SHOW READWRITE_SPLITTING RULES 如何过滤字段-Go服务器开发

在 ShardingSphere-Proxy 中，SHOW READWRITE_SPLITTING RULES 命令本身不支持直接的字段过滤，但可以通过以下几种方式实现类似效果：

1. 使用系统视图查询（推荐）

-- 查询读写分离规则的基本信息
SELECT rule_name, write_data_source_name 
FROM information_schema.readwrite_splitting_rules;

-- 查询特定规则的详细配置
SELECT * FROM information_schema.readwrite_splitting_rules 
WHERE rule_name = 'your_rule_name';

-- 只显示规则名称和读写数据源
SELECT rule_name, write_data_source_name, read_data_source_names
FROM information_schema.readwrite_splitting_rules;

2. 使用 FORMAT 参数结合外部处理

-- JSON格式输出后使用jq工具过滤（Linux/Mac）
SHOW READWRITE_SPLITTING RULES FORMAT JSON | jq '.rules[].name'

-- YAML格式输出后使用yq工具过滤
SHOW READWRITE_SPLITTING RULES FORMAT YAML | yq '.rules[].name'

3. MySQL客户端字段过滤

-- 使用\G垂直显示（适合查看单个规则）
SHOW READWRITE_SPLITTING RULES LIKE '%rule_name%'\G

-- 使用LIMIT限制返回行数
SHOW READWRITE_SPLITTING RULES LIMIT 1;

📊 information_schema 视图可用字段

DESC information_schema.readwrite_splitting_rules;

-- 常见字段包括：
-- rule_name                 规则名称
-- write_data_source_name    写数据源名称  
-- read_data_source_names    读数据源名称列表
-- load_balancer_type        负载均衡器类型
-- load_balancer_props       负载均衡器属性
-- algorithm_type            算法类型
-- algorithm_props           算法属性

🔧 实用查询示例

查看所有规则名称

SELECT rule_name FROM information_schema.readwrite_splitting_rules;

查看特定规则的写数据源

SELECT rule_name, write_data_source_name 
FROM information_schema.readwrite_splitting_rules 
WHERE rule_name = 'ds_0_rw_rule';

查看负载均衡器配置

SELECT rule_name, load_balancer_type, load_balancer_props
FROM information_schema.readwrite_splitting_rules;

查看读数据源列表

SELECT rule_name, read_data_source_names
FROM information_schema.readwrite_splitting_rules;

💡 Shell脚本自动化处理

#!/bin/bash

# 提取所有规则名称
mysql -h127.0.0.1 -P3307 -uroot -p -e \
"SELECT rule_name FROM information_schema.readwrite_splitting_rules" \
-N -B | tr '\n' ','

# 提取特定规则的写数据源  
RULE_NAME="ds_0_rw_rule"
mysql -h127.0.0.1 -P3307 -uroot -p -e \
"SELECT write_data_source_name FROM information_schema.readwrite_splitting_rules WHERE rule_name='$RULE_NAME'" \
-N -B

🛠️ Python程序化处理示例

import pymysql

def get_readwrite_rules(filter_fields=None):
    connection = pymysql.connect(host='127.0.0.1',
                                port=3307,
                                user='root',
                                password='password',
                                database='sharding_db')
    
    try:
        with connection.cursor() as cursor:
            if filter_fields:
                fields = ', '.join(filter_fields)
                sql = f"SELECT {fields} FROM information_schema.readwrite_splitting_rules"
            else:
                sql = "SHOW READWRITE_SPLITTING RULES"
            
            cursor.execute(sql)
            return cursor.fetchall()
    finally:
        connection.close()

# 只获取规则名称和写数据源
rules = get_readwrite_rules(['rule_name', 'write_data_source_name'])
for rule in rules:
    print(f"Rule: {rule[0]}, Write DS: {rule[1]}")

总结建议：