5251:
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bq. BTW, more and more RelNodes implement {{Hintable}} we may need to re-think
the design about whether we should abstract out the Hintable as base clazz for
all the RelNodes for purpose of hints propagation or something.
FYI I created some time ago CALCITE-5188, which could be used for this purpose.
> Support SQL hint for Snapshot
> -----------------------------
>
> Key: CALCITE-5251
> URL: https://issues.apache.org/jira/browse/CALCITE-5251
> Project: Calcite
> Issue Type: New Feature
> Reporter: lincoln lee
> Priority: Major
> Labels: pull-request-available
> Time Spent: 10m
> Remaining Estimate: 0h
>
> 1. Current `snapshot` does not support hint yet and this blocks hint
> propagation to the underlying temporal table(As query hints, all operators
> included in the query may have the need to propagate hint, current hint
> propagation depends on whether the node is hintable).
> 2. When do a [temporal join in
> Flink|https://nightlies.apache.org/flink/flink-docs-master/docs/dev/table/sql/queries/joins/#event-time-temporal-join],
> the snapshot maybe optimized in some cases (to reserve less versions of the
> managed versioned-table), e.g.,
> {code}
> select /*+ snapshot('max-version'='1') */ stream *
> from orders o join products_temporal for system_time as of orders.proctime as
> p
> on o.productid = p.productid
> {code}
> currently, the following node tree has no hint on `LogicalSnapshot`
> {code}
> LogicalDelta
> LogicalProject(PROCTIME=[$0], PRODUCTID=[$1], ORDERID=[$2],
> PRODUCTID0=[$3], NAME=[$4], SUPPLIERID=[$5], SYS_START=[$6], SYS_END=[$7])
> LogicalFilter(condition=[=($1, $3)])
> LogicalCorrelate(correlation=[$cor0], joinType=[inner],
> requiredColumns=[\{0}])
> LogicalTableScan(table=[[CATALOG, SALES, ORDERS]])
> LogicalSnapshot(period=[$cor0.PROCTIME])
> LogicalTableScan(table=[[CATALOG, SALES, PRODUCTS_TEMPORAL]])
> {code}
> If snapshot could be extended to support hint, it would make this
> optimization possible.
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