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https://issues.apache.org/jira/browse/CALCITE-3531?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17008227#comment-17008227
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Danny Chen commented on CALCITE-3531:
-------------------------------------
Thanks [~amaliujia] for looking into this again, in standard SQL, if we do not
specify the time zone explicitly, the default time zone of current session is
always chosen, this does not illustrate that the value should also be evaluated
as the same in one session.
Hive and PostgreSQL can have such behaviors because they are either batch or
SQL-engines, i'm hesitant to suggest a new function for per-row times
evaluation, the CURRENT_TIMESTAMP name is straight-forward, what other name
should we choose ?
Calcite does not implement CURRENT_TIMESTAMP as bindable, see
{code:java}
/** SQL {@code CURRENT_TIMESTAMP} function. */
@NonDeterministic
public static long currentTimestamp(DataContext root) {
// Cast required for JDK 1.6.
return (Long) DataContext.Variable.CURRENT_TIMESTAMP.get(root);
}
{code}
> AggregateProjectPullUpConstantsRule should not remove deterministic function
> group key if the function is dynamic
> -----------------------------------------------------------------------------------------------------------------
>
> Key: CALCITE-3531
> URL: https://issues.apache.org/jira/browse/CALCITE-3531
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Affects Versions: 1.21.0
> Reporter: Danny Chen
> Assignee: Danny Chen
> Priority: Major
> Labels: pull-request-available
> Fix For: 1.22.0
>
> Time Spent: 2h 10m
> Remaining Estimate: 0h
>
> Now AggregateProjectPullUpConstantsRule simplify the query:
> {code:sql}
> select hiredate
> from sales.emp
> where sal is null and hiredate = current_timestamp
> group by sal, hiredate
> having count(*) > 3
> {code}
> from plan:
> {code:xml}
> LogicalProject(HIREDATE=[$1])
> LogicalFilter(condition=[>($2, 3)])
> LogicalAggregate(group=[{0, 1}], agg#0=[COUNT()])
> LogicalProject(SAL=[$5], HIREDATE=[$4])
> LogicalFilter(condition=[AND(IS NULL($5), =($4, CURRENT_TIMESTAMP))])
> LogicalTableScan(table=[[CATALOG, SALES, EMP]])
> {code}
> to plan:
> {code:xml}
> LogicalProject(HIREDATE=[$1])
> LogicalFilter(condition=[>($2, 3)])
> LogicalProject(SAL=[$0], HIREDATE=[CURRENT_TIMESTAMP], $f2=[$1])
> LogicalAggregate(group=[{0}], agg#0=[COUNT()])
> LogicalProject(SAL=[$5], HIREDATE=[$4])
> LogicalFilter(condition=[AND(IS NULL($5), =($4,
> CURRENT_TIMESTAMP))])
> LogicalTableScan(table=[[CATALOG, SALES, EMP]])
> {code}
> which is unsafe, because for stream sql, we need to group data by dateTime,
> also the result is wrong if a batch job runs across days.
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