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https://issues.apache.org/jira/browse/PHOENIX-4666?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16586505#comment-16586505
]
ASF GitHub Bot commented on PHOENIX-4666:
-----------------------------------------
Github user joshelser commented on a diff in the pull request:
https://github.com/apache/phoenix/pull/298#discussion_r211402317
--- Diff:
phoenix-core/src/it/java/org/apache/phoenix/end2end/join/HashJoinPersistentCacheIT.java
---
@@ -0,0 +1,137 @@
+/*
+ * 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.phoenix.end2end.join;
+
+import static org.apache.phoenix.util.TestUtil.TEST_PROPERTIES;
+import static org.junit.Assert.assertEquals;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.ResultSet;
+import java.util.Properties;
+
+import org.apache.phoenix.end2end.join.HashJoinCacheIT.InvalidateHashCache;
+import org.apache.phoenix.util.PropertiesUtil;
+import org.apache.phoenix.util.SchemaUtil;
+import org.apache.phoenix.util.TestUtil;
+import org.junit.Test;
+
+public class HashJoinPersistentCacheIT extends BaseJoinIT {
+
+ @Override
+ protected String getTableName(Connection conn, String virtualName)
throws Exception {
+ String realName = super.getTableName(conn, virtualName);
+ TestUtil.addCoprocessor(conn,
SchemaUtil.normalizeFullTableName(realName), InvalidateHashCache.class);
+ return realName;
+ }
+
+ @Test
+ public void testPersistentCache() throws Exception {
--- End diff --
This is a very nice test!
> Add a subquery cache that persists beyond the life of a query
> -------------------------------------------------------------
>
> Key: PHOENIX-4666
> URL: https://issues.apache.org/jira/browse/PHOENIX-4666
> Project: Phoenix
> Issue Type: Improvement
> Reporter: Marcell Ortutay
> Assignee: Marcell Ortutay
> Priority: Major
> Attachments: PHOENIX-4666-subquery-cache-4.x-HBase-1.4.patch
>
>
> The user list thread for additional context is here:
> [https://lists.apache.org/thread.html/e62a6f5d79bdf7cd238ea79aed8886816d21224d12b0f1fe9b6bb075@%3Cuser.phoenix.apache.org%3E]
> ----
> A Phoenix query may contain expensive subqueries, and moreover those
> expensive subqueries may be used across multiple different queries. While
> whole result caching is possible at the application level, it is not possible
> to cache subresults in the application. This can cause bad performance for
> queries in which the subquery is the most expensive part of the query, and
> the application is powerless to do anything at the query level. It would be
> good if Phoenix provided a way to cache subquery results, as it would provide
> a significant performance gain.
> An illustrative example:
> SELECT * FROM table1 JOIN (SELECT id_1 FROM large_table WHERE x = 10)
> expensive_result ON table1.id_1 = expensive_result.id_2 AND table1.id_1 =
> \{id}
> In this case, the subquery "expensive_result" is expensive to compute, but it
> doesn't change between queries. The rest of the query does because of the
> \{id} parameter. This means the application can't cache it, but it would be
> good if there was a way to cache expensive_result.
> Note that there is currently a coprocessor based "server cache", but the data
> in this "cache" is not persisted across queries. It is deleted after a TTL
> expires (30sec by default), or when the query completes.
> This is issue is fairly high priority for us at 23andMe and we'd be happy to
> provide a patch with some guidance from Phoenix maintainers. We are currently
> putting together a design document for a solution, and we'll post it to this
> Jira ticket for review in a few days.
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