代码使用/ python慢​​慢解析大型xml文件

Question

我有2个非常大的xml文件，它们为同一个地方/建筑物/房间组合保存不同的数据。我目前在第一个大文件上使用python etree parse然后循环遍历它以提取地点/建筑物/房间ID（以及其他信息）然后使用这些id循环遍历第二个大型xml文件（与第一个相同的结构） ）我目前正在使用lxml iterparse来查找和提取与第一个文件中特定位置相关的第二个文件中的Place元素。然后它遍历那个place元素以找到相关的数据它工作，但它继续变得越来越慢，因为我进一步循环进入第一个文件。

我已经做了我能清除的所有内容（）在第二个大文件的iterparse中没有相关的元素，但是我有5000个位置可以循环，前100个处理非常快（少于一个分钟）然后接下来的400分钟需要30分钟，依此类推。 15个小时后，我在大约4000个设施，移动得非常慢。我怀疑解析其中一个文件的数据太多了。

这是使用通用化xml的简化代码（抱歉，我无法进一步简化）。

largefile1 = "largefile1.xml"
largefile2 = "largeFile2.xml"

ptree = ET.parse (largefile1)
proot = ptree.getroot()

o = open('output.txt', 'w')

def get_place_elem(pplaceid,largefile2):
    Placenode = ET.iterparse(Largefile2, events=("end",), tag='Place')

    for event, Place in Placenode:
        for PlaceId in Place.findall('PlaceIdentification'):
            placeid = PlaceId.find('PlaceIdentifier').text
                if placeid == pplaceid:
                    del Placenode
                    return Place
        Place.clear()
        while Place.getprevious() is not None:
            del Place.getparent()[0]
    del Placenode

def getfacdata(pplaceid,pbuildid,proomid,Place):

    for Build in Place.findall('Building'):
        euid = ' '
        for BuildId in Build.findall('BuildingIdentification'):
            bid = BuildId.find('Identifier').text
        if bid ==pbid:
            for Room in Build.findall('Room'):
                roomid = ' '
                for RoomId in Room.findall('RoomIdentification'):
                    roomid = RoomId.find('Identifier').text
                    if roomid == proomid:

                        ...Collect data from Room element...
                        ... do some simple math with if statements
                        return data; # list of 15 data values

for pPlace in proot.findall('.//Place'):
    for pPlaceId in pPlace.findall('PlaceIdentification'):
        pplaceid = pPlaceId.find('PlaceIdentifier').text
            if placeid == pplaceid:
                placecnt += 1
                #... get some data

    for pBuild in pPlace.findall('Buidling'):
        for pBuildId in pBuild.findall('BuildingIdentification'):
            pbid = pBuildId.find('Identifier').text

        for pRoom in pBuild.findall('Room'):
                for pRoomId in pRoom.findall('RoomIdentification'):
                    proomid = pRoom.find('Identifier').text

                    if prevpplaceid != pplaceid:
                        if placecnt != 1:Place.clear()
                            Place = get_fac_elem(pplaceid,largefile2)
                            prevpplaceid = pplaceid

                    data = getfacdata(pplaceid,pbid,proomid,Place)

                    #...Collect data from Room element...
                    #... do some simple math with if statements    
                    writer = csv.writer(o)
                    writer.writerow( ( # data from proom and from 'data' list from processing largefile2 in csv format##))
                    break    
    prevpplaceid = pplaceid


o.close()

genericified xml

 <Payload>
<Place>
    <PlaceName>Place1</PlaceName>
    <PlaceStatusCode>OP</PlaceStatusCode>
    <PlaceStatusCodeYear>2011</PlaceStatusCodeYear>
    <PlaceComment/>
    <PlaceIdentification>
        <PlaceIdentifier>id001</PlaceIdentifier>
        <StateAndCountyFIPSCode>77702</StateAndCountyFIPSCode>
    </PlaceIdentification>
    <PlaceAddress>
        <LocationAddressText>111 Main</LocationAddressText>
        <SupplementalLocationText/>
        <LocalityName>City1</LocalityName>
        <LocationAddressStateCode>State1</LocationAddressStateCode>
        <LocationAddressPostalCode>12345</LocationAddressPostalCode>
        <LocationAddressCountryCode>USA</LocationAddressCountryCode>
    </PlaceAddress>
    <PlaceGeographicCoordinates>
        <LatitudeMeasure>88.888</LatitudeMeasure>
        <LongitudeMeasure>-99.999</LongitudeMeasure>
    </PlaceGeographicCoordinates>
    <Building>
        <BuildingDescription>Building1</BuildingDescription>
        <BuildingTypeCode>999</BuildingTypeCode>
        <BuildingIdentification>
            <Identifier>Building1</Identifier>
        </BuildingIdentification>
        <Room>
            <RoomIdentification>
                <Identifier>Room1</Identifier>
            </RoomIdentification>
            ... More data ...
        </Room>
        <Room>
            <RoomIdentification>
                <Identifier>Room2</Identifier>
            </RoomIdentification>
            ... More data ...
        </Room>
        ...
    </Building>
    <Building>
        <BuildingDescription>Building2</BuildingDescription>
        <BuildingTypeCode>999</BuildingTypeCode>
        <BuildingIdentification>
            <Identifier>Building2</Identifier>
        </BuildingIdentification>
        <Room>
            <RoomIdentification>
                <Identifier>Room1</Identifier>
            </RoomIdentification>
            ... More data ...
        </Room>
        <Room>
            <RoomIdentification>
                <Identifier>Room4</Identifier>
            </RoomIdentification>
            ... More data ...
        </Room>
        ...
    </Building>
    ...
</Place>
<Place>
    ...
</Place>