GaussDB(DWS)数据仓库：在云计算时代的技术进步之旅【绽放吧！GaussDB(DWS)云原生数仓】

sqlCopy code-- 创建性能统计表
CREATE TABLE performance_stats (
    query_id INT PRIMARY KEY,
    query_text TEXT,
    average_duration FLOAT
);
-- 定时收集性能统计信息
CREATE OR REPLACE FUNCTION collect_performance_stats() RETURNS TRIGGER AS $$
BEGIN
    -- 获取当前查询的信息
    SELECT INTO performance_stats
        pg_stat_get_backend_id(),
        pg_stat_get_backend_query(),
        pg_stat_get_backend_avg_duration()
    FROM pg_stat_get_backend_pid(TG_PID());
    
    -- 插入或更新性能统计表中的查询信息
    INSERT INTO performance_stats
    VALUES (performance_stats.query_id, performance_stats.query_text, performance_stats.average_duration)
    ON CONFLICT (query_id)
    DO UPDATE SET average_duration = excluded.average_duration;
    
    RETURN NULL;
END;
$$ LANGUAGE plpgsql;
-- 注册触发器，收集查询性能统计信息
CREATE TRIGGER collect_performance_stats_trigger
BEFORE STATEMENT
ON all
EXECUTE PROCEDURE collect_performance_stats();
-- 查询慢查询
SELECT query_id, query_text, average_duration
FROM performance_stats
WHERE average_duration > 100; -- 设置阈值，选择耗时较长的查询
-- 对慢查询进行优化
EXPLAIN ANALYZE <slow_query>; -- 分析查询计划，找到性能瓶颈
-- 对瓶颈进行适当调整

pythonCopy codeimport datetime
import os
# 配置数据库参数
db_host = "localhost"
db_port = 5432
db_name = "mydatabase"
db_user = "myuser"
db_password = "mypassword"
# 备份函数
def backup_database():
    # 获取当前时间作为备份文件名
    current_time = datetime.datetime.now().strftime("%Y%m%d%H%M%S")
    backup_file_name = f"backup_{current_time}.sql"
    # 构建备份命令
    backup_command = f"pg_dump -h {db_host} -p {db_port} -U {db_user} -Fc -f {backup_file_name} {db_name}"
    # 执行备份命令
    os.system(backup_command)
    print(f"Database backup successful. Backup file: {backup_file_name}")
# 清理函数
def cleanup_backups(days_to_keep):
    # 获取过期时间
    expiry_time = datetime.datetime.now() - datetime.timedelta(days=days_to_keep)
    # 获取当前目录下所有备份文件
    backup_files = os.listdir(".")
    
    for file in backup_files:
        # 判断文件是否为备份文件
        if file.startswith("backup_"):
            # 提取备份时间
            file_time_str = file.lstrip("backup_").rstrip(".sql")
            file_time = datetime.datetime.strptime(file_time_str, "%Y%m%d%H%M%S")
            
            # 如果备份时间早于过期时间，删除备份文件
            if file_time < expiry_time:
                os.remove(file)
                print(f"Deleted backup file: {file}")
# 备份数据库
backup_database()
# 清理过期备份文件（保留最近7天的备份文件）
cleanup_backups(days_to_keep=7)