}
public void alterTable(RawStore msdb, Warehouse wh, String dbname,
String name, Table newt) throws InvalidOperationException, MetaException {
if (newt == null) {
throw new InvalidOperationException("New table is invalid: " + newt);
}
if (!MetaStoreUtils.validateName(newt.getTableName())
|| !MetaStoreUtils.validateColNames(newt.getSd().getCols())) {
throw new InvalidOperationException(newt.getTableName()
+ " is not a valid object name");
}
Path srcPath = null;
FileSystem srcFs = null;
Path destPath = null;
FileSystem destFs = null;
boolean success = false;
String oldTblLoc = null;
String newTblLoc = null;
boolean moveData = false;
boolean rename = false;
Table oldt = null;
try {
msdb.openTransaction();
name = name.toLowerCase();
dbname = dbname.toLowerCase();
// check if table with the new name already exists
if (!newt.getTableName().equalsIgnoreCase(name)
|| !newt.getDbName().equalsIgnoreCase(dbname)) {
if (msdb.getTable(newt.getDbName(), newt.getTableName()) != null) {
throw new InvalidOperationException("new table " + newt.getDbName()
+ "." + newt.getTableName() + " already exists");
}
rename = true;
}
// get old table
oldt = msdb.getTable(dbname, name);
if (oldt == null) {
throw new InvalidOperationException("table " + newt.getDbName() + "."
+ newt.getTableName() + " doesn't exist");
}
// check that partition keys have not changed
if (oldt.getPartitionKeys().size() != newt.getPartitionKeys().size()
|| !oldt.getPartitionKeys().containsAll(newt.getPartitionKeys())) {
throw new InvalidOperationException(
"partition keys can not be changed.");
}
// if this alter is a rename, and user didn't change the
// default location (or new location is empty), and table is
// not an external table, that means user is asking metastore
// to move data to new location corresponding to the new name
if (rename
&& (oldt.getSd().getLocation().compareTo(newt.getSd().getLocation()) == 0
|| StringUtils.isEmpty(newt.getSd().getLocation()))
&& !MetaStoreUtils.isExternalTable(oldt)) {
// that means user is asking metastore to move data to new location
// corresponding to the new name
// get new location
newTblLoc = wh.getDefaultTablePath(newt.getDbName(), newt.getTableName()).toString();
newt.getSd().setLocation(newTblLoc);
oldTblLoc = oldt.getSd().getLocation();
moveData = true;
// check that destination does not exist otherwise we will be
// overwriting data
srcPath = new Path(oldTblLoc);
srcFs = wh.getFs(srcPath);
destPath = new Path(newTblLoc);
destFs = wh.getFs(destPath);
// check that src and dest are on the same file system
if (srcFs != destFs) {
throw new InvalidOperationException("table new location " + destPath
+ " is on a different file system than the old location "
+ srcPath + ". This operation is not supported");
}
try {
srcFs.exists(srcPath); // check that src exists and also checks
// permissions necessary
if (destFs.exists(destPath)) {
throw new InvalidOperationException("New location for this table "
+ newt.getDbName() + "." + newt.getTableName()
+ " already exists : " + destPath);
}
} catch (IOException e) {
Warehouse.closeFs(srcFs);
Warehouse.closeFs(destFs);
throw new InvalidOperationException("Unable to access new location "
+ destPath + " for table " + newt.getDbName() + "."
+ newt.getTableName());
}
// also the location field in partition
List<Partition> parts = msdb.getPartitions(dbname, name, 0);
for (Partition part : parts) {
String oldPartLoc = part.getSd().getLocation();
Path oldPartLocPath = new Path(oldPartLoc);
String oldTblLocPath = new Path(oldTblLoc).toUri().getPath();
String newTblLocPath = new Path(newTblLoc).toUri().getPath();
if (oldPartLoc.contains(oldTblLocPath)) {
Path newPartLocPath = null;
URI oldUri = oldPartLocPath.toUri();
String newPath = oldUri.getPath().replace(oldTblLocPath,
newTblLocPath);
newPartLocPath = new Path(oldUri.getScheme(),
oldUri.getAuthority(),
newPath);
part.getSd().setLocation(newPartLocPath.toString());
msdb.alterPartition(dbname, name, part);
}
}
}
// now finally call alter table
msdb.alterTable(dbname, name, newt);
// commit the changes
success = msdb.commitTransaction();
} catch (InvalidObjectException e) {
LOG.debug(e);
throw new InvalidOperationException(
"Unable to change partition or table."
+ " Check metastore logs for detailed stack." + e.getMessage());
} finally {
if (!success) {
msdb.rollbackTransaction();
}
if (success && moveData) {
// change the file name in hdfs
// check that src exists otherwise there is no need to copy the data
try {
if (srcFs.exists(srcPath)) {
// rename the src to destination
srcFs.rename(srcPath, destPath);
}
} catch (IOException e) {
boolean revertMetaDataTransaction = false;
try {
msdb.openTransaction();
msdb.alterTable(dbname, newt.getTableName(), oldt);
revertMetaDataTransaction = msdb.commitTransaction();
} catch (Exception e1) {
LOG.error("Reverting metadata opeation failed During HDFS operation failed", e1);
if (!revertMetaDataTransaction) {
msdb.rollbackTransaction();
}
}
throw new InvalidOperationException("Unable to access old location "
+ srcPath + " for table " + dbname + "." + name);
}
}
}