Django 优化导出数据库：预回迁相关？

我想导出一个带有Django（3000行和100列）的数据库（15或20个表），但需要很长时间。 我认为解决方案是使用

预回迁相关的
，但我想听听你的意见，因为这对我来说非常复杂（这么多表…）。如果这就是解决方案，你能举几个不同模型的例子吗

def get_validated_acts(excl_fields_act_ids, excl_fields_act):

    qs=Act.objects.filter(validated=2)
    #list of acts
    acts=[]

    for act in qs.iterator():
        #list of fields for one act
        fields=[]
        act_ids=ActIds.objects.get(act=act, src="index")

        #ActIds
        for field in ActIds()._meta.fields:
            if field.name not in excl_fields_act_ids:
                fields.append(getattr(act_ids, field.name))

        #Act
        for field in Act()._meta.fields:
            if field.name not in excl_fields_act:
                #CodeSect and related
                if "code_sect_" in field.name:
                    temp=getattr(act, field.name)
                    if temp!=None:
                        fields.append(temp.code_sect)
                        fields.append(temp.code_agenda.code_agenda)
                    else:
                        fields.extend([None, None])
                #Rapporteurs (Person) and related (oeil) or Responsibles (Person) and related (prelex)
                elif "rapp_" in field.name or "resp_" in field.name:
                    temp=getattr(act, field.name)
                    if temp!=None:
                        fields.append(temp.name)
                        country=temp.country
                        party=temp.party
                        fields.append(country.country_code)
                        fields.append(party.party)
                        if "resp_" in field.name:
                            #party_family
                            fields.append(PartyFamily.objects.get(party=party, country=country).party_family)
                    else:
                        if "resp_" in field.name:
                            temp=[None]*4
                        else:
                            temp=[None]*3
                        fields.extend(temp)
                else:
                    #for all the other non fk fields, get its value
                    fields.append(getattr(act, field.name))

        #Act many to many fields
        for field in Act()._meta.many_to_many:
            #GvtCompo
            if "gvt_compo"==field.name:
                gvt_compos_country=gvt_compos_party=gvt_compos_party_family=""
                #for each country
                for gvt_compo in getattr(act, field.name).all():
                    country=gvt_compo.country
                    #for each party, add a "row" for each variable (country, party, party family)
                    for party in gvt_compo.party.all():
                        gvt_compos_country+=country.country_code+"; "
                        gvt_compos_party+=party.party+"; "
                        gvt_compos_party_family+=PartyFamily.objects.get(country=country, party=party).party_family+"; "
                #delete last "; "
                fields.append(gvt_compos_country[:-2])
                fields.append(gvt_compos_party[:-2])
                fields.append(gvt_compos_party_family[:-2])
            #adopt_cs_contre, adopt_cs_abs, adopt_pc_contre, adopt_pc_abs
            else:
                countries=""
                for country in getattr(act, field.name).all():
                    countries+=country.country_code+"; "
                fields.append(countries[:-2])

        #Ministers' attendance fields
        instances=MinAttend.objects.filter(act=act)
        temp_fields={"country": "", "verbatim": "", "status": ""}
        for instance in instances:
            temp_fields["country"]+=instance.country.country_code+"; "
            temp_fields["verbatim"]+=instance.verbatim.verbatim+"; "
            temp_fields["status"]+=Status.objects.get(verbatim=instance.verbatim, country=instance.country).status+"; "

        fields.append(temp_fields["country"][:-2])
        fields.append(temp_fields["verbatim"][:-2])
        fields.append(temp_fields["status"][:-2])

        acts.append(fields)

    return acts

如果有帮助，以下是主模型的一些字段
Act
：

class Act(models.Model):

    titre_en=models.CharField(max_length=1000, blank=True, null=True, default=None)
    code_sect_1=models.ForeignKey(CodeSect, related_name='code_sect_1', blank=True, null=True, default=None)
    code_sect_2=models.ForeignKey(CodeSect, related_name='code_sect_2', blank=True, null=True, default=None)
    code_sect_3=models.ForeignKey(CodeSect, related_name='code_sect_3', blank=True, null=True, default=None)
    code_sect_4=models.ForeignKey(CodeSect, related_name='code_sect_4', blank=True, null=True, default=None)
    rep_en_1=models.CharField(max_length=200, blank=True, null=True, default=None)
    rep_en_2=models.CharField(max_length=200, blank=True, null=True, default=None))
    type_acte=models.CharField(max_length=100, blank=True, null=True, default=None)
    com_amdt_tabled=models.IntegerField(max_length=3, blank=True, null=True, default=None)
    votes_agst_1=models.IntegerField(max_length=3, blank=True, null=True, default=None)
    rapp_1=models.ForeignKey(Person, related_name='rapp_1', blank=True, null=True, default=None)
    rapp_2=models.ForeignKey(Person, related_name='rapp_2', blank=True, null=True, default=None)
    rapp_3=models.ForeignKey(Person, related_name='rapp_3', blank=True, null=True, default=None)
    rapp_4=models.ForeignKey(Person, related_name='rapp_4', blank=True, null=True, default=None)
    adopt_propos_origine=models.DateField(max_length=10, blank=True, null=True, default=None)
    com_proc=models.CharField(max_length=100, blank=True, null=True, default=None)
    resp_1=models.ForeignKey(Person, related_name='resp_1', blank=True, null=True, default=None)
    resp_2=models.ForeignKey(Person, related_name='resp_2', blank=True, null=True, default=None)
    resp_3=models.ForeignKey(Person, related_name='resp_3', blank=True, null=True, default=None)
    transm_council=models.DateField(max_length=10, blank=True, null=True, default=None)
    adopt_cs_contre=models.ManyToManyField(Country, related_name='adopt_cs_contre')
    adopt_cs_abs=models.ManyToManyField(Country, related_name='adopt_cs_abs')
    adopt_pc_contre=models.ManyToManyField(Country, related_name='adopt_pc_contre')
    adopt_pc_abs=models.ManyToManyField(Country, related_name='adopt_pc_abs')
    gvt_compo=models.ManyToManyField(GvtCompo)

此代码似乎要快一点（快10%）：

我使用
prefetch\u related
并将所有对象存储在内存中。不确定这是不是一个好主意

def get_validated_acts(excl_fields_act_ids, excl_fields_act):
    tic=time.time()

    #querysets
    qs_act=Act.objects.defer("id",  'date_doc', "url_prelex", "validated", "validated_attendance").filter(validated=2).prefetch_related("gvt_compo", "adopt_cs_contre", "adopt_cs_abs", "adopt_pc_contre", "adopt_pc_abs").prefetch_related("gvt_compo__party")
    qs_actids=ActIds.objects.defer("id", 'src', "url_exists", 'act').filter(src="index")
    qs_cs=CodeSect.objects.all().prefetch_related("code_agenda", "config_cons")
    qs_pers=Person.objects.all()
    qs_party=Party.objects.all()
    qs_pf=PartyFamily.objects.all()
    qs_minattend=MinAttend.objects.all()
    qs_verb=Verbatim.objects.all()
    qs_status=Status.objects.all()

    #fields names
    names_actids=[field.name for field in ActIds()._meta.fields if field.name not in excl_fields_act_ids]
    names_act=[field.name for field in Act()._meta.fields if field.name not in excl_fields_act]
    names_act_m2m=[field.name for field in Act()._meta.many_to_many]

    #list of acts
    acts=[]

    for act in qs_act:
        #list of fields for one act
        fields=[]
        act_ids=qs_actids.get(act=act)

        #ActIds
        for field in names_actids:
            fields.append(getattr(act_ids, field))

        #Act
        for field in names_act:
            #CodeSect and related
            if "code_sect_" in field:
                cs_id=getattr(act, field+"_id")
                if cs_id!=None:
                    cs=qs_cs.get(pk=cs_id)
                    fields.append(cs.code_sect)
                    fields.append(cs.code_agenda.code_agenda)
                else:
                    fields.extend([None, None])
            #Rapporteurs (Person) and related (oeil) or Responsibles (Person) and related (prelex)
            elif "rapp_" in field or "resp_" in field:
                pers_id=getattr(act, field+"_id")
                if pers_id!=None:
                    pers=qs_pers.get(pk=pers_id)
                    party=qs_party.get(pk=pers.party_id)
                    fields.append(pers.name)
                    fields.append(pers.country_id)
                    fields.append(party.party)
                    if "resp_" in field:
                        #party_family
                        fields.append(qs_pf.get(party=party, country_id=pers.country_id).party_family)
                else:
                    if "resp_" in field:
                        temp=[None]*4
                    else:
                        temp=[None]*3
                    fields.extend(temp)
            else:
                #for all the other non fk fields, get its value
                fields.append(getattr(act, field))
#~ 
        #Act many to many fields
        for field in names_act_m2m:
            #GvtCompo
            if "gvt_compo"==field:
                gvt_compos_country=gvt_compos_party=gvt_compos_party_family=""
                #~ #for each country
                for gvt_compo in act.gvt_compo.all():
                    #for each party, add a "row" for each variable (country, party, party family)
                    for party in gvt_compo.party.all():
                        gvt_compos_country+=gvt_compo.country_id+"; "
                        gvt_compos_party+=party.party+"; "
                        gvt_compos_party_family+=qs_pf.get(party=party, country_id=gvt_compo.country_id).party_family+"; "
                #delete last "; "
                fields.append(gvt_compos_country[:-2])
                fields.append(gvt_compos_party[:-2])
                fields.append(gvt_compos_party_family[:-2])
            #~ #adopt_cs_contre, adopt_cs_abs, adopt_pc_contre, adopt_pc_abs
            else:
                countries=""
                for country in getattr(act, field).all():
                    countries+=country.country_code+"; "
                fields.append(countries[:-2])
#~ 
        #Ministers' attendance fields
        instances=qs_minattend.filter(act=act)
        temp_fields={"country": "", "verbatim": "", "status": ""}
        for instance in instances:
            temp_fields["country"]+=instance.country_id+"; "
            temp_fields["verbatim"]+=qs_verb.get(pk=instance.verbatim_id).verbatim+"; "
            temp_fields["status"]+=qs_status.get(verbatim_id=instance.verbatim_id, country_id=instance.country_id).status+"; "

        fields.append(temp_fields["country"][:-2])
        fields.append(temp_fields["verbatim"][:-2])
        fields.append(temp_fields["status"][:-2])

        acts.append(fields)

    tac=time.time()
    print "time", tac-tic

    return acts