[Coral-Trino] Support CROSS JOIN for Correlated Inner Queries #493
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ljfgem
reviewed
Mar 1, 2024
| * @param unnestSqlCall unnest sqlCall | ||
| * @return true if the sqlCall is correlated to the outer query | ||
| */ | ||
| private static boolean isUnnestSqlCallCorrelated(SqlCall unnestSqlCall) { |
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Can this method be removed as it just calls isSqlCallCorrelation?
KevinGe00
reviewed
Mar 4, 2024
| return true; | ||
| private static boolean isSqlCallCorrelation(SqlCall sqlCall) { | ||
| for (SqlNode operand : sqlCall.getOperandList()) { | ||
| if (operand instanceof SqlIdentifier) { |
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How do we know for sure that any identifier operand of an unnest operator references a column from the base tables? Could it be a reference to a non-base table column?
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all tables referenced can be seen as base tables.
| || (unnestOperand instanceof SqlCall | ||
| && ((SqlCall) unnestOperand).getOperator().getName().equalsIgnoreCase("transform")) | ||
| || (unnestOperand instanceof SqlCall | ||
| && ((SqlCall) unnestOperand).getOperator().getName().equalsIgnoreCase("if"))) { |
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Is the "if" case here lost because we now recurse using isSqlCallCorrelation into the operands of an "if" ?
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"if" is another SqlOperator. So now we recursively examine the operands of If operator, if and when encountered.
KevinGe00
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to KevinGe00/coral
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Mar 13, 2024
…in#493) * [Coral-Trino] Enhancement to support CROSS JOIN for correlated inner query * remove isUnnestSqlCallCorrelated
This was referenced Mar 14, 2024
KevinGe00
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Mar 15, 2024
…500) * [Coral-Trino] Enhancement to support CROSS JOIN for correlated inner query * remove isUnnestSqlCallCorrelated Co-authored-by: Aastha Agrrawal <[email protected]>
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Prior to this PR, given an input hive SQL query like:
Coral generated an incorrect Trino SQL:
Since the unnest argument is correlated to the outer query, the expected Trino translation is:
The pre-existing logic in Coral was hard coded to recognize correlation based on specific patterns in the unnest argument. This PR generalizes that logic by recursively checking the unnest argument(s) to make that decision.
What changes are proposed in this pull request, and why are they necessary?
How was this patch tested?
./gradlew build
existing UTs pass + added a new UT + i-tested against production views.
tested for the previously failing production views