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/**
* 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.hadoop.hive.ql.parse;
import java.io.IOException;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.hadoop.hive.conf.HiveConf;
import org.apache.hadoop.hive.metastore.api.FieldSchema;
import org.apache.hadoop.hive.ql.Context;
import org.apache.hadoop.hive.ql.ErrorMsg;
import org.apache.hadoop.hive.ql.hooks.Entity;
import org.apache.hadoop.hive.ql.hooks.ReadEntity;
import org.apache.hadoop.hive.ql.hooks.WriteEntity;
import org.apache.hadoop.hive.ql.io.AcidUtils;
import org.apache.hadoop.hive.ql.lib.Node;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.hadoop.hive.ql.metadata.InvalidTableException;
import org.apache.hadoop.hive.ql.metadata.Table;
import org.apache.hadoop.hive.ql.metadata.VirtualColumn;
import org.apache.hadoop.hive.ql.session.SessionState;
/**
* A subclass of the {@link org.apache.hadoop.hive.ql.parse.SemanticAnalyzer} that just handles
* update and delete statements. It works by rewriting the updates and deletes into insert
* statements (since they are actually inserts) and then doing some patch up to make them work as
* updates and deletes instead.
*/
public class UpdateDeleteSemanticAnalyzer extends SemanticAnalyzer {
boolean useSuper = false;
public UpdateDeleteSemanticAnalyzer(HiveConf conf) throws SemanticException {
super(conf);
}
@Override
public void analyzeInternal(ASTNode tree) throws SemanticException {
if (useSuper) {
super.analyzeInternal(tree);
} else {
if (!SessionState.get().getTxnMgr().supportsAcid()) {
throw new SemanticException(ErrorMsg.ACID_OP_ON_NONACID_TXNMGR.getMsg());
}
switch (tree.getToken().getType()) {
case HiveParser.TOK_DELETE_FROM:
analyzeDelete(tree);
return;
case HiveParser.TOK_UPDATE_TABLE:
analyzeUpdate(tree);
return;
default:
throw new RuntimeException("Asked to parse token " + tree.getName() + " in " +
"UpdateDeleteSemanticAnalyzer");
}
}
}
@Override
protected boolean updating() {
return ctx.getAcidOperation() == AcidUtils.Operation.UPDATE;
}
@Override
protected boolean deleting() {
return ctx.getAcidOperation() == AcidUtils.Operation.DELETE;
}
private void analyzeUpdate(ASTNode tree) throws SemanticException {
ctx.setAcidOperation(AcidUtils.Operation.UPDATE);
reparseAndSuperAnalyze(tree);
}
private void analyzeDelete(ASTNode tree) throws SemanticException {
ctx.setAcidOperation(AcidUtils.Operation.DELETE);
reparseAndSuperAnalyze(tree);
}
private void reparseAndSuperAnalyze(ASTNode tree) throws SemanticException {
List children = tree.getChildren();
// The first child should be the table we are deleting from
ASTNode tabName = (ASTNode)children.get(0);
assert tabName.getToken().getType() == HiveParser.TOK_TABNAME :
"Expected tablename as first child of " + operation() + " but found " + tabName.getName();
String[] tableName = getQualifiedTableName(tabName);
// Rewrite the delete or update into an insert. Crazy, but it works as deletes and update
// actually are inserts into the delta file in Hive. A delete
// DELETE FROM _tablename_ [WHERE ...]
// will be rewritten as
// INSERT INTO TABLE _tablename_ [PARTITION (_partcols_)] SELECT ROW__ID[,
// _partcols_] from _tablename_ SORT BY ROW__ID
// An update
// UPDATE _tablename_ SET x = _expr_ [WHERE...]
// will be rewritten as
// INSERT INTO TABLE _tablename_ [PARTITION (_partcols_)] SELECT _all_,
// _partcols_from _tablename_ SORT BY ROW__ID
// where _all_ is all the non-partition columns. The expressions from the set clause will be
// re-attached later.
// The where clause will also be re-attached later.
// The sort by clause is put in there so that records come out in the right order to enable
// merge on read.
StringBuilder rewrittenQueryStr = new StringBuilder();
Table mTable;
try {
mTable = db.getTable(tableName[0], tableName[1]);
} catch (InvalidTableException e) {
LOG.error("Failed to find table " + getDotName(tableName) + " got exception "
+ e.getMessage());
throw new SemanticException(ErrorMsg.INVALID_TABLE.getMsg(getDotName(tableName)), e);
} catch (HiveException e) {
LOG.error("Failed to find table " + getDotName(tableName) + " got exception "
+ e.getMessage());
throw new SemanticException(e.getMessage(), e);
}
List partCols = mTable.getPartCols();
rewrittenQueryStr.append("insert into table ");
rewrittenQueryStr.append(getDotName(tableName));
// If the table is partitioned we have to put the partition() clause in
if (partCols != null && partCols.size() > 0) {
rewrittenQueryStr.append(" partition (");
boolean first = true;
for (FieldSchema fschema : partCols) {
if (first) first = false;
else rewrittenQueryStr.append(", ");
rewrittenQueryStr.append(fschema.getName());
}
rewrittenQueryStr.append(")");
}
rewrittenQueryStr.append(" select ROW__ID");
Map setColExprs = null;
Map setCols = null;
Set setRCols = new HashSet();
if (updating()) {
// An update needs to select all of the columns, as we rewrite the entire row. Also,
// we need to figure out which columns we are going to replace. We won't write the set
// expressions in the rewritten query. We'll patch that up later.
// The set list from update should be the second child (index 1)
assert children.size() >= 2 : "Expected update token to have at least two children";
ASTNode setClause = (ASTNode)children.get(1);
assert setClause.getToken().getType() == HiveParser.TOK_SET_COLUMNS_CLAUSE :
"Expected second child of update token to be set token";
// Get the children of the set clause, each of which should be a column assignment
List assignments = setClause.getChildren();
setCols = new HashMap(assignments.size());
setColExprs = new HashMap(assignments.size());
for (Node a : assignments) {
ASTNode assignment = (ASTNode)a;
assert assignment.getToken().getType() == HiveParser.EQUAL :
"Expected set assignments to use equals operator but found " + assignment.getName();
ASTNode tableOrColTok = (ASTNode)assignment.getChildren().get(0);
assert tableOrColTok.getToken().getType() == HiveParser.TOK_TABLE_OR_COL :
"Expected left side of assignment to be table or column";
ASTNode colName = (ASTNode)tableOrColTok.getChildren().get(0);
assert colName.getToken().getType() == HiveParser.Identifier :
"Expected column name";
addSetRCols((ASTNode) assignment.getChildren().get(1), setRCols);
String columnName = colName.getText();
// Make sure this isn't one of the partitioning columns, that's not supported.
if (partCols != null) {
for (FieldSchema fschema : partCols) {
if (fschema.getName().equalsIgnoreCase(columnName)) {
throw new SemanticException(ErrorMsg.UPDATE_CANNOT_UPDATE_PART_VALUE.getMsg());
}
}
}
// This means that in UPDATE T SET x = _something_
// _something_ can be whatever is supported in SELECT _something_
setCols.put(columnName, (ASTNode)assignment.getChildren().get(1));
}
List nonPartCols = mTable.getCols();
for (int i = 0; i < nonPartCols.size(); i++) {
rewrittenQueryStr.append(',');
String name = nonPartCols.get(i).getName();
ASTNode setCol = setCols.get(name);
rewrittenQueryStr.append(name);
if (setCol != null) {
// This is one of the columns we're setting, record it's position so we can come back
// later and patch it up.
// Add one to the index because the select has the ROW__ID as the first column.
setColExprs.put(i + 1, setCol);
}
}
}
// If the table is partitioned, we need to select the partition columns as well.
if (partCols != null) {
for (FieldSchema fschema : partCols) {
rewrittenQueryStr.append(", ");
rewrittenQueryStr.append(fschema.getName());
}
}
rewrittenQueryStr.append(" from ");
rewrittenQueryStr.append(getDotName(tableName));
ASTNode where = null;
int whereIndex = deleting() ? 1 : 2;
if (children.size() > whereIndex) {
where = (ASTNode)children.get(whereIndex);
assert where.getToken().getType() == HiveParser.TOK_WHERE :
"Expected where clause, but found " + where.getName();
}
// Add a sort by clause so that the row ids come out in the correct order
rewrittenQueryStr.append(" sort by ROW__ID ");
// Parse the rewritten query string
Context rewrittenCtx;
try {
// Set dynamic partitioning to nonstrict so that queries do not need any partition
// references.
HiveConf.setVar(conf, HiveConf.ConfVars.DYNAMICPARTITIONINGMODE, "nonstrict");
rewrittenCtx = new Context(conf);
} catch (IOException e) {
throw new SemanticException(ErrorMsg.UPDATEDELETE_IO_ERROR.getMsg());
}
rewrittenCtx.setCmd(rewrittenQueryStr.toString());
rewrittenCtx.setAcidOperation(ctx.getAcidOperation());
ParseDriver pd = new ParseDriver();
ASTNode rewrittenTree;
try {
LOG.info("Going to reparse " + operation() + " as <" + rewrittenQueryStr.toString() + ">");
rewrittenTree = pd.parse(rewrittenQueryStr.toString(), rewrittenCtx);
rewrittenTree = ParseUtils.findRootNonNullToken(rewrittenTree);
} catch (ParseException e) {
throw new SemanticException(ErrorMsg.UPDATEDELETE_PARSE_ERROR.getMsg(), e);
}
ASTNode rewrittenInsert = (ASTNode)rewrittenTree.getChildren().get(1);
assert rewrittenInsert.getToken().getType() == HiveParser.TOK_INSERT :
"Expected TOK_INSERT as second child of TOK_QUERY but found " + rewrittenInsert.getName();
if (where != null) {
// The structure of the AST for the rewritten insert statement is:
// TOK_QUERY -> TOK_FROM
// \-> TOK_INSERT -> TOK_INSERT_INTO
// \-> TOK_SELECT
// \-> TOK_SORTBY
// The following adds the TOK_WHERE and its subtree from the original query as a child of
// TOK_INSERT, which is where it would have landed if it had been there originally in the
// string. We do it this way because it's easy then turning the original AST back into a
// string and reparsing it. We have to move the SORT_BY over one,
// so grab it and then push it to the second slot, and put the where in the first slot
ASTNode sortBy = (ASTNode)rewrittenInsert.getChildren().get(2);
assert sortBy.getToken().getType() == HiveParser.TOK_SORTBY :
"Expected TOK_SORTBY to be first child of TOK_SELECT, but found " + sortBy.getName();
rewrittenInsert.addChild(sortBy);
rewrittenInsert.setChild(2, where);
}
// Patch up the projection list for updates, putting back the original set expressions.
if (updating() && setColExprs != null) {
// Walk through the projection list and replace the column names with the
// expressions from the original update. Under the TOK_SELECT (see above) the structure
// looks like:
// TOK_SELECT -> TOK_SELEXPR -> expr
// \-> TOK_SELEXPR -> expr ...
ASTNode rewrittenSelect = (ASTNode)rewrittenInsert.getChildren().get(1);
assert rewrittenSelect.getToken().getType() == HiveParser.TOK_SELECT :
"Expected TOK_SELECT as second child of TOK_INSERT but found " +
rewrittenSelect.getName();
for (Map.Entry entry : setColExprs.entrySet()) {
ASTNode selExpr = (ASTNode)rewrittenSelect.getChildren().get(entry.getKey());
assert selExpr.getToken().getType() == HiveParser.TOK_SELEXPR :
"Expected child of TOK_SELECT to be TOK_SELEXPR but was " + selExpr.getName();
// Now, change it's child
selExpr.setChild(0, entry.getValue());
}
}
try {
useSuper = true;
super.analyze(rewrittenTree, rewrittenCtx);
} finally {
useSuper = false;
}
// Walk through all our inputs and set them to note that this read is part of an update or a
// delete.
for (ReadEntity input : inputs) {
input.setUpdateOrDelete(true);
}
if (inputIsPartitioned(inputs)) {
// In order to avoid locking the entire write table we need to replace the single WriteEntity
// with a WriteEntity for each partition
outputs.clear();
for (ReadEntity input : inputs) {
if (input.getTyp() == Entity.Type.PARTITION) {
WriteEntity.WriteType writeType = deleting() ? WriteEntity.WriteType.DELETE :
WriteEntity.WriteType.UPDATE;
outputs.add(new WriteEntity(input.getPartition(), writeType));
}
}
} else {
// We still need to patch up the WriteEntities as they will have an insert type. Change
// them to the appropriate type for our operation.
for (WriteEntity output : outputs) {
output.setWriteType(deleting() ? WriteEntity.WriteType.DELETE :
WriteEntity.WriteType.UPDATE);
}
}
// For updates, we need to set the column access info so that it contains information on
// the columns we are updating.
if (updating()) {
ColumnAccessInfo cai = new ColumnAccessInfo();
for (String colName : setCols.keySet()) {
cai.add(Table.getCompleteName(mTable.getDbName(), mTable.getTableName()), colName);
}
setUpdateColumnAccessInfo(cai);
// Add the setRCols to the input list
for (String colName : setRCols) {
if(columnAccessInfo != null) {//assuming this means we are not doing Auth
columnAccessInfo.add(Table.getCompleteName(mTable.getDbName(), mTable.getTableName()),
colName);
}
}
}
// We need to weed ROW__ID out of the input column info, as it doesn't make any sense to
// require the user to have authorization on that column.
if (columnAccessInfo != null) {
columnAccessInfo.stripVirtualColumn(VirtualColumn.ROWID);
}
}
private String operation() {
if (updating()) return "update";
else if (deleting()) return "delete";
else throw new IllegalStateException("UpdateDeleteSemanticAnalyzer neither updating nor " +
"deleting, operation not known.");
}
private boolean inputIsPartitioned(Set inputs) {
// We cannot simply look at the first entry, as in the case where the input is partitioned
// there will be a table entry as well. So look for at least one partition entry.
for (ReadEntity re : inputs) {
if (re.getTyp() == Entity.Type.PARTITION) {
return true;
}
}
return false;
}
// This method find any columns on the right side of a set statement (thus rcols) and puts them
// in a set so we can add them to the list of input cols to check.
private void addSetRCols(ASTNode node, Set setRCols) {
// See if this node is a TOK_TABLE_OR_COL. If so, find the value and put it in the list. If
// not, recurse on any children
if (node.getToken().getType() == HiveParser.TOK_TABLE_OR_COL) {
ASTNode colName = (ASTNode)node.getChildren().get(0);
assert colName.getToken().getType() == HiveParser.Identifier :
"Expected column name";
setRCols.add(colName.getText());
} else if (node.getChildren() != null) {
for (Node n : node.getChildren()) {
addSetRCols((ASTNode)n, setRCols);
}
}
}
}
