C++与Hive、Spark、libhdfs、ACID交互技巧
C++与Hive交互的实例
以下是C++与Hive交互的实例代码片段，涵盖连接、查询、数据操作等常见场景。假设使用libhdfs或thrift接口实现，部分示例需要结合Hive环境配置。
基础连接与查询
示例1：通过Thrift连接HiveServer2
#include <transport/TSocket.h>
#include <protocol/TBinaryProtocol.h>
#include <service/HiveClient.h>using namespace apache::thrift;
using namespace apache::hive::service;std::shared_ptr<TTransport> socket(new TSocket("localhost", 10000));
std::shared_ptr<TTransport> transport(new TBufferedTransport(socket));
std::shared_ptr<TProtocol> protocol(new TBinaryProtocol(transport));
HiveClient client(protocol);transport->open();
client.execute("SHOW DATABASES");
transport->close();
示例2：执行简单查询并获取结果
std::vector<std::string> results;
client.fetchAll(results); // 假设已实现结果集遍历
for (const auto& row : results) {std::cout << row << std::endl;
}
数据操作
示例3：创建表
client.execute("CREATE TABLE users (id INT, name STRING)");
示例4：插入数据
client.execute("INSERT INTO users VALUES (1, 'Alice'), (2, 'Bob')");
示例5：批量插入（通过文件加载）
client.execute("LOAD DATA LOCAL INPATH '/path/to/data.csv' INTO TABLE users");
示例6：更新数据（需Hive支持ACID）
client.execute("UPDATE users SET name='Charlie' WHERE id=2");
示例7：删除数据
client.execute("DELETE FROM users WHERE id=1");
查询操作
示例8：条件查询
client.execute("SELECT * FROM users WHERE id > 1");
示例9：聚合查询
client.execute("SELECT COUNT(*), AVG(age) FROM employee");
示例10：JOIN操作
client.execute("SELECT a.*, b.department FROM employees a JOIN dept b ON a.dept_id = b.id");
示例11：子查询
client.execute("SELECT * FROM (SELECT id, name FROM users) tmp WHERE id < 100");
示例12：分区查询
client.execute("SELECT * FROM logs WHERE dt='2023-10-01'");
表操作
示例13：查看表结构
client.execute("DESCRIBE FORMATTED users");
示例14：添加列
client.execute("ALTER TABLE users ADD COLUMNS (age INT)");
示例15：重命名表
client.execute("ALTER TABLE users RENAME TO customers");
示例16：删除表
client.execute("DROP TABLE IF EXISTS users");
高级功能
示例17：使用UDF
client.execute("CREATE TEMPORARY FUNCTION my_udf AS 'com.example.MyUDF'");
client.execute("SELECT my_udf(name) FROM users");
示例18：窗口函数
client.execute("SELECT name, salary, RANK() OVER (PARTITION BY dept ORDER BY salary DESC) FROM employees");
示例19：动态分区插入
client.execute("SET hive.exec.dynamic.partition.mode=nonstrict");
client.execute("INSERT INTO TABLE logs PARTITION(dt) SELECT id, content, dt FROM source");
示例20：事务操作（Hive 3+）
client.execute("START TRANSACTION");
client.execute("INSERT INTO t1 VALUES (1)");
client.execute("COMMIT");
性能优化
示例21：设置并行度
client.execute("SET mapreduce.job.reduces=10");
示例22：使用Tez引擎
client.execute("SET hive.execution.engine=tez");
示例23：启用压缩
client.execute("SET hive.exec.compress.output=true");
示例24：使用桶表查询
client.execute("SELECT * FROM bucketed_users TABLESAMPLE(BUCKET 1 OUT OF 4)");
示例25：EXPLAIN分析
client.execute("EXPLAIN SELECT * FROM users WHERE id > 100");
注意事项
- 需确保HiveServer2服务已启动
- 部分功能依赖Hive版本（如ACID需Hive 3+）
- 实际开发中建议使用连接池管理Thrift连接
- 错误处理代码未完整展示，需自行添加异常捕获
使用C++实现ACID特性与Hive 3+交互的实例
以下是通过C++与Hive 3+交互实现ACID特性的实例，涵盖事务操作、数据一致性及性能优化。
连接Hive并创建ACID表
#include <sql.h>
#include <sqlext.h>
#include <iostream>void createAcidTable() {SQLHENV env;SQLHDBC dbc;SQLHSTMT stmt;SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &env);SQLSetEnvAttr(env, SQL_ATTR_ODBC_VERSION, (void*)SQL_OV_ODBC3, 0);SQLAllocHandle(SQL_HANDLE_DBC, env, &dbc);SQLDriverConnect(dbc, NULL, (SQLCHAR*)"DSN=HiveDSN;", SQL_NTS, NULL, 0, NULL, SQL_DRIVER_COMPLETE);SQLAllocHandle(SQL_HANDLE_STMT, dbc, &stmt);SQLExecDirect(stmt, (SQLCHAR*)"CREATE TABLE acid_table (id INT, name STRING) STORED AS ORC TBLPROPERTIES ('transactional'='true')", SQL_NTS);SQLFreeHandle(SQL_HANDLE_STMT, stmt);SQLDisconnect(dbc);SQLFreeHandle(SQL_HANDLE_DBC, dbc);SQLFreeHandle(SQL_HANDLE_ENV, env);
}
开启事务并插入数据
void transactionalInsert() {SQLHSTMT stmt;SQLExecDirect(stmt, (SQLCHAR*)"START TRANSACTION", SQL_NTS);SQLExecDirect(stmt, (SQLCHAR*)"INSERT INTO acid_table VALUES (1, 'Alice')", SQL_NTS);SQLExecDirect(stmt, (SQLCHAR*)"COMMIT", SQL_NTS);
}
原子性操作示例
void atomicOperation() {try {SQLExecDirect(stmt, (SQLCHAR*)"START TRANSACTION", SQL_NTS);SQLExecDirect(stmt, (SQLCHAR*)"INSERT INTO acid_table VALUES (2, 'Bob')", SQL_NTS);throw std::runtime_error("Simulated failure");SQLExecDirect(stmt, (SQLCHAR*)"COMMIT", SQL_NTS);} catch (...) {SQLExecDirect(stmt, (SQLCHAR*)"ROLLBACK", SQL_NTS);}
}
批量插入优化
void batchInsert() {SQLExecDirect(stmt, (SQLCHAR*)"START TRANSACTION", SQL_NTS);for (int i = 0; i < 1000; ++i) {std::string query = "INSERT INTO acid_table VALUES (" + std::to_string(i) + ", 'User" + std::to_string(i) + "')";SQLExecDirect(stmt, (SQLCHAR*)query.c_str(), SQL_NTS);}SQLExecDirect(stmt, (SQLCHAR*)"COMMIT", SQL_NTS);
}
使用预编译语句
void preparedStatement() {SQLHSTMT stmt;SQLPrepare(stmt, (SQLCHAR*)"INSERT INTO acid_table VALUES (?, ?)", SQL_NTS);int id = 3;std::string name = "Charlie";S