@Override
public void analyze(Analyzer analyzer) throws AnalysisException, AuthorizationException {
super.analyze(analyzer);
Table t = getTargetTable();
String tableName = getDb() + "." + getTbl();
// Verify there are no conflicts with partition columns.
for (FieldSchema fs : t.getMetaStoreTable().getPartitionKeys()) {
if (fs.getName().toLowerCase().equals(colName.toLowerCase())) {
throw new AnalysisException("Cannot modify partition column: " + colName);
}
if (fs.getName().toLowerCase().equals(newColDef.getColName().toLowerCase())) {
throw new AnalysisException(
"Column name conflicts with existing partition column: " + newColDef.getColName());
}
}
// Verify the column being modified exists in the table
if (t.getColumn(colName) == null) {
throw new AnalysisException(
String.format("Column '%s' does not exist in table: %s", colName, tableName));
}
// Check that the new column def's name is valid.
newColDef.analyze();
// Verify that if the column name is being changed, the new name doesn't conflict
// with an existing column.
if (!colName.toLowerCase().equals(newColDef.getColName().toLowerCase())
&& t.getColumn(newColDef.getColName()) != null) {
throw new AnalysisException("Column already exists: " + newColDef.getColName());
}
}
/*
* Builds a TDescribeTableResult that contains the result of a DESCRIBE FORMATTED
* <table> command. For the formatted describe output the goal is to be exactly the
* same as what Hive (via HiveServer2) outputs, for compatibility reasons. To do this,
* Hive's MetadataFormatUtils class is used to build the results.
*/
private static TDescribeTableResult describeTableFormatted(Table table) {
TDescribeTableResult descResult = new TDescribeTableResult();
descResult.results = Lists.newArrayList();
org.apache.hadoop.hive.metastore.api.Table msTable = table.getMetaStoreTable().deepCopy();
// Fixup the metastore table so the output of DESCRIBE FORMATTED matches Hive's.
// This is to distinguish between empty comments and no comments (value is null).
for (FieldSchema fs : msTable.getSd().getCols())
fs.setComment(table.getColumn(fs.getName()).getComment());
for (FieldSchema fs : msTable.getPartitionKeys()) {
fs.setComment(table.getColumn(fs.getName()).getComment());
}
// To avoid initializing any of the SerDe classes in the metastore table Thrift
// struct, create the ql.metadata.Table object by calling the empty c'tor and
// then calling setTTable().
org.apache.hadoop.hive.ql.metadata.Table hiveTable =
new org.apache.hadoop.hive.ql.metadata.Table();
hiveTable.setTTable(msTable);
StringBuilder sb = new StringBuilder();
// First add all the columns (includes partition columns).
sb.append(
MetaDataFormatUtils.getAllColumnsInformation(
msTable.getSd().getCols(), msTable.getPartitionKeys()));
// Add the extended table metadata information.
sb.append(MetaDataFormatUtils.getTableInformation(hiveTable));
for (String line : sb.toString().split("\n")) {
// To match Hive's HiveServer2 output, split each line into multiple column
// values based on the field delimiter.
String[] columns = line.split(MetaDataFormatUtils.FIELD_DELIM);
TResultRow resultRow = new TResultRow();
for (int i = 0; i < NUM_DESC_FORMATTED_RESULT_COLS; ++i) {
TColumnValue colVal = new TColumnValue();
colVal.setString_val(null);
if (columns.length > i) {
// Add the column value.
colVal.setString_val(columns[i]);
}
resultRow.addToColVals(colVal);
}
descResult.results.add(resultRow);
}
return descResult;
}
