MongoDB标记范围不工作

Question

我的MongoDB有点问题。这是我的配置：

mongos> sh.status()
    --- Sharding Status --- 
      sharding version: {
            "_id" : 1,
            "version" : 4,
            "minCompatibleVersion" : 4,
            "currentVersion" : 5,
            "clusterId" : ObjectId("546f2d9c37d2895f3b8f9ec1")
    }
      shards:
            {  "_id" : "site_A_shard_1",  "host" : "site_A_shard_1/<HOST1>:27510,<HOST2>:27511",  "tags" : [ "site_A" ] }
            {  "_id" : "site_A_shard_2",  "host" : "site_A_shard_2/<HOST2>:27521,<HOST1>:27520",  "tags" : [ "site_A" ] }
            {  "_id" : "site_B_shard_1",  "host" : "site_B_shard_1/<HOST3>:27510,<HOST4>:27511",  "tags" : [ "site_B" ] }
            {  "_id" : "site_B_shard_2",  "host" : "site_B_shard_2/<HOST4>:27521,<HOST3>:27520",  "tags" : [ "site_B" ] }
      databases:
            {  "_id" : "admin",  "partitioned" : false,  "primary" : "config" }
            {  "_id" : "test",  "partitioned" : false,  "primary" : "site_B_shard_1" }
            {  "_id" : "ocs",  "partitioned" : true,  "primary" : "site_B_shard_1" }
                    ocs.adrs_queue
                            shard key: { "shard.target" : 1, "shard.key" : 1 }
                            { "shard.target" : { "$minKey" : 1 }, "shard.key" : { "$minKey" : 1 } } -->> { "shard.target" : { "$maxKey" : 1 }, "shard.key" : { "$maxKey" : 1 } } on : site_B_shard_1 Timestamp(1, 0) 
                             tag: site_A  { "shard" : { "target" : "siteA", "key" : { "$minKey" : 1 } } } -->> { "shard" : { "target" : "siteA", "key" : { "$maxKey" : 1 } } }
                             tag: site_B  { "shard" : { "target" : "siteB", "key" : { "$minKey" : 1 } } } -->> { "shard" : { "target" : "siteB", "key" : { "$maxKey" : 1 } } }
                    ocs.ldrs
                            shard key: { "shard.target" : 1, "shard.key" : 1 }
                            { "shard.target" : { "$minKey" : 1 }, "shard.key" : { "$minKey" : 1 } } -->> { "shard.target" : { "$maxKey" : 1 }, "shard.key" : { "$maxKey" : 1 } } on : site_B_shard_1 Timestamp(1, 0) 
                             tag: site_A  { "shard" : { "target" : "siteA", "key" : { "$minKey" : 1 } } } -->> { "shard" : { "target" : "siteA", "key" : { "$maxKey" : 1 } } }
                             tag: site_B  { "shard" : { "target" : "siteB", "key" : { "$minKey" : 1 } } } -->> { "shard" : { "target" : "siteB", "key" : { "$maxKey" : 1 } } }
                    ocs.notifs_queue
                            shard key: { "shard.target" : 1, "shard.key" : 1 }
                            { "shard.target" : { "$minKey" : 1 }, "shard.key" : { "$minKey" : 1 } } -->> { "shard.target" : { "$maxKey" : 1 }, "shard.key" : { "$maxKey" : 1 } } on : site_B_shard_1 Timestamp(1, 0) 
                             tag: site_A  { "shard" : { "target" : "siteA", "key" : { "$minKey" : 1 } } } -->> { "shard" : { "target" : "siteA", "key" : { "$maxKey" : 1 } } }
                             tag: site_B  { "shard" : { "target" : "siteB", "key" : { "$minKey" : 1 } } } -->> { "shard" : { "target" : "siteB", "key" : { "$maxKey" : 1 } } }
                    ocs.ss_queue
                            shard key: { "shard.target" : 1, "shard.key" : 1 }
                            { "shard.target" : { "$minKey" : 1 }, "shard.key" : { "$minKey" : 1 } } -->> { "shard.target" : { "$maxKey" : 1 }, "shard.key" : { "$maxKey" : 1 } } on : site_B_shard_1 Timestamp(1, 0) 
                             tag: site_A  { "shard" : { "target" : "siteA", "key" : { "$minKey" : 1 } } } -->> { "shard" : { "target" : "siteA", "key" : { "$maxKey" : 1 } } }
                             tag: site_B  { "shard" : { "target" : "siteB", "key" : { "$minKey" : 1 } } } -->> { "shard" : { "target" : "siteB", "key" : { "$maxKey" : 1 } } }

在配置标记范围时，它似乎不起作用。每次我尝试插入一些信息时，它都会存储在同一个碎片(site_B_shard_1)中，即使相关的标记是site_A。

我做错了什么？

Answer 1

看起来，您试图跨两个碎片分发单个集合，但定义了重叠的碎片标签范围，其中site_A和site_B包含整个shard.target键值(minkey .. maxkey)：

tag: site_A  {
    "shard" : {
        "target" : "siteA",
        "key" : { "$minKey" : 1 }
    }
} -->> {
    "shard" : {
        "target" : "siteA",
        "key" : { "$maxKey" : 1 }
    }
}

tag: site_B  {
    "shard" : {
        "target" : "siteB",
        "key" : { "$minKey" : 1 }
    }
} -->> {
    "shard" : {
        "target" : "siteB",
        "key" : { "$maxKey" : 1 }
    }
}

如果要使用标记感知切分在集合中分发数据，则需要定义范围，其中下限是包含的，上限是独占的，例如：

sh.addTagRange('ocs.adrs_queue'，{"shard.target":MinKey}，{"shard.target":"site_A"}，'site_A') sh.addTagRange('ocs.adrs_queue'，{"shard.target":"site_A"}，{"shard.target":"site_B"}，'site_A') sh.addTagRange('ocs.adrs_queue'，{"shard.target":"site_B"}，{"shard.target":MaxKey}，'site_B')

在这一设置中：

• 应该将具有匹配shard.target值的site_A和site_B的文档分发到匹配的碎片中
• shard.target值小于site_A的文档也将在site_A碎片上分发。
• shard.target值大于site_B的文档将在site_B碎片上分发

有关标记感知切分和多数据中心部署的更多示例，请参见：

• 如何平衡共享群集的集合
• MongoDB中的分层存储模型:优化延迟和成本
• 关于多直流部署的MongoDB白皮书