/**
* Prioritizes the loading of the given list TCatalogObjects. Currently only support loading
* Table/View metadata since Db and Function metadata is not loaded lazily.
*/
public void prioritizeLoad(List<TCatalogObject> objectDescs) {
for (TCatalogObject catalogObject : objectDescs) {
Preconditions.checkState(catalogObject.isSetTable());
TTable table = catalogObject.getTable();
tableLoadingMgr_.prioritizeLoad(
new TTableName(table.getDb_name().toLowerCase(), table.getTbl_name().toLowerCase()));
}
}
/**
* Reloads a table's metadata, reusing any existing cached metadata to speed up the operation.
* Returns the updated Table object or null if no table with this name exists in the catalog. If
* the existing table is dropped or modified (indicated by the catalog version changing) while the
* reload is in progress, the loaded value will be discarded and the current cached value will be
* returned. This may mean that a missing table (not yet loaded table) will be returned.
*/
public Table reloadTable(TTableName tblName) throws CatalogException {
LOG.debug(
String.format(
"Refreshing table metadata: %s.%s", tblName.getDb_name(), tblName.getTable_name()));
long previousCatalogVersion;
TableLoadingMgr.LoadRequest loadReq;
catalogLock_.readLock().lock();
try {
Table tbl = getTable(tblName.getDb_name(), tblName.getTable_name());
if (tbl == null) return null;
previousCatalogVersion = tbl.getCatalogVersion();
loadReq = tableLoadingMgr_.loadAsync(tblName, tbl);
} finally {
catalogLock_.readLock().unlock();
}
Preconditions.checkNotNull(loadReq);
try {
return replaceTableIfUnchanged(loadReq.get(), previousCatalogVersion);
} finally {
loadReq.close();
}
}
/**
* Gets the table with the given name, loading it if needed (if the existing catalog object is not
* yet loaded). Returns the matching Table or null if no table with this name exists in the
* catalog. If the existing table is dropped or modified (indicated by the catalog version
* changing) while the load is in progress, the loaded value will be discarded and the current
* cached value will be returned. This may mean that a missing table (not yet loaded table) will
* be returned.
*/
public Table getOrLoadTable(String dbName, String tblName) throws CatalogException {
TTableName tableName = new TTableName(dbName.toLowerCase(), tblName.toLowerCase());
TableLoadingMgr.LoadRequest loadReq;
long previousCatalogVersion;
// Return the table if it is already loaded or submit a new load request.
catalogLock_.readLock().lock();
try {
Table tbl = getTable(dbName, tblName);
if (tbl == null || tbl.isLoaded()) return tbl;
previousCatalogVersion = tbl.getCatalogVersion();
loadReq = tableLoadingMgr_.loadAsync(tableName, null);
} finally {
catalogLock_.readLock().unlock();
}
Preconditions.checkNotNull(loadReq);
try {
// The table may have been dropped/modified while the load was in progress, so only
// apply the update if the existing table hasn't changed.
return replaceTableIfUnchanged(loadReq.get(), previousCatalogVersion);
} finally {
loadReq.close();
}
}
/**
* 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;
}
}
/** Resets this catalog instance by clearing all cached table and database metadata. */
public void reset() throws CatalogException {
// First update the policy metadata.
if (sentryProxy_ != null) {
// Sentry Service is enabled.
try {
// Update the authorization policy, waiting for the result to complete.
sentryProxy_.refresh();
} catch (Exception e) {
throw new CatalogException("Error updating authorization policy: ", e);
}
}
catalogLock_.writeLock().lock();
try {
nextTableId_.set(0);
// Since UDFs/UDAs are not persisted in the metastore, we won't clear
// them across reset. To do this, we store all the functions before
// clearing and restore them after.
// TODO: Everything about this. Persist them.
List<Pair<String, HashMap<String, List<Function>>>> functions = Lists.newArrayList();
for (Db db : dbCache_.get().values()) {
if (db.numFunctions() == 0) continue;
functions.add(Pair.create(db.getName(), db.getAllFunctions()));
}
// Build a new DB cache, populate it, and replace the existing cache in one
// step.
ConcurrentHashMap<String, Db> newDbCache = new ConcurrentHashMap<String, Db>();
List<TTableName> tblsToBackgroundLoad = Lists.newArrayList();
MetaStoreClient msClient = metaStoreClientPool_.getClient();
try {
for (String dbName : msClient.getHiveClient().getAllDatabases()) {
Db db = new Db(dbName, this);
db.setCatalogVersion(incrementAndGetCatalogVersion());
newDbCache.put(db.getName().toLowerCase(), db);
for (String tableName : msClient.getHiveClient().getAllTables(dbName)) {
Table incompleteTbl =
IncompleteTable.createUninitializedTable(getNextTableId(), db, tableName);
incompleteTbl.setCatalogVersion(incrementAndGetCatalogVersion());
db.addTable(incompleteTbl);
if (loadInBackground_) {
tblsToBackgroundLoad.add(
new TTableName(dbName.toLowerCase(), tableName.toLowerCase()));
}
}
}
} finally {
msClient.release();
}
// Restore UDFs/UDAs.
for (Pair<String, HashMap<String, List<Function>>> dbFns : functions) {
Db db = null;
try {
db = newDbCache.get(dbFns.first);
} catch (Exception e) {
continue;
}
if (db == null) {
// DB no longer exists - it was probably dropped externally.
// TODO: We could restore this DB and then add the functions back?
continue;
}
for (List<Function> fns : dbFns.second.values()) {
for (Function fn : fns) {
if (fn.getBinaryType() == TFunctionBinaryType.BUILTIN) continue;
fn.setCatalogVersion(incrementAndGetCatalogVersion());
db.addFunction(fn);
}
}
}
dbCache_.set(newDbCache);
addDb(builtinsDb_);
// Submit tables for background loading.
for (TTableName tblName : tblsToBackgroundLoad) {
tableLoadingMgr_.backgroundLoad(tblName);
}
} catch (Exception e) {
LOG.error(e);
throw new CatalogException("Error initializing Catalog. Catalog may be empty.", e);
} finally {
catalogLock_.writeLock().unlock();
}
}
/**
* Adds a list of cache directive IDs for the given table name. Asynchronously refreshes the table
* metadata once all cache directives complete.
*/
public void watchCacheDirs(List<Long> dirIds, TTableName tblName) {
tableLoadingMgr_.watchCacheDirs(dirIds, tblName);
}
