preamble
Apache ShardingSphere is a
distributed database ecosystem that transforms any database into a distributed database and enhances it with capabilities such as data sharding, elastic scaling, encryption, and more.
Apache ShardingSphere is designed with the philosophy of Database Plus to build a standard and ecosystem for the upper layers of heterogeneous databases. It focuses on how to fully utilize the computational and storage power of databases, rather than implementing a completely new database. It takes a view of the upper layers of databases and focuses more on collaboration between them than on the database itself.
1、ShardingSphere-JDBC
ShardingSphere-JDBC is positioned as a lightweight Java framework with additional services provided at the JDBC layer of Java.
1.1 Application Scenarios
Apache ShardingSphere-JDBC can be configured in Java and YAML in two ways , developers can choose the appropriate configuration according to the scenario .
- Database Read/Write Separation
- Database Tables and Databases
1.2, Principle
- Sharding-JDBC routing results are determined by the sharding field and sharding method, if the query condition has an id field the case is good, the query will fall to a specific sharding
- If you query a field that is not sliced, you will query all the db’s or tables and let the result set be encapsulated to the client.
1.3. spring boot integration
1.3.1 Adding dependencies
<! -- Split Table Split Library Dependencies -->
<dependency>
<groupId>org.apache.shardingsphere</groupId>
<artifactId>sharding-jdbc-spring-boot-starter</artifactId>
<version>4.1.1</version>
</dependency>
1.3.2, Additive placement
spring:
main:
# One entity class corresponds to multiple tables, overriding the
allow-bean-definition-overriding: true
shardingsphere:
datasource:
ds0:
# Configure data source specifics, including connection pools, drivers, addresses, usernames and passwords
driver-class-name: com.mysql.cj.jdbc.Driver
jdbc-url: jdbc:mysql://127.0.0.1:3306/account?autoReconnect=true&allowMultiQueries=true
password: root
type: com.zaxxer.hikari.HikariDataSource
username: root
ds1:
driver-class-name: com.mysql.cj.jdbc.Driver
jdbc-url: jdbc:mysql://127.0.0.1:3306/account?autoReconnect=true&allowMultiQueries=true
password: root
type: com.zaxxer.hikari.HikariDataSource
username: root
# Configure the data source, give the data source a name
names: ds0,ds1
props:
sql:
show: true
sharding:
tables:
user_info:
# Specify the user_info table distribution, configure which database the table is in, and what the table names are.
actual-data-nodes: ds0.user_info_${0..9}
database-strategy:
standard:
preciseAlgorithmClassName: com.xxxx.store.account.config.PreciseDBShardingAlgorithm
rangeAlgorithmClassName: com.xxxx.store.account.config.RangeDBShardingAlgorithm
sharding-column: id
table-strategy:
standard:
preciseAlgorithmClassName: com.xxxx.store.account.config.PreciseTablesShardingAlgorithm
rangeAlgorithmClassName: com.xxxx.store.account.config.RangeTablesShardingAlgorithm
sharding-column: id
1.3.3. Development of slicing algorithms
1.3.3.1, Precision library algorithm
/**
* :: Precise pooling algorithms
*/
public class PreciseDBShardingAlgorithm implements PreciseShardingAlgorithm<Long> {
/**
*
* @param availableTargetNames Configure the list of all the
* @param preciseShardingValue Fragment value
* @return
*/
@Override
public String doSharding(Collection<String> availableTargetNames, PreciseShardingValue<Long> preciseShardingValue) {
Long value = preciseShardingValue.getValue();
//Suffix 0, 1
String postfix = String.valueOf(value % 2);
for (String availableTargetName : availableTargetNames) {
if(availableTargetName.endsWith(postfix)){
return availableTargetName;
}
}
throw new UnsupportedOperationException();
}
}
1.3.3.2. Range-splitting algorithm
/**
* :: Range-splitting algorithm
*/
public class RangeDBShardingAlgorithm implements RangeShardingAlgorithm<Long> {
@Override
public Collection<String> doSharding(Collection<String> collection, RangeShardingValue<Long> rangeShardingValue) {
return collection;
}
}
1.3.3.3, Precise table-splitting algorithm
/**
* :: Precise tabulation algorithm
*/
public class PreciseTablesShardingAlgorithm implements PreciseShardingAlgorithm<Long> {
/**
*
* @param availableTargetNames Configure the list of all the
* @param preciseShardingValue Fragment value
* @return
*/
@Override
public String doSharding(Collection<String> availableTargetNames, PreciseShardingValue<Long> preciseShardingValue) {
Long value = preciseShardingValue.getValue();
// Suffix
String postfix = String.valueOf(value % 10);
for (String availableTargetName : availableTargetNames) {
if(availableTargetName.endsWith(postfix)){
return availableTargetName;
}
}
throw new UnsupportedOperationException();
}
}
1.3.3.4. Scope sub-tabulation algorithm
/**
* :: Range-splitting table algorithm
*/
public class RangeTablesShardingAlgorithm implements RangeShardingAlgorithm<Long> {
@Override
public Collection<String> doSharding(Collection<String> collection, RangeShardingValue<Long> rangeShardingValue) {
Collection<String> result = new ArrayList<>();
Range<Long> valueRange = rangeShardingValue.getValueRange();
Long start = valueRange.lowerEndpoint();
Long end = valueRange.upperEndpoint();
Long min = start % 10;
Long max = end % 10;
for (Long i = min; i < max +1; i++) {
Long finalI = i;
collection.forEach(e -> {
if(e.endsWith(String.valueOf(finalI))){
result.add(e);
}
});
}
return result;
}
}
1.3.4 Database table construction
DROP TABLE IF EXISTS `user_info_0`;
CREATE TABLE `user_info_0` (
`id` bigint(20) NOT NULL,
`account` varchar(255) DEFAULT NULL,
`user_name` varchar(255) DEFAULT NULL,
`pwd` varchar(255) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
1.3.5, Business applications
1.3.5.1 Defining entity classes
@Data
@TableName(value = "user_info")
public class UserInfo {
/**
* :: Primary key
*/
private Long id;
/**
* :: Account number
*/
private String account;
/**
* :: User name
*/
private String userName;
/**
* Password
*/
private String pwd;
}
1.3.5.2. Defining interfaces
public interface UserInfoService{
/**
* :: Preservation
* @param userInfo
* @return
*/
public UserInfo saveUserInfo(UserInfo userInfo);
public UserInfo getUserInfoById(Long id);
public List<UserInfo> listUserInfo();
}
1.3.5.3. Implementation classes
@Service
public class UserInfoServiceImpl extends ServiceImpl<UserInfoMapper, UserInfo> implements UserInfoService {
@Override
@Transactional
public UserInfo saveUserInfo(UserInfo userInfo) {
userInfo.setId(IdUtils.getId());
this.save(userInfo);
return userInfo;
}
@Override
public UserInfo getUserInfoById(Long id) {
return this.getById(id);
}
@Override
public List<UserInfo> listUserInfo() {
QueryWrapper<UserInfo> userInfoQueryWrapper = new QueryWrapper<>();
userInfoQueryWrapper.between("id",1623695688380448768L,1623695688380448769L);
return this.list(userInfoQueryWrapper);
}
}
1.3.6 Generating IDs – Snowflake Algorithm
package com.xxxx.tore.common.utils;
import cn.hutool.core.lang.Snowflake;
import cn.hutool.core.util.IdUtil;
/**
* :: Generation of various component IDs
*/
public class IdUtils {
/**
* :: Snowflake algorithm
* @return
*/
public static long getId(){
Snowflake snowflake = IdUtil.getSnowflake(0, 0);
long id = snowflake.nextId();
return id;
}
}
1.4, seata yielding sharding-jdbc consistent
https://github.com/seata/seata-samples/tree/master/springcloud-seata-sharding-jdbc-mybatis-plus-samples
1.4.1 Add dependencies in common
<! --seata dependencies -->
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-seata</artifactId>
<version>2021.0.4.0</version>
</dependency>
<! -- sharding-jdbc integrates seata distributed transactions -->
<dependency>
<groupId>org.apache.shardingsphere</groupId>
<artifactId>sharding-transaction-base-seata-at</artifactId>
<version>4.1.1</version>
</dependency>
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
<version>2021.0.4.0</version>
<exclusions>
<exclusion>
<groupId>com.alibaba.nacos</groupId>
<artifactId>nacos-client</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>com.alibaba.nacos</groupId>
<artifactId>nacos-client</artifactId>
<version>1.4.2</version>
</dependency>
1.4.2 Modification of the account-service service
@Service
public class AccountServiceImpl extends ServiceImpl<AccountMapper, Account> implements AccountService {
@Autowired
private OrderService orderService;
@Autowired
private StorageService storageService;
/**
* :: Storage of commodity codes and their corresponding prices
*/
private static Map<String,Integer> map = new HashMap<>();
static {
map.put("c001",3);
map.put("c002",5);
map.put("c003",10);
map.put("c004",6);
}
@Override
@Transactional
@ShardingTransactionType(TransactionType.BASE)
public void debit(OrderDTO orderDTO) {
//Deduction of account balances
int calculate = this.calculate(orderDTO.getCommodityCode(), orderDTO.getCount());
AccountDTO accountDTO = new AccountDTO(orderDTO.getUserId(), calculate);
QueryWrapper<Account> objectQueryWrapper = new QueryWrapper<>();
objectQueryWrapper.eq("id",1);
objectQueryWrapper.eq(accountDTO.getUserId() != null,"user_id",accountDTO.getUserId());
Account account = this.getOne(objectQueryWrapper);
account.setMoney(account.getMoney() - accountDTO.getMoney());
this.saveOrUpdate(account);
//Deductions from inventory
this.storageService.deduct(new StorageDTO(null,orderDTO.getCommodityCode(),orderDTO.getCount()));
// Generate orders
this.orderService.create(orderDTO);
}
/**
* :: Calculation of the total price of goods purchased
* @param commodityCode
* @param orderCount
* @return
*/
private int calculate(String commodityCode, int orderCount){
//Commodity prices
Integer price = map.get(commodityCode) == null ? 0 : map.get(commodityCode);
return price * orderCount;
}
}
Note: The logic of the transfer order generation call is modified, Reduce Balance -> Reduce Inventory -> Generate Order. The call entry method note is added:
@ShardingTransactionType(TransactionType.BASE)
1.4.3 Modifying the business-service service
@Service
public class BusinessServiceImpl implements BusinessService {
@Autowired
private OrderService orderService;
@Autowired
private StorageService storageService;
@Autowired
private AccountService accountService;
@Override
public void purchase(OrderDTO orderDTO) {
//Deduct money from account
accountService.debit(orderDTO);
}
}
1.4.4 Modifying the order-service service
@Service
public class OrderServiceImpl extends ServiceImpl<OrderMapper,Order> implements OrderService {
/**
* :: Storage of commodity codes and their corresponding prices
*/
private static Map<String,Integer> map = new HashMap<>();
static {
map.put("c001",3);
map.put("c002",5);
map.put("c003",10);
map.put("c004",6);
}
@Override
@Transactional
@ShardingTransactionType(TransactionType.BASE)
public Order create(String userId, String commodityCode, int orderCount) {
int orderMoney = calculate(commodityCode, orderCount);
Order order = new Order();
order.setUserId(userId);
order.setCommodityCode(commodityCode);
order.setCount(orderCount);
order.setMoney(orderMoney);
//Save the order
this.save(order);
try {
TimeUnit.SECONDS.sleep(30);
} catch (InterruptedException e) {
e.printStackTrace();
}
if(true){
throw new RuntimeException(" rollback test ");
}
return order;
}
/**
* :: Calculation of the total price of goods purchased
* @param commodityCode
* @param orderCount
* @return
*/
private int calculate(String commodityCode, int orderCount){
//Commodity prices
Integer price = map.get(commodityCode) == null ? 0 : map.get(commodityCode);
return price * orderCount;
}
}
1.4.5 Configuration file reference
server:
port: 8090
spring:
main:
# One entity class corresponds to multiple tables, overriding the
allow-bean-definition-overriding: true
shardingsphere:
datasource:
ds0:
# Configure data source specifics, including connection pools, drivers, addresses, usernames and passwords
driver-class-name: com.mysql.cj.jdbc.Driver
jdbc-url: jdbc:mysql://127.0.0.1:3306/account?autoReconnect=true&allowMultiQueries=true
password: root
type: com.zaxxer.hikari.HikariDataSource
username: root
ds1:
driver-class-name: com.mysql.cj.jdbc.Driver
jdbc-url: jdbc:mysql://127.0.0.1:3306/account?autoReconnect=true&allowMultiQueries=true
password: root
type: com.zaxxer.hikari.HikariDataSource
username: root
# Configure the data source, give the data source a name
names: ds0,ds1
props:
sql:
show: true
sharding:
tables:
account_tbl:
actual-data-nodes: ds0.account_tbl_${0..1}
database-strategy:
standard:
preciseAlgorithmClassName: com.xxxx.store.account.config.PreciseDBExtShardingAlgorithm
#rangeAlgorithmClassName: com.xxxx.store.account.config.RangeDBShardingAlgorithm
sharding-column: id
table-strategy:
standard:
preciseAlgorithmClassName: com.xxxx.store.account.config.PreciseTablesExtShardingAlgorithm
#rangeAlgorithmClassName: com.xxxx.store.account.config.RangeTablesShardingAlgorithm
sharding-column: id
user_info:
# Specify the user_info table distribution, configure which database the table is in, and what the table names are.
actual-data-nodes: ds0.user_info_${0..9}
database-strategy:
standard:
preciseAlgorithmClassName: com.xxxx.store.account.config.PreciseDBShardingAlgorithm
rangeAlgorithmClassName: com.xxxx.store.account.config.RangeDBShardingAlgorithm
sharding-column: id
table-strategy:
standard:
preciseAlgorithmClassName: com.xxxx.store.account.config.PreciseTablesShardingAlgorithm
rangeAlgorithmClassName: com.xxxx.store.account.config.RangeTablesShardingAlgorithm
sharding-column: id
# Above is the sharding-jdbc configuration
cloud:
nacos:
discovery:
server-addr: localhost:8848
namespace: 1ff3782d-b62d-402f-8bc4-ebcf40254d0a
application:
name: account-service # Name of the microservice
# datasource:
# username: root
# password: root
# url: jdbc:mysql://127.0.0.1:3306/account
# driver-class-name: com.mysql.cj.jdbc.Driver
seata:
enabled: true
enable-auto-data-source-proxy: false
application-id: account-service
tx-service-group: default_tx_group
service:
vgroup-mapping:
default_tx_group: default
disable-global-transaction: false
registry:
type: nacos
nacos:
application: seata-server
server-addr: 127.0.0.1:8848
namespace: 1ff3782d-b62d-402f-8bc4-ebcf40254d0a
group: SEATA_GROUP
username: nacos
password: nacos
config:
nacos:
server-addr: 127.0.0.1:8848
namespace: 1ff3782d-b62d-402f-8bc4-ebcf40254d0a
group: SEATA_GROUP
username: nacos
password: nacos
