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https://issues.apache.org/jira/browse/DRILL-5089?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15942170#comment-15942170
]
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/795#discussion_r108052385
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/planner/sql/DrillCatalogReader.java
---
@@ -0,0 +1,180 @@
+/**
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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.base.Joiner;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.Lists;
+import com.google.common.collect.Sets;
+import org.apache.calcite.adapter.java.JavaTypeFactory;
+import org.apache.calcite.jdbc.CalciteSchema;
+import org.apache.calcite.jdbc.CalciteSchemaImpl;
+import org.apache.calcite.jdbc.SimpleCalciteSchema;
+import org.apache.calcite.prepare.CalciteCatalogReader;
+import org.apache.calcite.prepare.RelOptTableImpl;
+import org.apache.calcite.schema.SchemaPlus;
+import org.apache.drill.common.config.DrillConfig;
+import org.apache.drill.common.exceptions.UserException;
+import org.apache.drill.exec.ops.QueryContext;
+import org.apache.drill.exec.store.SchemaConfig;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Implementation of {@link
org.apache.calcite.prepare.Prepare.CatalogReader}
--- End diff --
Maybe explain the purpose and not just the implementation? What part of
query processing does this address? Does this resolve references to schemas and
workspaces? Then the schema resolves the reference to a table name?
> 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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