Hazelcast MapStoreConfig被忽略 [英] Hazelcast MapStoreConfig ignored

问题描述

我正在使用地图存储将hazelcast分布式地图保存在数据库中.

I'm using a map store to persist my hazelcast distributed map in a database.

在我的测试案例中，我启动了三个hazelcast实例，每个实例的配置方式相同:

In my test case, I start three hazelcast instances, each configured the same way:

Config cfg = new Config();
cfg.setInstanceName("name");
hazelcast = Hazelcast.newHazelcastInstance(cfg);    
MapConfig mapConfig = new MapConfig("myMapName");
MapStoreConfig mapStoreConfig = new MapStoreConfig();
mapStoreConfig.setClassName(MyMapStore.class.getName());
mapStoreConfig.setWriteDelaySeconds(0);
mapStoreConfig.setEnabled(true);
mapConfig.setMapStoreConfig(mapStoreConfig);
mapConfig.setBackupCount(2);
hazelcast.getConfig().addMapConfig(mapConfig);
IMap myMap = hazelcast.getMap("myMapName");

但是，当我向地图添加值时，只有第一个Cluster成员写入数据库时​​，MapStoreConfig才在每个其他节点上都设置为Default values. 但是，如果我将代码更改为以下代码，那么它将起作用:

However, when I add values to the map, only the first Cluster member writes into the database, the MapStoreConfig is just set to Default values on each other node. But, if I change the code to the following, it works:

Config cfg = new Config();
cfg.setInstanceName("name");
MapConfig mapConfig = new MapConfig("myMapName");
MapStoreConfig mapStoreConfig = new MapStoreConfig();
mapStoreConfig.setClassName(MyMapStore.class.getName());
mapStoreConfig.setWriteDelaySeconds(0);
mapStoreConfig.setEnabled(true);
mapConfig.setMapStoreConfig(mapStoreConfig);
mapConfig.setBackupCount(2);
cfg.addMapConfig(mapConfig);
hazelcast = Hazelcast.newHazelcastInstance(cfg);
IMap myMap = hazelcast.getMap("myMapName");

似乎忽略了行hazelcast.getConfig().addMapConfig(mapConfig);. 经过hazelcast v3.1.5的测试.

Seems like the line hazelcast.getConfig().addMapConfig(mapConfig); is ignored. Tested with hazelcast v3.1.5.

推荐答案

据我了解，Config实例应仅被视为一种模板"，用于创建一个实例，但此后可能无法用于修改.尽管根据快速的网络搜索和对文档的了解，并没有明确说明，但是

To my understanding, the Config instance should be considered only as a sort of "template", which is used to create one instance, but may not be used to afterwards modify this instance. Although, according to a quick websearch and a look at the documentation, this is not stated explicitly, but

1. 到目前为止，我所看到的所有示例都遵循FIRST创建和完整Config的模式，然后再创建相应的实例，
2. addMapConfig方法(在 https://github.com/hazelcast/hazelcast/blob/master/hazelcast/src/main/java/com/hazelcast/config/Config.java )不涉及任何通知机制.因此，至少必须有某种机制可以通知Hazelcast实例有关已更改的配置，但是我认为这样的机制不存在.

1. all examples that I have seen so far follow the pattern of FIRST creating and the complete Config, and THEN creating the corresponding instance and
2. the addMapConfig method (in https://github.com/hazelcast/hazelcast/blob/master/hazelcast/src/main/java/com/hazelcast/config/Config.java ) does not involve any notification mechanism. So there would at least have to be some mechanism to inform the Hazelcast instance about the changed config, but I think that such a mechanism does not exist.

根据我在源代码中所读的内容(例如，在 https://github.com /hazelcast/hazelcast/blob/master/hazelcast/src/main/java/com/hazelcast/instance/HazelcastInstanceImpl.java )，该配置文件在构造时仅 read ，并且创建Hazelcast实例后，似乎不可能在 后更改配置.

From what I have read in the source code ( e.g. in https://github.com/hazelcast/hazelcast/blob/master/hazelcast/src/main/java/com/hazelcast/instance/Node.java and https://github.com/hazelcast/hazelcast/blob/master/hazelcast/src/main/java/com/hazelcast/instance/HazelcastInstanceImpl.java ), the Config is only read at construction time, and it does not seem to be possible to change the configuration after the Hazelcast instance has been created.

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