MySQL 與 Elasticsearch 數據不對稱問題解決辦法
jdbc-input-plugin 只能實現數據庫的追加，對于 elasticsearch 增量寫入，但經常jdbc源一端的數據庫可能會做數據庫刪除或者更新操作。這樣一來數據庫與搜索引擎的數據庫就出現了不對稱的情況。
當然你如果有開發團隊可以寫程序在刪除或者更新的時候同步對搜索引擎操作。如果你沒有這個能力，可以嘗試下面的方法。
這里有一個數據表 article , mtime 字段定義了 ON UPDATE CURRENT_TIMESTAMP 所以每次更新mtime的時間都會變化
mysql> desc article;+-------------+--------------+------+-----+--------------------------------+-------+| Field | Type | Null | Key | Default | Extra |+-------------+--------------+------+-----+--------------------------------+-------+| id | int(11) | NO | | 0 | || title | mediumtext | NO | | NULL | || description | mediumtext | YES | | NULL | || author | varchar(100) | YES | | NULL | || source | varchar(100) | YES | | NULL | || content | longtext | YES | | NULL | || status | enum('Y','N')| NO | | 'N' | || ctime | timestamp | NO | | CURRENT_TIMESTAMP | || mtime | timestamp | YES | | ON UPDATE CURRENT_TIMESTAMP | |+-------------+--------------+------+-----+--------------------------------+-------+7 rows in set (0.00 sec)logstash 增加 mtime 的查詢規則
jdbc { jdbc_driver_library => "/usr/share/java/mysql-connector-java.jar" jdbc_driver_class => "com.mysql.jdbc.Driver" jdbc_connection_string => "jdbc:mysql://localhost:3306/cms" jdbc_user => "cms" jdbc_password => "password" schedule => "* * * * *" #定時cron的表達式,這里是每分鐘執行一次 statement => "select * from article where mtime > :sql_last_value" use_column_value => true tracking_column => "mtime" tracking_column_type => "timestamp" record_last_run => true last_run_metadata_path => "/var/tmp/article-mtime.last" }創建回收站表，這個事用于解決數據庫刪除，或者禁用 status = 'N' 這種情況的。
CREATE TABLE `elasticsearch_trash` ( `id` int(11) NOT NULL, `ctime` timestamp NULL DEFAULT CURRENT_TIMESTAMP, PRIMARY KEY (`id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8
為 article 表創建觸發器
CREATE DEFINER=`dba`@`%` TRIGGER `article_BEFORE_UPDATE` BEFORE UPDATE ON `article` FOR EACH ROWBEGIN -- 此處的邏輯是解決文章狀態變為 N 的時候，需要將搜索引擎中對應的數據刪除。 IF NEW.status = 'N' THEN insert into elasticsearch_trash(id) values(OLD.id); END IF; -- 此處邏輯是修改狀態到 Y 的時候，方式elasticsearch_trash仍然存在該文章ID，導致誤刪除。所以需要刪除回收站中得回收記錄。 IF NEW.status = 'Y' THEN delete from elasticsearch_trash where id = OLD.id; END IF;ENDCREATE DEFINER=`dba`@`%` TRIGGER `article_BEFORE_DELETE` BEFORE DELETE ON `article` FOR EACH ROWBEGIN -- 此處邏輯是文章被刪除同事將改文章放入搜索引擎回收站。 insert into elasticsearch_trash(id) values(OLD.id);END
接下來我們需要寫一個簡單地 Shell 每分鐘運行一次，從 elasticsearch_trash 數據表中取出數據，然后使用 curl 命令調用 elasticsearch restful 接口，刪除被收回的數據。
你還可以開發相關的程序，這里提供一個 Spring boot 定時任務例子。
實體
package cn.netkiller.api.domain.elasticsearch;import java.util.Date;import javax.persistence.Column;import javax.persistence.Entity;import javax.persistence.Id;import javax.persistence.Table;@Entity@Tablepublic class ElasticsearchTrash { @Id private int id; @Column(columnDefinition = "TIMESTAMP DEFAULT CURRENT_TIMESTAMP") private Date ctime; public int getId() { return id; } public void setId(int id) { this.id = id; } public Date getCtime() { return ctime; } public void setCtime(Date ctime) { this.ctime = ctime; }}倉庫
package cn.netkiller.api.repository.elasticsearch;import org.springframework.data.repository.CrudRepository;import com.example.api.domain.elasticsearch.ElasticsearchTrash;public interface ElasticsearchTrashRepository extends CrudRepository<ElasticsearchTrash, Integer>{}定時任務
package cn.netkiller.api.schedule;import org.elasticsearch.action.delete.DeleteResponse;import org.elasticsearch.client.transport.TransportClient;import org.elasticsearch.rest.RestStatus;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.scheduling.annotation.Scheduled;import org.springframework.stereotype.Component;import com.example.api.domain.elasticsearch.ElasticsearchTrash;import com.example.api.repository.elasticsearch.ElasticsearchTrashRepository;@Componentpublic class ScheduledTasks { private static final Logger logger = LoggerFactory.getLogger(ScheduledTasks.class); @Autowired private TransportClient client; @Autowired private ElasticsearchTrashRepository alasticsearchTrashRepository; public ScheduledTasks() { } @Scheduled(fixedRate = 1000 * 60) // 60秒運行一次調度任務 public void cleanTrash() { for (ElasticsearchTrash elasticsearchTrash : alasticsearchTrashRepository.findAll()) { DeleteResponse response = client.prepareDelete("information", "article", elasticsearchTrash.getId() + "").get(); RestStatus status = response.status(); logger.info("delete {} {}", elasticsearchTrash.getId(), status.toString()); if (status == RestStatus.OK || status == RestStatus.NOT_FOUND) { alasticsearchTrashRepository.delete(elasticsearchTrash); } } }}Spring boot 啟動主程序。
package cn.netkiller.api;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.scheduling.annotation.EnableScheduling;@SpringBootApplication@EnableSchedulingpublic class Application { public static void main(String[] args) { SpringApplication.run(Application.class, args); }} 以上就是MySQL 與 Elasticsearch 數據不對稱問題解決辦法的講解，如有疑問請留言或者到本站社區交流討論，感謝閱讀，希望能幫助到大家，謝謝大家對本站的支持！
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