PostgreSQL从另一个表更新一个表

Question

编辑：抱歉，我应该更好地解释一下，数据已从Salesforce中淘汰，从后端转储，ID字段为字母数字[例如。 00190000010PBdSAAX]，通常长度均为18，并且总是唯一的。 我将对数据类型进行一些更改，摆脱引号引起的标识符，并对索引进行一些更改，看看如何！

我正在使用PostgreSQL 9.5。 我正在将1个表更新为另一个表，两个表的结构相同，一个表具有[目标] 200万条记录，另一个表[源]大约70k，这基本上是对现有表执行更新，并使用唯一的表插入任何新记录要检查的ID。

它比我想象的要花费更长的时间，即使没有什么要更新并且只扫描记录，仍然有5分钟甚至更长的时间才能更新，无论有没有索引，都尝试将其中的2个字段加入其中略有不同的方式（仅使用WHERE和实际JOIN）。 只想知道是否有更好的方法来做，或者我做错了什么，只使用了Postgres几天。

我知道5分钟没什么大不了的（如果执行任何更新，则时间会更长），但是它与大约9个其他表的过程类似，这是中等大小的示例

两个表都如下所示[但仅具有不同的表名]

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
);

更新脚本如下

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，但这是杀了我

Answer 1

您的查询基本上是这样的：

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

我建议索引：

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

笔记：

• 我同意带引号的标识符不是一个好主意的意见。
• 您的表应具有某种主键。 名为id的列是不错的选择。
• 通常，与字符串相比， serial是主键更好的选择。