Query vs. Batch_get_item

DynamoDB에서 item을 get하는 방식

1. query: partition key를 이용함
2. getitem: primary key (partition key + sort key)를 이용함

• 기존에 query를 사용했음 -> table에 5년 * 12달 = 60번의 query를 보내야 해서 api 요청 시간이 오래 걸림
• boto3 library의 batchgetitem을 사용하여 시간 단축 -> primary key 값들을 list에 넣어두어 for문 없이 한번에 item을 get할 수 있음
• batchgetitem 1회 요청 최대 row 개수는 100개
  -> 100개 이상의 요청을 보낼 경우 100개씩 나누어 여러 번 보내야함

import boto3
import json
from datetime import datetime
from boto3.dynamodb.conditions import Key, Attr
from decimal import Decimal
from multiprocessing import Manager, Process

dynamodb = boto3.resource("dynamodb", region_name = "ap-northeast-2")
table1 = dynamodb.Table("BUILDING_ENERGY_SIDO")
table2 = dynamodb.Table("BUILDINGENERGY_SIGUNGU")

def lambda_handler(event, context):
    Addr = event["params"]["querystring"]["addr"]
    Date=''
    year= datetime.today().year 
    month=datetime.today().month
    if(month<=3):
        month+=9
        year-=1
    else:
        month-=3
    if(month<10):
        month='0'+str(month)
    month=str(month)
    current_date=str(year)+str(month)
    response = table1.query(
                KeyConditionExpression = Key("date").eq(current_date)
                )
    while(response['Count']==0):
        if((int(current_date)-1)%100==0):
            current_date= str(int(current_date)-100+11)
        else:
            current_date = str(int(current_date)-1)
        response = table1.query(
                KeyConditionExpression = Key("date").eq(current_date)
                )
    Date=current_date
    
    #최근 5년
    intYear = (int(Date) // 100) * 100 #지금은 202200
    startyear = ((intYear // 100) - 5) * 100 #지금은 201700
    endyear = ((intYear // 100) - 1) * 100 #지금은 202100
    YEAR = []
    for x in range(5):
        for j in range(12):
            YEAR.append(str(startyear + (j + 1)))
        startyear = startyear + 100
    
    Addr_trunc = Addr[:5] + "00000"
    items_to_get = [0 for i in range(len(YEAR))]
    for i in range(len(YEAR)):
        item_dict = {"date":YEAR[i], "addr":Addr_trunc}
        items_to_get[i] = item_dict
    
    response = dynamodb.batch_get_item(
        RequestItems={
            "BUILDINGENERGY_SIGUNGU":{
                "Keys":items_to_get
            }
        }
        ) #순서는 random임

    response = response["Responses"]["BUILDINGENERGY_SIGUNGU"]
    ans= [0 for i in range(5)]
    x = 0
    for i in range(0, 60, 12):
        ans[x] = {"gas":0,"electricity":0,"gas_co2":0,"electricity_co2":0,"energy_sum":0,"co2_sum":0,"YEAR":YEAR[i][:4]}
        x = x + 1

    for i in range(len(YEAR)):
        yyy = response[i]["date"][:4]
        if yyy == YEAR[0][:4]:
            ans[0]["gas"] += response[i]["gas"]
            ans[0]["electricity"] += response[i]["electricity"]
            ans[0]["gas_co2"] += response[i]["gas_co2"]
            ans[0]["electricity_co2"] += response[i]["electricity_co2"]
            ans[0]["energy_sum"] += response[i]["energy_sum"]
            ans[0]["co2_sum"] += response[i]["co2_sum"]
        elif yyy == YEAR[12][:4]:
            ans[1]["gas"] += response[i]["gas"]
            ans[1]["electricity"] += response[i]["electricity"]
            ans[1]["gas_co2"] += response[i]["gas_co2"]
            ans[1]["electricity_co2"] += response[i]["electricity_co2"]
            ans[1]["energy_sum"] += response[i]["energy_sum"]
            ans[1]["co2_sum"] += response[i]["co2_sum"]
        elif yyy == YEAR[24][:4]:
            ans[2]["gas"] += response[i]["gas"]
            ans[2]["electricity"] += response[i]["electricity"]
            ans[2]["gas_co2"] += response[i]["gas_co2"]
            ans[2]["electricity_co2"] += response[i]["electricity_co2"]
            ans[2]["energy_sum"] += response[i]["energy_sum"]
            ans[2]["co2_sum"] += response[i]["co2_sum"]
        elif yyy == YEAR[36][:4]:
            ans[3]["gas"] += response[i]["gas"]
            ans[3]["electricity"] += response[i]["electricity"]
            ans[3]["gas_co2"] += response[i]["gas_co2"]
            ans[3]["electricity_co2"] += response[i]["electricity_co2"]
            ans[3]["energy_sum"] += response[i]["energy_sum"]
            ans[3]["co2_sum"] += response[i]["co2_sum"]
        else:
            ans[4]["gas"] += response[i]["gas"]
            ans[4]["electricity"] += response[i]["electricity"]
            ans[4]["gas_co2"] += response[i]["gas_co2"]
            ans[4]["electricity_co2"] += response[i]["electricity_co2"]
            ans[4]["energy_sum"] += response[i]["energy_sum"]
            ans[4]["co2_sum"] += response[i]["co2_sum"]
            
    return ans
    
    
    '''
    ans=[]
    
    sgas = 0; selectricity = 0; sgas_co2 = 0; selectricity_co2 = 0; senergy_sum = 0; sco2_sum = 0 #sum
    for i in range(len(YEAR)): #len(YEAR)가 60 -> query 60회 보내야함
        Addr_trunc = Addr[:5] + "00000"
        response = table2.query(
            KeyConditionExpression = Key("date").eq(YEAR[i]) & Key("addr").eq(Addr_trunc)
            )
        
        sgas += response['Items'][0]['gas']
        selectricity += response['Items'][0]['electricity']
        sgas_co2 += response['Items'][0]['gas_co2']
        selectricity_co2 += response['Items'][0]['electricity_co2']
        senergy_sum += response['Items'][0]['energy_sum']
        sco2_sum += response['Items'][0]['co2_sum']
        
        if (i+1) % 12 == 0:
            yyy = YEAR[i]
            item = {
                "gas":int(float(sgas) * 0.095),
                "electricity":selectricity,
                "gas_co2":sgas_co2,
                "electricity_co2":selectricity_co2,
                "energy_sum":senergy_sum,
                "co2_sum":sco2_sum,
                "YEAR":yyy[:4]
            }
            ans.append(item)
            sgas = 0; selectricity = 0; sgas_co2 = 0; selectricity_co2 = 0; senergy_sum = 0; sco2_sum = 0
        else:
            continue
    
    return ans
    '''