为什么pymysql游标会增加内存？

Question

当我使用python 3.9和pymysql 1.1.0时，我发现从游标获取数据后内存会增加。我需要以循环方式运行模型。输入数据需要从 mysql 数据库下载。我使用 dbutils 来管理我的 pymysql 连接。然后我使用memory_profiler检查代码，发现当我使用“for row incursor:”时内存增加。我应该怎么做才能解决这个问题？谢谢！

    def databaseSelect(dataConnect,unit, kkspoint, kksname, starttime, endtimePlus):
        conn = dataConnect.connection()
        cursor = conn.cursor()  
        backdict = {}
        data1 = {}
        tables = []
        data = []
        unit = str(unit)
        kkspoint = str(kkspoint)
        kksname = str(kksname)
        starttime = str(starttime)
        endtimePlus = int(endtimePlus)
        starttime = datetime.datetime.strptime(starttime, "%Y-%m-%d %H:%M:%S")
        endtime = (starttime + datetime.timedelta(minutes=endtimePlus)).strftime('%Y-%m-%d %H:%M:%S')
        sql = 'show tables;'
        cursor.execute(sql)

        for row in cursor:
            # print('#' * 50 + "checkpoint5" + '#' * 50)
            # print(row)
            tables.append(str(row[0].decode('utf-8')))
            del row
        cursor = conn.close()
        conn.close()
        del (cursor,conn)
        findState = False
        for table in tables:
            a = table.split('y')[0].split('a')[2]
            if a == kkspoint:
                b = table.split('y')[1].split('m')[0]
                c = table.split('y')[1].split('m')[1].split('d')
                times = b + '-' + c[0] + '-' + c[1] + ' 00:00:00'
                originTime = datetime.datetime.strptime(times, '%Y-%m-%d %H:%M:%S')
                backdict.setdefault(a, []).append(originTime)
                del (a,b,c,times,originTime)
            del table
        for key in backdict.keys():
            backdict[key].sort()
            data1[key] = backdict[key]
            for i, timefind in enumerate(data1[key]):
                if starttime >= timefind and starttime < backdict[key][i + 1]:
                    checkTimeFind = timefind
                    findState = True
                    break
            if findState:
                break
            del key

        if unit == 'zj':
            kkspoint = 'Data' + kkspoint + 'y' + str(checkTimeFind.year) + 'm' + str(
                checkTimeFind.month) + 'd' + str(
                checkTimeFind.day)
        elif unit == 'fw':
            kkspoint = 'fwData' + kkspoint + 'y' + str(checkTimeFind.year) + 'm' + str(
                checkTimeFind.month) + 'd' + str(
                checkTimeFind.day)
        else:
            print('#' * 100 + '\nIPdownloader.databaseSelect\nwrong unit')
            raise IndexError

        sql = "select {} from {} where time between '{}' and '{}';".format(kksname, kkspoint, starttime, endtime)
        conn = dataConnect.connection()
        cursor = conn.cursor()  
        cursor.execute(sql)
        for row in cursor:
            data.append(row)
            del row
        cursor.close()
        conn.close()
        del (backdict, data1, sql, tables, cursor, conn, unit, kkspoint, kksname, starttime, endtime, findState)
        return data

Answer 1

我发现问题是 pandas 在 pymysql 返回数据后带来的。在我的代码中我使用的 pandas 版本是 2.1.0。它会在代码运行一次时留下一个weakref。这样记忆力就会增加。我将 pandas 版本更改为 1.5.3 后问题得到解决。现在看来还不错。