-
Notifications
You must be signed in to change notification settings - Fork 189
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
[Coral-Trino] Cast char fields, if necessary, to varchar type in the …
…set operation (#442) In case of dealing with Hive views which make use of set operation (e.g. UNION) ensure that the `char` fields from the inner SELECT statements have the same type as the output field types of the set operation. Due to wrong coercion between `varchar` and `char` in Trino, as described in trinodb/trino#9031 , a work-around needs to be applied in case of translating Hive views which contain a UNION dealing with char and varchar types. The work-around consists in the explicit cast of the field having char type towards varchar type corresponding of the set operation output type.
- Loading branch information
1 parent
a886a95
commit 4bb38a1
Showing
6 changed files
with
273 additions
and
2 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
180 changes: 180 additions & 0 deletions
180
...rc/main/java/com/linkedin/coral/trino/rel2trino/transformers/UnionSqlCallTransformer.java
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,180 @@ | ||
| /** | ||
| * Copyright 2023 LinkedIn Corporation. All rights reserved. | ||
| * Licensed under the BSD-2 Clause license. | ||
| * See LICENSE in the project root for license information. | ||
| */ | ||
| package com.linkedin.coral.trino.rel2trino.transformers; | ||
|
|
||
| import java.util.ArrayList; | ||
| import java.util.List; | ||
| import java.util.Optional; | ||
|
|
||
| import org.apache.calcite.rel.type.RelDataType; | ||
| import org.apache.calcite.sql.SqlBasicTypeNameSpec; | ||
| import org.apache.calcite.sql.SqlCall; | ||
| import org.apache.calcite.sql.SqlCallBinding; | ||
| import org.apache.calcite.sql.SqlDataTypeSpec; | ||
| import org.apache.calcite.sql.SqlIdentifier; | ||
| import org.apache.calcite.sql.SqlKind; | ||
| import org.apache.calcite.sql.SqlNode; | ||
| import org.apache.calcite.sql.SqlNodeList; | ||
| import org.apache.calcite.sql.SqlSelect; | ||
| import org.apache.calcite.sql.SqlTypeNameSpec; | ||
| import org.apache.calcite.sql.fun.SqlCastFunction; | ||
| import org.apache.calcite.sql.fun.SqlStdOperatorTable; | ||
| import org.apache.calcite.sql.parser.SqlParserPos; | ||
| import org.apache.calcite.sql.type.SqlTypeName; | ||
| import org.apache.calcite.sql.validate.SqlValidator; | ||
| import org.apache.calcite.sql.validate.SqlValidatorScope; | ||
|
|
||
| import com.linkedin.coral.common.transformers.SqlCallTransformer; | ||
| import com.linkedin.coral.common.utils.TypeDerivationUtil; | ||
|
|
||
| import static org.apache.calcite.rel.rel2sql.SqlImplementor.POS; | ||
| import static org.apache.calcite.sql.parser.SqlParserPos.ZERO; | ||
|
|
||
|
|
||
| /** | ||
| * This transformer class is used to adapt expressions in | ||
| * set statements (e.g.: `UNION`, `INTERSECT`, `MINUS`) | ||
| * in case that the branches of the set statement contain fields in | ||
| * char family which have different types. | ||
| * The `char` fields which are differing from the expected `varchar` output | ||
| * of the set statement will be adapted through an explicit `CAST` to the `varchar` type. | ||
| * | ||
| * @see <a href="https://github.com/trinodb/trino/issues/9031">Change char/varchar coercion in Trino</a> | ||
| */ | ||
| public class UnionSqlCallTransformer extends SqlCallTransformer { | ||
|
|
||
| public UnionSqlCallTransformer(TypeDerivationUtil typeDerivationUtil) { | ||
| super(typeDerivationUtil); | ||
| } | ||
|
|
||
| @Override | ||
| protected boolean condition(SqlCall sqlCall) { | ||
| return sqlCall.getOperator().kind == SqlKind.UNION || sqlCall.getOperator().kind == SqlKind.INTERSECT | ||
| || sqlCall.getOperator().kind == SqlKind.MINUS; | ||
| } | ||
|
|
||
| @Override | ||
| protected SqlCall transform(SqlCall sqlCall) { | ||
| List<SqlNode> operandsList = sqlCall.getOperandList(); | ||
| if (sqlCall.getOperandList().isEmpty()) { | ||
| return sqlCall; | ||
| } | ||
| Integer selectListSize = null; | ||
| // Ensure all the operand are SELECT nodes and they have the same number of expressions projected | ||
| for (SqlNode operand : operandsList) { | ||
| if (operand.getKind() == SqlKind.SELECT && ((SqlSelect) operand).getSelectList() != null) { | ||
| SqlSelect select = (SqlSelect) operand; | ||
| List<SqlNode> selectList = select.getSelectList().getList(); | ||
| if (selectListSize == null) { | ||
| selectListSize = selectList.size(); | ||
| } else if (selectListSize != selectList.size()) { | ||
| return sqlCall; | ||
| } | ||
| } else { | ||
| return sqlCall; | ||
| } | ||
| } | ||
|
|
||
| List<Optional<RelDataType>> leastRestrictiveSelectItemTypes = new ArrayList<>(selectListSize); | ||
| for (int i = 0; i < selectListSize; i++) { | ||
| List<RelDataType> selectItemTypes = new ArrayList<>(); | ||
| boolean selectItemTypesDerived = true; | ||
| for (SqlNode operand : operandsList) { | ||
| SqlSelect select = (SqlSelect) operand; | ||
| List<SqlNode> selectList = select.getSelectList().getList(); | ||
| SqlNode selectItem = selectList.get(i); | ||
| if (selectItem.getKind() == SqlKind.IDENTIFIER && ((SqlIdentifier) selectItem).isStar()) { | ||
| // The type derivation of * on the SqlNode layer is not supported now. | ||
| return sqlCall; | ||
| } | ||
|
|
||
| try { | ||
| selectItemTypes.add(deriveRelDatatype(selectItem)); | ||
| } catch (RuntimeException e) { | ||
| // The type derivation may fail for complex expressions | ||
| selectItemTypesDerived = false; | ||
| break; | ||
| } | ||
| } | ||
|
|
||
| Optional<RelDataType> leastRestrictiveSelectItemType = | ||
| selectItemTypesDerived ? Optional.ofNullable(leastRestrictive(selectItemTypes)) : Optional.empty(); | ||
| leastRestrictiveSelectItemTypes.add(leastRestrictiveSelectItemType); | ||
| } | ||
|
|
||
| boolean operandsUpdated = false; | ||
| for (SqlNode operand : operandsList) { | ||
| SqlSelect select = (SqlSelect) operand; | ||
| List<SqlNode> selectList = select.getSelectList().getList(); | ||
| List<SqlNode> rewrittenSelectList = null; | ||
| for (int i = 0; i < selectList.size(); i++) { | ||
| SqlNode selectItem = selectList.get(i); | ||
| if (!leastRestrictiveSelectItemTypes.get(i).isPresent()) { | ||
| // Couldn't determine the type for all the expressions corresponding to the selection index | ||
| if (rewrittenSelectList != null) { | ||
| rewrittenSelectList.add(selectItem); | ||
| } | ||
| continue; | ||
| } | ||
| RelDataType leastRestrictiveSelectItemType = leastRestrictiveSelectItemTypes.get(i).get(); | ||
| RelDataType selectItemType = deriveRelDatatype(selectItem); | ||
| if (selectItemType.getSqlTypeName() == SqlTypeName.CHAR | ||
| && leastRestrictiveSelectItemType.getSqlTypeName() == SqlTypeName.VARCHAR) { | ||
| // Work-around for the Trino limitation in dealing UNION statements between `char` and `varchar`. | ||
| // See https://github.com/trinodb/trino/issues/9031 | ||
| SqlNode rewrittenSelectItem = castNode(selectItem, leastRestrictiveSelectItemType); | ||
| if (rewrittenSelectList == null) { | ||
| rewrittenSelectList = new ArrayList<>(selectListSize); | ||
| rewrittenSelectList.addAll(selectList.subList(0, i)); | ||
| operandsUpdated = true; | ||
| } | ||
| rewrittenSelectList.add(rewrittenSelectItem); | ||
| } else if (rewrittenSelectList != null) { | ||
| rewrittenSelectList.add(selectItem); | ||
| } | ||
| } | ||
|
|
||
| if (rewrittenSelectList != null) { | ||
| select.setSelectList(new SqlNodeList(rewrittenSelectList, SqlParserPos.ZERO)); | ||
| } | ||
| } | ||
|
|
||
| if (operandsUpdated) { | ||
| return sqlCall.getOperator().createCall(POS, operandsList); | ||
| } | ||
|
|
||
| return sqlCall; | ||
| } | ||
|
|
||
| private SqlNode castNode(SqlNode node, RelDataType type) { | ||
| if (node.getKind() == SqlKind.AS) { | ||
| SqlNode expression = ((SqlCall) node).getOperandList().get(0); | ||
| SqlIdentifier identifier = (SqlIdentifier) ((SqlCall) node).getOperandList().get(1); | ||
| return SqlStdOperatorTable.AS.createCall(POS, new SqlCastFunction() { | ||
| @Override | ||
| public RelDataType deriveType(SqlValidator validator, SqlValidatorScope scope, SqlCall call) { | ||
| SqlCallBinding opBinding = new SqlCallBinding(validator, scope, call); | ||
| return inferReturnType(opBinding); | ||
| } | ||
| }.createCall(ZERO, expression, getSqlDataTypeSpec(type)), identifier); | ||
| } else { | ||
| // If there's no existing alias, just do the cast | ||
| return new SqlCastFunction() { | ||
| @Override | ||
| public RelDataType deriveType(SqlValidator validator, SqlValidatorScope scope, SqlCall call) { | ||
| SqlCallBinding opBinding = new SqlCallBinding(validator, scope, call); | ||
| return inferReturnType(opBinding); | ||
| } | ||
| }.createCall(ZERO, node, getSqlDataTypeSpec(type)); | ||
| } | ||
| } | ||
|
|
||
| private static SqlDataTypeSpec getSqlDataTypeSpec(RelDataType relDataType) { | ||
| final SqlTypeNameSpec typeNameSpec = new SqlBasicTypeNameSpec(relDataType.getSqlTypeName(), | ||
| relDataType.getPrecision(), relDataType.getScale(), null, ZERO); | ||
| return new SqlDataTypeSpec(typeNameSpec, ZERO); | ||
| } | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters