Question

我的查询需要花费数小时才能运行，它在PgAdmin 4中的Postgres 9.3中超过9M行。由于它的格式，数据全部是字符串，我不得不使用子查询将其分成列。因此，为了使聚合视图变得更好，我投射了我需要的每个元素。因为有数百万行，所以有些数据元素在表中的某个点有空值，所以我需要where语句。我对where子句中的每个项目都有所不同。所有基本的btree索引。示例：在＆＃34; gnma2＆＃34;上创建索引loan_age_idx使用btree（＆＃34; Loan_Age＆＃34;）。由于强制转换函数而需要的where语句导致返回零行。我该怎么做才能删除那些但保留演员陈述？

    create table "t1" as    
Select  
gnma2."Issuer_ID",  
gnma2."As_of_Date",     
gnma2."Agency",     
gnma2."Loan_Purpose",   
gnma2."State",  
gnma2."Months_Delinquent",  
count(gnma2."Disclosure_Sequence_Number") as "Total_Loan_Count",    
avg(cast(gnma2."Loan_Interest_Rate" as double precision))/1000 as "avg_int_rate",   
avg(cast(gnma2."Original_Principal_Balance" as real))/100 as "avg_OUPB",    
avg(cast(gnma2."Unpaid_Principal_Balance" as real))/100 as "avg_UPB",   
avg(cast(gnma2."Loan_Age" as real)) as "avg_loan_age",  
avg(cast(gnma2."Loan_To_Value" as real))/100 as "avg_LTV",  
avg(cast(gnma2."Total_Debt_Expense_Ratio_Percent" as real))/100 as "avg_DTI",   
avg(cast(gnma2."Credit_Score" as real)) as "avg_credit_score",  
left(gnma2."First_Payment_Date",4) as "Origination_Yr"  
    From public."gnma2" 
    where 
    "Loan_Age" >= '1' and 
    "Loan_To_Value" >= '0' and 
    "Total_Debt_Expense_Ratio_Percent" >= '0' and 
    "Credit_Score" >= '0' and 
    "Loan_Interest_Rate" >= '0' and 
    "Original_Principal_Balance" >= '1' and 
    "Unpaid_Principal_Balance" >= '0'
Group By    
gnma2."Issuer_ID",  
gnma2."Agency",     
gnma2."Loan_Purpose",   
gnma2."State",  
gnma2."As_of_Date",     
gnma2."Months_Delinquent",  
gnma2."First_Payment_Date"; 

                                 QUERY PLAN                                                                                   

  HashAggregate  (cost=3496556.07..3496556.65 rows=13 width=91) (actual 
 time=124214.207..124214.207 rows=0 loops=1)
                            ->  Bitmap Heap Scan on gnma2  
 (cost=166750.75..3496546.65 rows=130 width=91) (actual time=124214.202..124214.20
2 rows=0 loops=1)
                                                                                        Recheck Cond: ("Loan_Age" >= '1'::bpchar)
                                                                                        Rows Removed by Index Recheck: 4785233
                                                                                        Filter: (("Loan_To_Value" >= '0'::bpchar) AND ("Total_Debt_Expense_Ratio_Percent" >= '0'::bpchar) AND ("Cr
edit_Score" >= '0'::bpchar) AND ("Loan_Interest_Rate" >= '0'::bpchar) AND ("Original_Principal_Balance" >= '1'::bpc
har) AND ("Unpaid_Principal_Balance" >= '0'::bpchar))
                                                                                        Rows Removed by Filter: 9311198
                                                                                        ->  Bitmap Index Scan on loan_age_indx  (cost=0.00..166750.72 rows=9029087 width=0) (actual time=5015.865.
.5015.865 rows=9311198 loops=1)
                                                                                                                                                    Index Cond: ("Loan_Age" >= '1'::bpchar)
        Total runtime: 124214.524 ms

查询问题 - Postgres / pgadmin4

0 个答案: