[ 
https://issues.apache.org/jira/browse/HIVE-27186?focusedWorklogId=857927&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-857927
 ]

ASF GitHub Bot logged work on HIVE-27186:
-----------------------------------------

                Author: ASF GitHub Bot
            Created on: 19/Apr/23 12:34
            Start Date: 19/Apr/23 12:34
    Worklog Time Spent: 10m 
      Work Description: dengzhhu653 commented on code in PR #4194:
URL: https://github.com/apache/hive/pull/4194#discussion_r1171268251


##########
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/JdoPropertyStore.java:
##########
@@ -0,0 +1,154 @@
+/*
+ * 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.hadoop.hive.metastore;
+
+import org.apache.commons.jexl3.JexlException;
+import org.apache.hadoop.hive.metastore.RawStore;
+import org.apache.hadoop.hive.metastore.api.MetaException;
+import org.apache.hadoop.hive.metastore.model.MMetastoreDBProperties;
+import org.apache.hadoop.hive.metastore.properties.PropertyException;
+import org.apache.hadoop.hive.metastore.properties.PropertyMap;
+import org.apache.hadoop.hive.metastore.properties.PropertySchema;
+import org.apache.hadoop.hive.metastore.properties.PropertyStore;
+
+import java.util.Iterator;
+import java.util.Map;
+import java.util.UUID;
+import java.util.function.Function;
+import java.util.function.Predicate;
+
+/**
+ * Implementation of the property store delegating persistence to a (jdo) raw 
store.
+ */
+public class JdoPropertyStore extends PropertyStore {
+  /** The jdo objects store. */
+  private final RawStore objectStore;
+
+  /**
+   * Basic ctor.
+   * @param store the object store
+   */
+  public JdoPropertyStore(RawStore store) {
+    this.objectStore = store;
+  }
+
+  @Override
+  public PropertyMap fetchProperties(final String mapKey, Function<String, 
PropertySchema> getSchema) {
+    try {
+      return objectStore.getProperties(mapKey, getPropertyMapFunction(null, 
getSchema));

Review Comment:
   we can move the logic of `objectStore.getProperties` to here. For example:
   ```
   JdoPropertyStore(RawStore store, PersistenceManager pm) 
   
   store.openTransaction()
   try {
     // logic
    store.commitTransaction
   }  finally {
     //... 
   }
   ```





Issue Time Tracking
-------------------

    Worklog Id:     (was: 857927)
    Time Spent: 2h 20m  (was: 2h 10m)

> A persistent property store 
> ----------------------------
>
>                 Key: HIVE-27186
>                 URL: https://issues.apache.org/jira/browse/HIVE-27186
>             Project: Hive
>          Issue Type: Improvement
>          Components: Metastore
>    Affects Versions: 4.0.0-alpha-2
>            Reporter: Henri Biestro
>            Assignee: Henri Biestro
>            Priority: Major
>              Labels: pull-request-available
>          Time Spent: 2h 20m
>  Remaining Estimate: 0h
>
> WHAT
> A persistent property store usable as a support facility for any metadata 
> augmentation feature.
> WHY
> When adding new meta-data oriented features, we usually need to persist 
> information linking the feature data and the HiveMetaStore objects it applies 
> to. Any information related to a database, a table or the cluster - like 
> statistics for example or any operational data state or data (think rolling 
> backup) -  fall in this use-case.
> Typically, accommodating such a feature requires modifying the Metastore 
> database schema by adding or altering a table. It also usually implies 
> modifying the thrift APIs to expose such meta-data to consumers.
> The proposed feature wants to solve the persistence and query/transport for 
> these types of use-cases by exposing a 'key/(meta)value' store exposed as a 
> property system.
> HOW
> A property-value model is the simple and generic exposed API.
> To provision for several usage scenarios, the model entry point is a 
> 'namespace' that qualifies the feature-component property manager. For 
> example, 'stats' could be the namespace for all properties related to the 
> 'statistics' feature.
> The namespace identifies a manager that handles property-groups persisted as 
> property-maps. For instance, all statistics pertaining to a given table would 
> be collocated in the same property-group. As such, all properties (say number 
> of 'unique_values' per columns) for a given HMS table 'relation0' would all 
> be stored and persisted in the same property-map instance.
> Property-maps may be decorated by an (optional) schema that may declare the 
> name and value-type of allowed properties (and their optional default value). 
> Each property is addressed by a name, a path uniquely identifying the 
> property in a given property map.
> The manager also handles transforming property-map names to the property-map 
> keys used to persist them in the DB.
> The API provides inserting/updating properties in bulk transactionally. It 
> also provides selection/projection to help reduce the volume of exchange 
> between client/server; selection can use (JEXL expression) predicates to 
> filter maps.



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