[
https://issues.apache.org/jira/browse/DRILL-5089?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16250388#comment-16250388
]
ASF GitHub Bot commented on DRILL-5089:
---------------------------------------
Github user paul-rogers commented on a diff in the pull request:
https://github.com/apache/drill/pull/1032#discussion_r150678680
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/planner/sql/DynamicRootSchema.java
---
@@ -0,0 +1,125 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.drill.exec.planner.sql;
+
+import com.google.common.collect.ImmutableSortedSet;
+import com.google.common.collect.Lists;
+import com.google.common.collect.Sets;
+import org.apache.calcite.DataContext;
+import org.apache.calcite.jdbc.CalciteRootSchema;
+import org.apache.calcite.jdbc.CalciteSchema;
+
+import org.apache.calcite.linq4j.tree.Expression;
+import org.apache.calcite.linq4j.tree.Expressions;
+import org.apache.calcite.schema.SchemaPlus;
+import org.apache.calcite.schema.impl.AbstractSchema;
+import org.apache.calcite.util.BuiltInMethod;
+import org.apache.calcite.util.Compatible;
+import org.apache.drill.common.exceptions.ExecutionSetupException;
+import org.apache.drill.exec.store.SchemaConfig;
+import org.apache.drill.exec.store.StoragePlugin;
+import org.apache.drill.exec.store.StoragePluginRegistry;
+import org.apache.drill.exec.store.SubSchemaWrapper;
+
+import java.io.IOException;
+import java.util.Map;
+import java.util.NavigableSet;
+import java.util.Set;
+
+public class DynamicRootSchema extends DynamicSchema
+ implements CalciteRootSchema {
+
+ /** Creates a root schema. */
+ DynamicRootSchema(StoragePluginRegistry storages, SchemaConfig
schemaConfig) {
+ super(null, new RootSchema(), "");
+ this.schemaConfig = schemaConfig;
+ this.storages = storages;
+ }
+
+ @Override
+ public CalciteSchema getSubSchema(String schemaName, boolean
caseSensitive) {
+ CalciteSchema retSchema = getSubSchemaMap().get(schemaName);
+
+ if (retSchema == null) {
+ loadSchemaFactory(schemaName, caseSensitive);
+ }
+
+ retSchema = getSubSchemaMap().get(schemaName);
+ return retSchema;
--- End diff --
if the original call returns non-null, we make the same call a second time.
Better:
```
retSchema = ...
if (retSchema != null) { return retSchema; }
loadSchemaFactory(...)
return getSubSchemaMap()...
```
> Skip initializing all enabled storage plugins for every query
> -------------------------------------------------------------
>
> Key: DRILL-5089
> URL: https://issues.apache.org/jira/browse/DRILL-5089
> Project: Apache Drill
> Issue Type: Improvement
> Components: Query Planning & Optimization
> Affects Versions: 1.9.0
> Reporter: Abhishek Girish
> Assignee: Chunhui Shi
> Priority: Critical
>
> In a query's lifecycle, at attempt is made to initialize each enabled storage
> plugin, while building the schema tree. This is done regardless of the actual
> plugins involved within a query.
> Sometimes, when one or more of the enabled storage plugins have issues -
> either due to misconfiguration or the underlying datasource being slow or
> being down, the overall query time taken increases drastically. Most likely
> due the attempt being made to register schemas from a faulty plugin.
> For example, when a jdbc plugin is configured with SQL Server, and at one
> point the underlying SQL Server db goes down, any Drill query starting to
> execute at that point and beyond begin to slow down drastically.
> We must skip registering unrelated schemas (& workspaces) for a query.
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