聊聊shardingjdbc的ShardingMasterSlaveRouter

序

本文主要研究一下 sharding-jdbc 的 ShardingMasterSlaveRouter

ShardingMasterSlaveRouter

incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-route/src/main/java/org/apache/shardingsphere/core/route/router/masterslave/ShardingMasterSlaveRouter.java

@RequiredArgsConstructor
public final class ShardingMasterSlaveRouter {
    
    private final Collection<MasterSlaveRule> masterSlaveRules;
    
    /**
     * Route Master slave after sharding.
     * 
     * @param sqlRouteResult SQL route result
     * @return route result
     */
    public SQLRouteResult route(final SQLRouteResult sqlRouteResult) {for (MasterSlaveRule each : masterSlaveRules) {route(each, sqlRouteResult);
        }
        return sqlRouteResult;
    }
    
    private void route(final MasterSlaveRule masterSlaveRule, final SQLRouteResult sqlRouteResult) {Collection<TableUnit> toBeRemoved = new LinkedList<>();
        Collection<TableUnit> toBeAdded = new LinkedList<>();
        for (TableUnit each : sqlRouteResult.getRoutingResult().getTableUnits().getTableUnits()) {if (!masterSlaveRule.getName().equalsIgnoreCase(each.getDataSourceName())) {continue;}
            toBeRemoved.add(each);
            String actualDataSourceName;
            if (isMasterRoute(sqlRouteResult.getSqlStatement().getType())) {MasterVisitedManager.setMasterVisited();
                actualDataSourceName = masterSlaveRule.getMasterDataSourceName();} else {actualDataSourceName = masterSlaveRule.getLoadBalanceAlgorithm().getDataSource(masterSlaveRule.getName(), masterSlaveRule.getMasterDataSourceName(), new ArrayList<>(masterSlaveRule.getSlaveDataSourceNames()));
            }
            toBeAdded.add(createNewTableUnit(actualDataSourceName, each));
        }
        sqlRouteResult.getRoutingResult().getTableUnits().getTableUnits().removeAll(toBeRemoved);
        sqlRouteResult.getRoutingResult().getTableUnits().getTableUnits().addAll(toBeAdded);
    }
    
    private boolean isMasterRoute(final SQLType sqlType) {return SQLType.DQL != sqlType || MasterVisitedManager.isMasterVisited() || HintManager.isMasterRouteOnly();}
    
    private TableUnit createNewTableUnit(final String actualDataSourceName, final TableUnit originalTableUnit) {TableUnit result = new TableUnit(actualDataSourceName, originalTableUnit.getDataSourceName());
        result.getRoutingTables().addAll(originalTableUnit.getRoutingTables());
        return result;
    }
}

• ShardingMasterSlaveRouter 提供了 route 方法，返回 sqlRouteResult，这里修改了 sqlRouteResult 的 routingResult 的 tableUnits 的 TableUnit 集合

SQLRouteResult

incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-route/src/main/java/org/apache/shardingsphere/core/route/SQLRouteResult.java

@RequiredArgsConstructor
@Getter
@Setter
public final class SQLRouteResult {
    
    private final SQLStatement sqlStatement;
    
    private final GeneratedKey generatedKey;
    
    // For multiple thread read cached sqlStatement, clone limit on SQLRouteResult, because limit will be modified after cache
    // TODO need more good design here
    private Limit limit;
    
    private RoutingResult routingResult;
    
    private OptimizeResult optimizeResult;
    
    private final Collection<RouteUnit> routeUnits = new LinkedHashSet<>();
    
    public SQLRouteResult(final SQLStatement sqlStatement) {this(sqlStatement, null);
    }
}

• SQLRouteResult 拥有 RoutingResult 属性

RoutingResult

incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-route/src/main/java/org/apache/shardingsphere/core/route/type/RoutingResult.java

@Getter
public class RoutingResult {private final TableUnits tableUnits = new TableUnits();
    
    /**
     * Judge is route for single database and table only or not.
     *
     * @return is route for single database and table only or not
     */
    public boolean isSingleRouting() {return 1 == tableUnits.getTableUnits().size();}
}

• RoutingResult 拥有 TableUnits 属性

TableUnits

incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-route/src/main/java/org/apache/shardingsphere/core/route/type/TableUnits.java

@Getter
@ToString
public final class TableUnits {private final Collection<TableUnit> tableUnits = new LinkedHashSet<>();
    
    /**
     * Get all data source names.
     *
     * @return all data source names
     */
    public Collection<String> getDataSourceNames() {Collection<String> result = new HashSet<>(tableUnits.size(), 1);
        for (TableUnit each : tableUnits) {result.add(each.getDataSourceName());
        }
        return result;
    }
    
    /**
     * Get routing table via data source name and actual table name.
     *
     * @param dataSourceName data source name
     * @param actualTableName actual table name
     * @return routing table
     */
    public Optional<RoutingTable> getRoutingTable(final String dataSourceName, final String actualTableName) {for (TableUnit each : tableUnits) {Optional<RoutingTable> result = each.getRoutingTable(dataSourceName, actualTableName);
            if (result.isPresent()) {return result;}
        }
        return Optional.absent();}
    
    /**
     * Get actual tables group via data source name and logic tables' names.
     * <p>
     * Actual tables in same group are belong one logic name. 
     * </p>
     *
     * @param dataSourceName data source name
     * @param logicTableNames logic tables' names
     * @return actual tables group
     */
    public List<Set<String>> getActualTableNameGroups(final String dataSourceName, final Set<String> logicTableNames) {List<Set<String>> result = new ArrayList<>();
        for (String logicTableName : logicTableNames) {Set<String> actualTableNames = getActualTableNames(dataSourceName, logicTableName);
            if (!actualTableNames.isEmpty()) {result.add(actualTableNames);
            }
        }
        return result;
    }
    
    private Set<String> getActualTableNames(final String dataSourceName, final String logicTableName) {Set<String> result = new HashSet<>(tableUnits.size(), 1);
        for (TableUnit each : tableUnits) {result.addAll(each.getActualTableNames(dataSourceName, logicTableName));
        }
        return result;
    }
    
    /**
     * Get map relationship between data source and logic tables via data sources' names.
     *
     * @param dataSourceNames data sources' names
     * @return  map relationship between data source and logic tables
     */
    public Map<String, Set<String>> getDataSourceLogicTablesMap(final Collection<String> dataSourceNames) {Map<String, Set<String>> result = new HashMap<>();
        for (String each : dataSourceNames) {Set<String> logicTableNames = getLogicTableNames(each);
            if (!logicTableNames.isEmpty()) {result.put(each, logicTableNames);
            }
        }
        return result;
    }
    
    private Set<String> getLogicTableNames(final String dataSourceName) {Set<String> result = new HashSet<>(tableUnits.size(), 1);
        for (TableUnit each : tableUnits) {if (each.getDataSourceName().equalsIgnoreCase(dataSourceName)) {result.addAll(each.getLogicTableNames(dataSourceName));
            }
        }
        return result;
    }
}

• TableUnits 内部是 TableUnit 的集合

TableUnit

incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-route/src/main/java/org/apache/shardingsphere/core/route/type/TableUnit.java

@RequiredArgsConstructor
@Getter
@EqualsAndHashCode
@ToString
public final class TableUnit {
    
    private final String dataSourceName;
    
    private final String masterSlaveLogicDataSourceName;
    
    private final List<RoutingTable> routingTables = new LinkedList<>();
    
    public TableUnit(final String dataSourceName) {
        this.dataSourceName = dataSourceName;
        masterSlaveLogicDataSourceName = dataSourceName;
    }
    
    /**
     * Get routing table via data source name and actual table name.
     *
     * @param dataSourceName data source name
     * @param actualTableName actual table name
     * @return routing table
     */
    public Optional<RoutingTable> getRoutingTable(final String dataSourceName, final String actualTableName) {for (RoutingTable each : routingTables) {if (dataSourceName.equalsIgnoreCase(masterSlaveLogicDataSourceName) && each.getActualTableName().equalsIgnoreCase(actualTableName)) {return Optional.of(each);
            }
        }
        return Optional.absent();}
    
    /**
     * Get actual tables' names via data source name.
     *
     * @param dataSourceName data source name
     * @param logicTableName logic table name
     * @return  actual tables' names
     */
    public Set<String> getActualTableNames(final String dataSourceName, final String logicTableName) {Set<String> result = new HashSet<>(routingTables.size(), 1);
        for (RoutingTable each : routingTables) {if (dataSourceName.equalsIgnoreCase(this.dataSourceName) && each.getLogicTableName().equalsIgnoreCase(logicTableName)) {result.add(each.getActualTableName());
            }
        }
        return result;
    }
    
    /**
     * Get logic tables' names via data source name.
     *
     * @param dataSourceName data source name
     * @return  logic tables' names
     */
    public Set<String> getLogicTableNames(final String dataSourceName) {Set<String> result = new HashSet<>(routingTables.size(), 1);
        for (RoutingTable each : routingTables) {if (dataSourceName.equalsIgnoreCase(this.dataSourceName)) {result.add(each.getLogicTableName());
            }
        }
        return result;
    }
}

• TableUnit 包含了 RoutingTable 的集合

RoutingTable

incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-route/src/main/java/org/apache/shardingsphere/core/route/type/RoutingTable.java

@RequiredArgsConstructor
@Getter
@EqualsAndHashCode
@ToString
public final class RoutingTable {
    
    private final String logicTableName;
    
    private final String actualTableName;
}

• RoutingTable 包含了 logicTableName 与 actualTableName

小结

ShardingMasterSlaveRouter 提供了 route 方法，返回 sqlRouteResult，这里修改了 sqlRouteResult 的 routingResult 的 tableUnits 的 TableUnit 集合

doc

• ShardingMasterSlaveRouter