/**
* Invalidates the table in the catalog cache, potentially adding/removing the table from the
* cache based on whether it exists in the Hive Metastore. The invalidation logic is: - If the
* table exists in the metastore, add it to the catalog as an uninitialized IncompleteTable
* (replacing any existing entry). The table metadata will be loaded lazily, on the next access.
* If the parent database for this table does not yet exist in Impala's cache it will also be
* added. - If the table does not exist in the metastore, remove it from the catalog cache. - If
* we are unable to determine whether the table exists in the metastore (there was an exception
* thrown making the RPC), invalidate any existing Table by replacing it with an uninitialized
* IncompleteTable.
*
* <p>The parameter updatedObjects is a Pair that contains details on what catalog objects were
* modified as a result of the invalidateTable() call. The first item in the Pair is a Db which
* will only be set if a new database was added as a result of this call, otherwise it will be
* null. The second item in the Pair is the Table that was modified/added/removed. Returns a flag
* that indicates whether the items in updatedObjects were removed (returns true) or
* added/modified (return false). Only Tables should ever be removed.
*/
public boolean invalidateTable(TTableName tableName, Pair<Db, Table> updatedObjects) {
Preconditions.checkNotNull(updatedObjects);
updatedObjects.first = null;
updatedObjects.second = null;
LOG.debug(
String.format(
"Invalidating table metadata: %s.%s",
tableName.getDb_name(), tableName.getTable_name()));
String dbName = tableName.getDb_name();
String tblName = tableName.getTable_name();
// Stores whether the table exists in the metastore. Can have three states:
// 1) true - Table exists in metastore.
// 2) false - Table does not exist in metastore.
// 3) unknown (null) - There was exception thrown by the metastore client.
Boolean tableExistsInMetaStore;
MetaStoreClient msClient = getMetaStoreClient();
try {
tableExistsInMetaStore = msClient.getHiveClient().tableExists(dbName, tblName);
} catch (UnknownDBException e) {
// The parent database does not exist in the metastore. Treat this the same
// as if the table does not exist.
tableExistsInMetaStore = false;
} catch (TException e) {
LOG.error("Error executing tableExists() metastore call: " + tblName, e);
tableExistsInMetaStore = null;
} finally {
msClient.release();
}
if (tableExistsInMetaStore != null && !tableExistsInMetaStore) {
updatedObjects.second = removeTable(dbName, tblName);
return true;
} else {
Db db = getDb(dbName);
if ((db == null || !db.containsTable(tblName)) && tableExistsInMetaStore == null) {
// The table does not exist in our cache AND it is unknown whether the table
// exists in the metastore. Do nothing.
return false;
} else if (db == null && tableExistsInMetaStore) {
// The table exists in the metastore, but our cache does not contain the parent
// database. A new db will be added to the cache along with the new table.
db = new Db(dbName, this);
db.setCatalogVersion(incrementAndGetCatalogVersion());
addDb(db);
updatedObjects.first = db;
}
// Add a new uninitialized table to the table cache, effectively invalidating
// any existing entry. The metadata for the table will be loaded lazily, on the
// on the next access to the table.
Table newTable = IncompleteTable.createUninitializedTable(getNextTableId(), db, tblName);
newTable.setCatalogVersion(incrementAndGetCatalogVersion());
db.addTable(newTable);
if (loadInBackground_) {
tableLoadingMgr_.backgroundLoad(
new TTableName(dbName.toLowerCase(), tblName.toLowerCase()));
}
updatedObjects.second = newTable;
return false;
}
}
