Java tutorial
/** * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.drill.exec.planner.sql.handlers; import com.google.common.collect.Lists; import com.google.common.collect.Sets; import org.apache.calcite.rel.type.RelDataTypeField; import org.apache.calcite.rex.RexBuilder; import org.apache.calcite.rex.RexInputRef; import org.apache.calcite.rex.RexLiteral; import org.apache.calcite.rex.RexNode; import org.apache.calcite.schema.Table; import org.apache.calcite.sql.SqlNodeList; import org.apache.calcite.sql.SqlWriter; import org.apache.calcite.sql.TypedSqlNode; import org.apache.calcite.sql.fun.SqlStdOperatorTable; import org.apache.calcite.tools.Planner; import org.apache.calcite.tools.RelConversionException; import org.apache.drill.common.exceptions.DrillException; import org.apache.drill.common.exceptions.DrillRuntimeException; import org.apache.drill.common.exceptions.UserException; import org.apache.drill.exec.planner.StarColumnHelper; import org.apache.drill.exec.planner.common.DrillRelOptUtil; import org.apache.drill.exec.planner.sql.DirectPlan; import org.apache.drill.exec.planner.types.DrillFixedRelDataTypeImpl; import org.apache.drill.exec.store.AbstractSchema; import org.apache.calcite.tools.ValidationException; import org.apache.calcite.rel.RelNode; import org.apache.calcite.plan.RelOptUtil; import org.apache.calcite.rel.type.RelDataType; import org.apache.calcite.sql.SqlNode; import org.apache.drill.exec.store.ischema.Records; import java.util.AbstractList; import java.util.HashSet; import java.util.List; public class SqlHandlerUtil { private static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(SqlHandlerUtil.class); /** * Resolve final RelNode of the new table (or view) for given table field list and new table definition. * * @param isNewTableView Is the new table created a view? This doesn't affect the functionality, but it helps format * better error messages. * @param tableFieldNames List of fields specified in new table/view field list. These are the fields given just after * new table name. * Ex. CREATE TABLE newTblName(col1, medianOfCol2, avgOfCol3) AS * SELECT col1, median(col2), avg(col3) FROM sourcetbl GROUP BY col1; * @throws ValidationException If table's fields list and field list specified in table definition are not valid. * @throws RelConversionException If failed to convert the table definition into a RelNode. */ public static RelNode resolveNewTableRel(boolean isNewTableView, List<String> tableFieldNames, RelDataType validatedRowtype, RelNode queryRelNode) throws ValidationException, RelConversionException { // TypedSqlNode validatedSqlNodeWithType = planner.validateAndGetType(newTableQueryDef); // Get the row type of view definition query. // Reason for getting the row type from validated SqlNode than RelNode is because SqlNode -> RelNode involves // renaming duplicate fields which is not desired when creating a view or table. // For ex: SELECT region_id, region_id FROM cp.`region.json` LIMIT 1 returns // +------------+------------+ // | region_id | region_id0 | // +------------+------------+ // | 0 | 0 | // +------------+------------+ // which is not desired when creating new views or tables. // final RelDataType queryRowType = validatedRowtype; if (tableFieldNames.size() > 0) { // Field count should match. if (tableFieldNames.size() != validatedRowtype.getFieldCount()) { final String tblType = isNewTableView ? "view" : "table"; throw UserException.validationError() .message("%s's field list and the %s's query field list have different counts.", tblType, tblType) .build(logger); } // CTAS's query field list shouldn't have "*" when table's field list is specified. for (String field : validatedRowtype.getFieldNames()) { if (field.equals("*")) { final String tblType = isNewTableView ? "view" : "table"; throw UserException.validationError().message( "%s's query field list has a '*', which is invalid when %s's field list is specified.", tblType, tblType).build(logger); } } // validate the given field names to make sure there are no duplicates ensureNoDuplicateColumnNames(tableFieldNames); // CTAS statement has table field list (ex. below), add a project rel to rename the query fields. // Ex. CREATE TABLE tblname(col1, medianOfCol2, avgOfCol3) AS // SELECT col1, median(col2), avg(col3) FROM sourcetbl GROUP BY col1 ; // Similary for CREATE VIEW. return DrillRelOptUtil.createRename(queryRelNode, tableFieldNames); } // As the column names of the view are derived from SELECT query, make sure the query has no duplicate column names ensureNoDuplicateColumnNames(validatedRowtype.getFieldNames()); return queryRelNode; } private static void ensureNoDuplicateColumnNames(List<String> fieldNames) throws ValidationException { final HashSet<String> fieldHashSet = Sets.newHashSetWithExpectedSize(fieldNames.size()); for (String field : fieldNames) { if (fieldHashSet.contains(field.toLowerCase())) { throw new ValidationException(String.format("Duplicate column name [%s]", field)); } fieldHashSet.add(field.toLowerCase()); } } /** * Resolve the partition columns specified in "PARTITION BY" clause of CTAS statement. * * A partition column is resolved, either (1) the same column appear in the select list of CTAS * or (2) CTAS has a * in select list. * * In the second case, a PROJECT with ITEM expression would be created and returned. * Throw validation error if a partition column is not resolved correctly. * * @param input : the RelNode represents the select statement in CTAS. * @param partitionColumns : the list of partition columns. * @return : 1) the original RelNode input, if all partition columns are in select list of CTAS * 2) a New Project, if a partition column is resolved to * column in select list * 3) validation error, if partition column is not resolved. */ public static RelNode qualifyPartitionCol(RelNode input, List<String> partitionColumns) { final RelDataType inputRowType = input.getRowType(); final List<RexNode> colRefStarExprs = Lists.newArrayList(); final List<String> colRefStarNames = Lists.newArrayList(); final RexBuilder builder = input.getCluster().getRexBuilder(); final int originalFieldSize = inputRowType.getFieldCount(); for (final String col : partitionColumns) { final RelDataTypeField field = inputRowType.getField(col, false, false); if (field == null) { throw UserException.validationError() .message("Partition column %s is not in the SELECT list of CTAS!", col).build(logger); } else { if (field.getName().startsWith(StarColumnHelper.STAR_COLUMN)) { colRefStarNames.add(col); final List<RexNode> operands = Lists.newArrayList(); operands.add(new RexInputRef(field.getIndex(), field.getType())); operands.add(builder.makeLiteral(col)); final RexNode item = builder.makeCall(SqlStdOperatorTable.ITEM, operands); colRefStarExprs.add(item); } } } if (colRefStarExprs.isEmpty()) { return input; } else { final List<String> names = new AbstractList<String>() { @Override public String get(int index) { if (index < originalFieldSize) { return inputRowType.getFieldNames().get(index); } else { return colRefStarNames.get(index - originalFieldSize); } } @Override public int size() { return originalFieldSize + colRefStarExprs.size(); } }; final List<RexNode> refs = new AbstractList<RexNode>() { public int size() { return originalFieldSize + colRefStarExprs.size(); } public RexNode get(int index) { if (index < originalFieldSize) { return RexInputRef.of(index, inputRowType.getFieldList()); } else { return colRefStarExprs.get(index - originalFieldSize); } } }; return RelOptUtil.createProject(input, refs, names, false); } } public static Table getTableFromSchema(AbstractSchema drillSchema, String tblName) { try { return drillSchema.getTable(tblName); } catch (Exception e) { // TODO: Move to better exception types. throw new DrillRuntimeException( String.format( "Failure while trying to check if a table or view with given name [%s] already exists " + "in schema [%s]: %s", tblName, drillSchema.getFullSchemaName(), e.getMessage()), e); } } public static void unparseSqlNodeList(SqlWriter writer, int leftPrec, int rightPrec, SqlNodeList fieldList) { writer.keyword("("); fieldList.get(0).unparse(writer, leftPrec, rightPrec); for (int i = 1; i < fieldList.size(); i++) { writer.keyword(","); fieldList.get(i).unparse(writer, leftPrec, rightPrec); } writer.keyword(")"); } }