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sharding sphere 4.0.0-RC1版本 按年分表实战

天尘·云烟 2020-01-07 17:06:00 阅读数:16 评论数:0 点赞数:0 收藏数:0

1. sharding sphere 4.0.0-RC1版本 按年分表实战

1.1. 需求

需要对日志表进行按时间划分表,由于用于后台系统,日志量预估不会太大,因此按年划分表

经过我不断的查阅sharding sphere资料和实践,我最后还是决定先建表,再把actual-data-nodes表结点给定下来,为什么这么说?

我纠结的是到底要不要动态创建表,若想要不自己手动每隔几年维护表,我们当然希望能自动创建。但经过我的实践,sharding sphere本身没有提供该功能,但可以通过分片算法实现类中自定义实现,但前提是我们要随时知道要分片表有几个分片,比如log_2019,log_2020,log_2021,只要我能初始化的时候知道分片有几个表以及表名,那么我就不会查询到不存在的表导致报错,反之则容易报错

我们知道mysql可以通过查询information_schema.TABLES来查询存在的表,但是不知道是不是sharding sphere的bug,我用库名加表名查该库它会强制给我改写成我默认的连接库,导致表不存在,根本查不到

所以我退而求其次,下面我列出我的方案,方案采用的版本是4.0.0-RC1

1.2. 引入pom

  1. 先把pom列出来,只给代码不给pom都是耍流氓
 <!-- 分库分表 -->
<dependency>
<groupId>org.apache.shardingsphere</groupId>
<artifactId>sharding-jdbc-spring-boot-starter</artifactId>
<version>4.0.0-RC1</version>
</dependency>
<dependency>
<groupId>org.apache.shardingsphere</groupId>
<artifactId>sharding-jdbc-spring-namespace</artifactId>
<version>4.0.0-RC1</version>
</dependency>

1.3. application.yml配置

  1. 如下配置,分表最重要的是table-strategy分表策略,sharding-column表示分表字段,当插入查询需要指定哪个分表时,必须带上这个条件,否则可能出错,actual-data-nodes表示你分了哪些表,它有一定语法,如下$->{0..1}表示system_log_2020,system_log_2021两张表,我需要在mysql建好这两张表
spring:
shardingsphere:
props:
sql:
show: true
datasource:
names: ds0
ds0:
type: com.alibaba.druid.pool.DruidDataSource
driver-class-name: com.mysql.cj.jdbc.Driver
url: jdbc:mysql://xxxxx:3306/test?useUnicode=true&characterEncoding=utf-8&serverTimezone=GMT%2B8&allowMultiQueries=true
username: xxx
password: xxx
sharding:
tables:
system_log:
actual-data-nodes: ds0.system_log_202$->{0..1}
table-strategy:
standard:
sharding-column: created
precise-algorithm-class-name: com.xxx.platform.system.log.LogShardingAlgorithm
range-algorithm-class-name: com.xxx.platform.system.log.LogShardingAlgorithm

1.4. 分表策略

  1. 最重要的就是LogShardingAlgorithm这个类
import com.google.common.collect.Range;
import lombok.extern.slf4j.Slf4j;
import org.apache.shardingsphere.api.sharding.standard.PreciseShardingAlgorithm;
import org.apache.shardingsphere.api.sharding.standard.PreciseShardingValue;
import org.apache.shardingsphere.api.sharding.standard.RangeShardingAlgorithm;
import org.apache.shardingsphere.api.sharding.standard.RangeShardingValue;
import java.util.ArrayList;
import java.util.Collection;
/**
* @author: laoliangliang
* @description: 日志分片
* @create: 2020/1/2 10:19
**/
@Slf4j
public class LogShardingAlgorithm implements PreciseShardingAlgorithm, RangeShardingAlgorithm<Integer> {
@Override
public String doSharding(Collection availableTargetNames, PreciseShardingValue shardingValue) {
String target = shardingValue.getValue().toString();
return shardingValue.getLogicTableName() + "_" + target.substring(target.lastIndexOf("_") + 1, target.lastIndexOf("_") + 5);
}
@Override
public Collection<String> doSharding(Collection<String> availableTargetNames, RangeShardingValue<Integer> shardingValue) {
Collection<String> availables = new ArrayList<>();
Range valueRange = shardingValue.getValueRange();
for (String target : availableTargetNames) {
Integer shardValue = Integer.parseInt(target.substring(target.lastIndexOf("_") + 1, target.lastIndexOf("_") + 5));
if (valueRange.hasLowerBound()) {
String lowerStr = valueRange.lowerEndpoint().toString();
Integer start = Integer.parseInt(lowerStr.substring(0, 4));
if (start - shardValue > 0) {
continue;
}
}
if (valueRange.hasUpperBound()) {
String upperStr = valueRange.upperEndpoint().toString();
Integer end = Integer.parseInt(upperStr.substring(0, 4));
if (end - shardValue < 0) {
continue;
}
}
availables.add(target);
}
return availables;
}
}
  1. 我实现了PreciseShardingAlgorithm, RangeShardingAlgorithm这两个接口,分别表示当created条件为=between时会分别进入这两个方法,用来判断sql语句命中哪个表
  2. 这里要注意,created的><大于小于判断是不起效果的,求范围只能用between,如果我说错了请提醒哦
  3. 接下来调用sql语句我是这样写的
SELECT created,user_name,`action`,id FROM system_log
<where>
<if test="id!=null and id!=''">
and pk_id=#{id}
</if>
<if test="startTime != null and endTime != null">
and created BETWEEN #{startTime} and #{endTime}
</if>
</where>
order by created desc

1.5. 结果

  1. mybatis插入后日志如下,可以看到mybatis打印的日志表名还是system_log,但实际对应数据库有system_log_2020,system_log_2021两张表,我插入的时间是2020年,所以只插入2020的表
2020-01-07 16:40:28.165 DEBUG 7780 --- [pool-4-thread-1] c.o.p.p.m.S.insertSelective : ==> Preparing: INSERT INTO system_log ( type,pk_id,remark,user_name,created,action ) VALUES( ?,?,?,?,?,? )
2020-01-07 16:40:28.165 DEBUG 7780 --- [pool-4-thread-1] c.o.p.p.m.S.insertSelective : ==> Parameters: 1(Integer), 0(Integer), string(String), 15162191629(String), 2020-01-07 16:40:28.161(Timestamp), 内容(String)
2020-01-07 16:40:28.198 INFO 7780 --- [pool-4-thread-1] ShardingSphere-SQL : Rule Type: sharding
2020-01-07 16:40:28.198 INFO 7780 --- [pool-4-thread-1] ShardingSphere-SQL : Logic SQL: INSERT INTO system_log ( type,pk_id,remark,user_name,created,action ) VALUES( ?,?,?,?,?,? )
2020-01-07 16:40:28.198 INFO 7780 --- [pool-4-thread-1] ShardingSphere-SQL : SQLStatement: InsertStatement(super=DMLStatement(super=AbstractSQLStatement(type=DML, tables=Tables(tables=[Table(name=system_log, alias=Optional.absent())]), routeConditions=Conditions(orCondition=OrCondition(andConditions=[AndCondition(conditions=[Condition(column=Column(name=created, tableName=system_log), operator=EQUAL, compareOperator=null, positionValueMap={}, positionIndexMap={0=4})])])), encryptConditions=Conditions(orCondition=OrCondition(andConditions=[])), sqlTokens=[TableToken(tableName=system_log, quoteCharacter=NONE, schemaNameLength=0), SQLToken(startIndex=24)], parametersIndex=6, logicSQL=INSERT INTO system_log ( type,pk_id,remark,user_name,created,action ) VALUES( ?,?,?,?,?,? )), deleteStatement=false, updateTableAlias={}, updateColumnValues={}, whereStartIndex=0, whereStopIndex=0, whereParameterStartIndex=0, whereParameterEndIndex=0), columnNames=[type, pk_id, remark, user_name, created, action], values=[InsertValue(columnValues=[org.apache.shardingsphere.core.parse.old.parser.expression.SQLPlaceholderExpression@21625d01, org.apache.shardingsphere.core.parse.old.parser.expression.SQLPlaceholderExpression@34dda176, org.apache.shardingsphere.core.parse.old.parser.expression.SQLPlaceholderExpression@5d631384, org.apache.shardingsphere.core.parse.old.parser.expression.SQLPlaceholderExpression@13cfbf64, org.apache.shardingsphere.core.parse.old.parser.expression.SQLPlaceholderExpression@20f67249, org.apache.shardingsphere.core.parse.old.parser.expression.SQLPlaceholderExpression@79f9b130])])
2020-01-07 16:40:28.198 INFO 7780 --- [pool-4-thread-1] ShardingSphere-SQL : Actual SQL: ds0 ::: INSERT INTO system_log_2020 (type, pk_id, remark, user_name, created, action) VALUES (?, ?, ?, ?, ?, ?) ::: [1, 0, string, 15162191629, 2020-01-07 16:40:28.161, 内容]
2020-01-07 16:40:28.210 DEBUG 7780 --- [pool-4-thread-1] c.o.p.p.m.S.insertSelective : <== Updates: 1
  1. 如上的查询语句结果也同理,只查2020年

查询参数

{
"endTime": "2020-01-10 01:01:01",
"id": 435,
"page": 1,
"pageSize": 10,
"startTime": "2020-01-01 01:01:01"
}

查询结果

2020-01-07 16:50:49.878 DEBUG 5408 --- [nio-9000-exec-2] c.o.p.p.m.S.getReportLogList : ==> Preparing: SELECT created,user_name,`action`,id,remark FROM system_log WHERE pk_id=? and created BETWEEN ? and ? order by created desc LIMIT ?
2020-01-07 16:50:49.879 DEBUG 5408 --- [nio-9000-exec-2] c.o.p.p.m.S.getReportLogList : ==> Parameters: 435(Integer), 2020-01-01 01:01:01.0(Timestamp), 2020-01-10 01:01:01.0(Timestamp), 10(Integer)
2020-01-07 16:50:49.891 INFO 5408 --- [nio-9000-exec-2] ShardingSphere-SQL : Rule Type: sharding
2020-01-07 16:50:49.891 INFO 5408 --- [nio-9000-exec-2] ShardingSphere-SQL : Logic SQL: SELECT created,user_name,`action`,id,remark FROM system_log
WHERE pk_id=?
and created BETWEEN ? and ?
order by created desc LIMIT ?
2020-01-07 16:50:49.891 INFO 5408 --- [nio-9000-exec-2] ShardingSphere-SQL : SQLStatement: SelectStatement(super=DQLStatement(super=AbstractSQLStatement(type=DQL, tables=Tables(tables=[Table(name=system_log, alias=Optional.absent())]), routeConditions=Conditions(orCondition=OrCondition(andConditions=[AndCondition(conditions=[Condition(column=Column(name=created, tableName=system_log), operator=BETWEEN, compareOperator=null, positionValueMap={}, positionIndexMap={0=1, 1=2})])])), encryptConditions=Conditions(orCondition=OrCondition(andConditions=[])), sqlTokens=[TableToken(tableName=system_log, quoteCharacter=NONE, schemaNameLength=0)], parametersIndex=4, logicSQL=SELECT created,user_name,`action`,id,remark FROM system_log
WHERE pk_id=?
and created BETWEEN ? and ?
order by created desc LIMIT ? )), containStar=false, firstSelectItemStartIndex=7, selectListStopIndex=42, groupByLastIndex=0, items=[CommonSelectItem(expression=created, alias=Optional.absent()), CommonSelectItem(expression=user_name, alias=Optional.absent()), CommonSelectItem(expression=action, alias=Optional.absent()), CommonSelectItem(expression=id, alias=Optional.absent()), CommonSelectItem(expression=remark, alias=Optional.absent())], groupByItems=[], orderByItems=[OrderItem(owner=Optional.absent(), name=Optional.of(created), orderDirection=DESC, nullOrderDirection=ASC, index=-1, expression=null, alias=Optional.absent())], limit=Limit(offset=null, rowCount=LimitValue(value=-1, index=3, boundOpened=false)), subqueryStatement=null, subqueryStatements=[], subqueryConditions=[])
2020-01-07 16:50:49.891 INFO 5408 --- [nio-9000-exec-2] ShardingSphere-SQL : Actual SQL: ds0 ::: SELECT created,user_name,`action`,id,remark FROM system_log_2020
WHERE pk_id=?
and created BETWEEN ? and ?
order by created desc LIMIT ? ::: [435, 2020-01-01 01:01:01.0, 2020-01-10 01:01:01.0, 10]
2020-01-07 16:50:49.898 DEBUG 5408 --- [nio-9000-exec-2] c.o.p.p.m.S.getReportLogList : <== Total: 2

1.6. 总结

这次主要的碰壁内容就是created的大于小于问题,大于小于触发不了表分片行为,需要特别注意。希望对你有帮助
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https://www.cnblogs.com/sky-chen/p/12162587.html