Examples with IMetaStoreClient org.apache.hadoop.hive.metastore.IMetaStoreClient used on opensource projects

Example 41 with IMetaStoreClient

use of org.apache.hadoop.hive.metastore.IMetaStoreClient in project cdap by caskdata.

the class BaseHiveExploreService method getMetaStoreClient.

private IMetaStoreClient getMetaStoreClient() throws ExploreException {
    if (metastoreClientLocal.get() == null) {
        try {
            IMetaStoreClient client = new HiveMetaStoreClient(getHiveConf());
            Supplier<IMetaStoreClient> supplier = Suppliers.ofInstance(client);
            metastoreClientLocal.set(supplier);
            // We use GC of the supplier as a signal for us to know that a thread is gone
            // The supplier is set into the thread local, which will get GC'ed when the thread is gone.
            // Since we use a weak reference key to the supplier that points to the client
            // (in the metastoreClientReferences map), it won't block GC of the supplier instance.
            // We can use the weak reference, which is retrieved through polling the ReferenceQueue,
            // to get back the client and call close() on it.
            metastoreClientReferences.put(new WeakReference<>(supplier, metastoreClientReferenceQueue), client);
        } catch (MetaException e) {
            throw new ExploreException("Error initializing Hive Metastore client", e);
        }
    }
    return metastoreClientLocal.get().get();
}