PostgreSQL從另一個表更新一個表

Question

編輯：抱歉，我應該更好地解釋一下，數據已從Salesforce中淘汰，從后端轉儲，ID字段為字母數字[例如。 00190000010PBdSAAX]，通常長度均為18，並且總是唯一的。 我將對數據類型進行一些更改，擺脫引號引起的標識符，並對索引進行一些更改，看看如何！

我正在使用PostgreSQL 9.5。 我正在將1個表更新為另一個表，兩個表的結構相同，一個表具有[目標] 200萬條記錄，另一個表[源]大約70k，這基本上是對現有表執行更新，並使用唯一的表插入任何新記錄要檢查的ID。

它比我想象的要花費更長的時間，即使沒有什么要更新並且只掃描記錄，仍然有5分鍾甚至更長的時間才能更新，無論有沒有索引，都嘗試將其中的2個字段加入其中略有不同的方式（僅使用WHERE和實際JOIN）。 只想知道是否有更好的方法來做，或者我做錯了什么，只使用了Postgres幾天。

我知道5分鍾沒什么大不了的（如果執行任何更新，則時間會更長），但是它與大約9個其他表的過程類似，這是中等大小的示例

兩個表都如下所示[但僅具有不同的表名]

CREATE TABLE public."Cases"
(
  "Past_Due__c" character varying(255),
  "Case_Age__c" character varying(255),
  "Next_Step_Due_Date__c" character varying(255),
  "Id" character varying(255),
  "AccountId" character varying(255),
  "Account_Number__c" character varying(255),
  "Account_Type__c" character varying(255),
  "CaseNumber" character varying(255),
  "CaseSubTypeDetail__c" character varying(255),
  "Case_Sub_Type__c" character varying(255),
  "Case_Type__c" character varying(255),
  "ClosedDate" character varying(255),
  "Collections_Step__c" character varying(255),
  "Customer_Number__c" character varying(255),
  "Next_Collections_Step__c" character varying(255),
  "Origin" character varying(255),
  "Priority" character varying(255),
  "Related_Complaint_Case__c" character varying(255),
  "Status__c" character varying(255),
  "Subject" text,
  "Type" character varying(255),
  "CreatedDate" character varying(255),
  "OwnerId" character varying(255),
  "ContactId" character varying(255),
  "Status" character varying(255),
  "Case_Comments__c" text,
  "Subscription__c" character varying(255),
  "Description" text,
  "Case_Outcome__c" text,
  "Case_Outcome_Reason__c" text,
  "Adjustment_Amount__c" character varying(255),
  "Product_Adjustment_Amount__c" character varying(255),
  "Product_Adjustment_Reason__c" character varying(255),
  "Service__c" character varying(255),
  "ParentId" character varying(255)
)
WITH (
  OIDS=FALSE
);

更新腳本如下

update public."cases" t2
set past_due__c = t1.past_due__c, case_age__c = t1.case_age__c, next_step_due_date__c = t1.next_step_due_date__c, accountid = t1.accountid, account_number__c = t1.account_number__c, account_type__c = t1.account_type__c, casesubtypedetail__c = t1.casesubtypedetail__c, case_sub_type__c = t1.case_sub_type__c, case_type__c = t1.case_type__c, closeddate = t1.closeddate, collections_step__c = t1.collections_step__c, customer_number__c = t1.customer_number__c, next_collections_step__c = t1.next_collections_step__c, origin = t1.origin, priority = t1.priority, related_complaint_case__c = t1.related_complaint_case__c, status__c = t1.status__c, subject = t1.subject, type = t1.type, ownerid = t1.ownerid, contactid = t1.contactid, status = t1.status, case_comments__c = t1.case_comments__c, subscription__c = t1.subscription__c, description = t1.description, case_outcome__c = t1.case_outcome__c, case_outcome_reason__c = t1.case_outcome_reason__c, adjustment_amount__c = t1.adjustment_amount__c, product_adjustment_amount__c = t1.product_adjustment_amount__c, product_adjustment_reason__c = t1.product_adjustment_reason__c, service__c = t1.service__c, parentid = t1.parentid, billing_account__c = t1.billing_account__c, billing_account_credit_balance__c = t1.billing_account_credit_balance__c, billing_address__c = t1.billing_address__c, lastmodifiedbyid = t1.lastmodifiedbyid, lastmodifieddate = t1.lastmodifieddate
from   public."temp_update_cases" t1
where  t1.id = t2.id

我想出的所有其他事情我都想通了，但這是殺了我

Answer 1

您的查詢基本上是這樣的：

update public."cases" t2
set  . . .
from   public."temp_update_cases" t1
where  t1.id = t2.id;

我建議索引：

create index idx_cases_id on public."cases"(id);
create index idx_temp_updte_cases_id on public."temp_update_cases"(id);

筆記：

• 我同意帶引號的標識符不是一個好主意的意見。
• 您的表應具有某種主鍵。 名為id的列是不錯的選擇。
• 通常，與字符串相比， serial是主鍵更好的選擇。