public MutationState dropColumn(DropColumnStatement statement) throws SQLException {
connection.rollback();
boolean wasAutoCommit = connection.getAutoCommit();
try {
connection.setAutoCommit(false);
TableName tableNameNode = statement.getTableName();
String schemaName = tableNameNode.getSchemaName();
String tableName = tableNameNode.getTableName();
PTable table = getLatestTable(schemaName, tableName); // TODO: Do in resolver?
boolean retried = false;
while (true) {
final ColumnResolver resolver = FromCompiler.getResolver(statement, connection);
ColumnRef columnRef = null;
try {
columnRef = resolver.resolveColumn((ColumnParseNode) statement.getColumnRef());
} catch (ColumnNotFoundException e) {
if (statement.ifExists()) {
return new MutationState(0, connection);
}
throw e;
}
TableRef tableRef = columnRef.getTableRef();
PColumn columnToDrop = columnRef.getColumn();
if (SchemaUtil.isPKColumn(columnToDrop)) {
throw new SQLExceptionInfo.Builder(SQLExceptionCode.CANNOT_DROP_PK)
.setColumnName(columnToDrop.getName().getString())
.build()
.buildException();
}
int columnCount = table.getColumns().size() - 1;
String familyName = null;
List<String> binds = Lists.newArrayListWithExpectedSize(4);
StringBuilder buf =
new StringBuilder(
"DELETE FROM " + TYPE_SCHEMA + ".\"" + TYPE_TABLE + "\" WHERE " + TABLE_SCHEM_NAME);
if (schemaName == null || schemaName.length() == 0) {
buf.append(" IS NULL AND ");
} else {
buf.append(" = ? AND ");
binds.add(schemaName);
}
buf.append(TABLE_NAME_NAME + " = ? AND " + COLUMN_NAME + " = ? AND " + TABLE_CAT_NAME);
binds.add(tableName);
binds.add(columnToDrop.getName().getString());
if (columnToDrop.getFamilyName() == null) {
buf.append(" IS NULL");
} else {
buf.append(" = ?");
binds.add(familyName = columnToDrop.getFamilyName().getString());
}
PreparedStatement colDelete = connection.prepareStatement(buf.toString());
for (int i = 0; i < binds.size(); i++) {
colDelete.setString(i + 1, binds.get(i));
}
colDelete.execute();
PreparedStatement colUpdate = connection.prepareStatement(UPDATE_COLUMN_POSITION);
colUpdate.setString(1, schemaName);
colUpdate.setString(2, tableName);
for (int i = columnToDrop.getPosition() + 1; i < table.getColumns().size(); i++) {
PColumn column = table.getColumns().get(i);
colUpdate.setString(3, column.getName().getString());
colUpdate.setString(
4, column.getFamilyName() == null ? null : column.getFamilyName().getString());
colUpdate.setInt(5, i);
colUpdate.execute();
}
final long seqNum = table.getSequenceNumber() + 1;
PreparedStatement tableUpsert = connection.prepareStatement(MUTATE_TABLE);
tableUpsert.setString(1, schemaName);
tableUpsert.setString(2, tableName);
tableUpsert.setString(3, table.getType().getSerializedValue());
tableUpsert.setLong(4, seqNum);
tableUpsert.setInt(5, columnCount);
tableUpsert.execute();
final List<Mutation> tableMetaData = connection.getMutationState().toMutations();
connection.rollback();
// If we're dropping the last KV colum, we have to pass an indication along to the
// dropColumn call
// to populate a new empty KV column
byte[] emptyCF = null;
if (table.getType() != PTableType.VIEW
&& !SchemaUtil.isPKColumn(columnToDrop)
&& table.getColumnFamilies().get(0).getName().equals(columnToDrop.getFamilyName())
&& table.getColumnFamilies().get(0).getColumns().size() == 1) {
emptyCF =
SchemaUtil.getEmptyColumnFamily(
table.getColumnFamilies().subList(1, table.getColumnFamilies().size()));
}
MetaDataMutationResult result =
connection
.getQueryServices()
.dropColumn(
tableMetaData,
emptyCF != null
&& Bytes.compareTo(emptyCF, QueryConstants.EMPTY_COLUMN_BYTES) == 0
? emptyCF
: null);
try {
MutationCode code = processMutationResult(schemaName, tableName, result);
if (code == MutationCode.COLUMN_NOT_FOUND) {
connection.addTable(schemaName, result.getTable());
if (!statement.ifExists()) {
throw new ColumnNotFoundException(
schemaName, tableName, familyName, columnToDrop.getName().getString());
}
return new MutationState(0, connection);
}
connection.removeColumn(
schemaName,
tableName,
familyName,
columnToDrop.getName().getString(),
seqNum,
result.getMutationTime());
// If we have a VIEW, then only delete the metadata, and leave the table data alone
if (table.getType() != PTableType.VIEW) {
connection.setAutoCommit(true);
Long scn = connection.getSCN();
// Delete everything in the column. You'll still be able to do queries at earlier
// timestamps
long ts = (scn == null ? result.getMutationTime() : scn);
MutationPlan plan =
new PostDDLCompiler(connection)
.compile(tableRef, emptyCF, Collections.singletonList(columnToDrop), ts);
return connection.getQueryServices().updateData(plan);
}
return new MutationState(0, connection);
} catch (ConcurrentTableMutationException e) {
if (retried) {
throw e;
}
table = connection.getPMetaData().getSchema(schemaName).getTable(tableName);
retried = true;
}
}
} finally {
connection.setAutoCommit(wasAutoCommit);
}
}
