Github user jacques-n commented on a diff in the pull request:
https://github.com/apache/drill/pull/443#discussion_r58974382
--- Diff:
contrib/storage-hbase/src/main/java/org/apache/drill/exec/store/hbase/HBaseStoragePlugin.java
---
@@ -19,36 +19,75 @@
import java.io.IOException;
import java.util.Set;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
import org.apache.calcite.schema.SchemaPlus;
-
import org.apache.drill.common.JSONOptions;
+import org.apache.drill.common.exceptions.UserException;
import org.apache.drill.exec.ops.OptimizerRulesContext;
import org.apache.drill.exec.server.DrillbitContext;
import org.apache.drill.exec.store.AbstractStoragePlugin;
import org.apache.drill.exec.store.SchemaConfig;
import org.apache.drill.exec.store.StoragePluginOptimizerRule;
+import org.apache.hadoop.hbase.client.Connection;
+import org.apache.hadoop.hbase.client.ConnectionFactory;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
+import com.google.common.cache.RemovalListener;
+import com.google.common.cache.RemovalNotification;
import com.google.common.collect.ImmutableSet;
+import com.google.common.util.concurrent.UncheckedExecutionException;
public class HBaseStoragePlugin extends AbstractStoragePlugin {
- static final org.slf4j.Logger logger =
org.slf4j.LoggerFactory.getLogger(HBaseStoragePlugin.class);
+ private static final org.slf4j.Logger logger =
org.slf4j.LoggerFactory.getLogger(HBaseStoragePlugin.class);
private final DrillbitContext context;
- private final HBaseStoragePluginConfig engineConfig;
+ private final HBaseStoragePluginConfig storeConfig;
private final HBaseSchemaFactory schemaFactory;
@SuppressWarnings("unused")
private final String name;
- public HBaseStoragePlugin(HBaseStoragePluginConfig configuration,
DrillbitContext context, String name)
+ private final LoadingCache<Integer, Connection> connectionCache;
+
+ public HBaseStoragePlugin(HBaseStoragePluginConfig storeConfig,
DrillbitContext context, String name)
throws IOException {
this.context = context;
this.schemaFactory = new HBaseSchemaFactory(this, name);
- this.engineConfig = configuration;
+ this.storeConfig = storeConfig;
this.name = name;
+
+ this.connectionCache = CacheBuilder.newBuilder()
+ .expireAfterAccess(24, TimeUnit.HOURS)
+ .removalListener(new RemovalListener<Integer, Connection>() {
+ @Override
+ public void onRemoval(RemovalNotification<Integer, Connection>
notification) {
+ try {
+ notification.getValue().close();
+ logger.debug("HBase connection '{}' closed.",
notification.getValue());
+ } catch (Throwable t) {
+ logger.warn("Error while closing HBase connection.", t);
+ }
+ }
+ })
+ .build(new CacheLoader<Integer, Connection>() {
+ @Override
+ public synchronized Connection load(Integer key /* ignored */)
throws Exception {
+ if (connection == null
+ || connection.isAborted()
+ || connection.isClosed()) {
+ connection =
ConnectionFactory.createConnection(HBaseStoragePlugin.this.storeConfig.getHBaseConf());
+ logger.debug("HBase connection '{}' created.", connection);
+ }
+ return connection;
+ }
+ private Connection connection = null;
--- End diff --
Why is this an instance field and not protected? Since the cache loader is
already managing a single instance, it doesn't seem like we need to worry about
ensuring a singleton. Separately, since we're behind a cache, we won't call
connection.isAborted(). Should we make sure that the get() checks isAborted()
and isClosed()
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