[GitHub] [cassandra] pauloricardomg commented on a diff in pull request #2117: Add a virtual table to list snapshots for CASSANDRA-18102

["pauloricardomg (via GitHub)" <gi...@apache.org>]

pauloricardomg commented on code in PR #2117:
URL: https://github.com/apache/cassandra/pull/2117#discussion_r1118119607


##########
src/java/org/apache/cassandra/db/virtual/SnapshotsTable.java:
##########
@@ -0,0 +1,93 @@
+/*
+ * 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.cassandra.db.virtual;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import javax.management.openmbean.TabularData;
+import javax.management.openmbean.TabularDataSupport;
+import com.google.common.collect.ImmutableMap;
+
+import org.apache.cassandra.db.SnapshotDetailsTabularData;
+import org.apache.cassandra.db.marshal.BooleanType;
+import org.apache.cassandra.db.marshal.LongType;
+import org.apache.cassandra.db.marshal.UTF8Type;
+import org.apache.cassandra.dht.LocalPartitioner;
+import org.apache.cassandra.schema.TableMetadata;
+import org.apache.cassandra.service.StorageService;
+
+public class SnapshotsTable extends AbstractVirtualTable
+{
+    private static final String SNAPSHOT_NAME = "snapshot_name";
+    private static final String KEYSPACE_NAME = "keyspace_name";
+    private static final String COLUMNFAMILY_NAME = "columnfamily_name";
+    private static final String TRUE_SIZE = "true_size";
+    private static final String SIZE_ON_DISK = "size_on_disk";
+    private static final String CREATE_TIME = "created_at";
+    private static final String EXPIRATION_TIME = "expires_at";
+    private static final String EPHEMERAL = "ephemeral";
+    
+    SnapshotsTable(String keyspace)
+    {
+        super(TableMetadata.builder(keyspace, "snapshots")
+                           .comment("tables snapshots")
+                           .kind(TableMetadata.Kind.VIRTUAL)
+                           .partitioner(new LocalPartitioner(UTF8Type.instance))
+                           .addPartitionKeyColumn(SNAPSHOT_NAME, UTF8Type.instance)

Review Comment:
   Sorry for the delay - have been busy in the past couple of weeks but will try to be faster on next iterations so we can wrap this up soon.
   
   I agree with with @smiklosovic comment about using more succint column names (ie. `keyspace` vs `keyspace_name` and `table` vs `columnfamily_name`), but I think we should use the column name "tag" and not "name" to refer to a snapshot identifier, and keep this as table partition key. We should enable allow filtering on this virtual table (with [CASSANDRA-18271](https://issues.apache.org/jira/browse/CASSANDRA-18271) to allow querying by non partition keys (ie. `keyspace` or `table`). This would allow the following queries:
   
   ```sql
   use system_views;
   select * from snapshots;
   select * from snapshots where tag = "mysnapshot" # query by partition key
   select * from snapshots where keyspace = 'ks1'; # query by non-partition keys
   select * from snapshots where keyspace = 'ks1' and table = 'tb1';
   select * from snapshots where keyspace = 'ks1' and table = 'tb1' and tag = "mysnapshot";
   ```
   
   What do you think?
   



-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: pr-unsubscribe@cassandra.apache.org

For queries about this service, please contact Infrastructure at:
users@infra.apache.org


---------------------------------------------------------------------
To unsubscribe, e-mail: pr-unsubscribe@cassandra.apache.org
For additional commands, e-mail: pr-help@cassandra.apache.org