SQL load direct path load index 无效的原因

Index (unique) state changing to unusable status after data loading using SQL*Loader. The steps below are executed to load the data:

1/ disable constraint--如果不是单独建的index, 对应index会drop掉的

2/ load data using SQL*Loader

3/ remove duplicate records

4/ enable constraint

The execution of step 3 fails due to an index in unusable state:

\n removing duplicate records from the table ... \n

DELETE FROM <TABLE_NAME1> WHERE rowid not in (SELECT MIN(rowid) FROM <TABLE_NAME1> GROUP BY <COLUMN_NAME>)---rowid在期间不能有table move 操作

*

ERROR at line 1:

ORA-01502: index '<INDEX_NAME>_PK' or partition of such index is

in unusable state

Checking the available indexes and their status from dba_indexes, we have:

|-------------------|------------|----------|-----------------|
| INDEX_NAME | INDEX_TYPE | STATUS | TABLE_NAME |
| <INDEX_NAME>_PK | NORMAL | UNUSABLE | <TABLE_NAME1> |
| <INDEX_NAME>_PK | NORMAL | VALID | <TABLE_NAME2> |

CHANGES

CAUSE

Some integrity constraints are automatically disabled During a direct path load. The constraints that remain enabled during a direct path load are:

  • NOT NULL
  • UNIQUE
  • PRIMARY KEY (unique-constraints on not-null columns)--PK自动not null

这么说不就是外键 check disable了

  • NOT NULL constraints are checked at column array build time. Any row that violates the NOT NULL constraint is rejected.

Even though UNIQUE constraints remain enabled during direct path loads, any row that violates those constraints is loaded anyway (this is different than in conventional path in which such rows would be rejected).

When indexes are rebuilt at the end of the direct path load, UNIQUE constraints are verified and if a violation is detected, then the index will be left in an unusable state.

不拒绝

Indexes Left in an Unusable State


SQL*Loader leaves indexes in an Index Unusable state when the data segment being loaded becomes more up-to-date than the index segments that index it.

Any SQL statement that tries to use an index that is in an Index Unusable state returns an error. The following conditions cause a direct path load to leave an index or a partition of a partitioned index in an Index Unusable state:

  • SQL*Loader runs out of space for the index and cannot update the index.

  • The data is not in the order specified by the SORTED INDEXES clause.

  • There is an instance failure, or the Oracle shadow process fails while building the index.

  • There are duplicate keys in a unique index.

  • Data savepoints are being used, and the load fails or is terminated by a keyboard interrupt after a data savepoint occurred.

Hence this is a expected behavior as:

  • Some duplicate rows are getting loaded and indexes are going to unusable state when unique indexes are used.

  • Or -

  • SQL*Loader leaves indexes in an Index Unusable state when the data segment being loaded becomes more up-to-date than the index segments that index it.

SOLUTION

To overcome the issue:

  • In few cases using conventional path load has resolved the issue.
  • Or -
  • Using normal index instead of unique index will not affect the index status.
  • 先建立普通index 加unique key 控制
  • Or -
  • One can follow below workaround for unique indexes.

  • 本来是个死局,重复的删不了,index不能rebuild,只有drop,

    • Drop the offending index and load the data.
    • Detect duplicate rows
    • Remove the duplicate rows and recreate the index.
相关推荐
古月居GYH2 小时前
【数据分析】如何在PyCharm中高效配置和使用SQL
ide·sql·pycharm
计算机毕设定制辅导-无忧学长6 小时前
西门子 PLC 与 Modbus 集成:S7-1500 RTU/TCP 配置指南(一)
服务器·数据库·tcp/ip
程序员柳7 小时前
基于微信小程序的校园二手交易平台、微信小程序校园二手商城源代码+数据库+使用说明,layui+微信小程序+Spring Boot
数据库·微信小程序·layui
梦在深巷、7 小时前
MySQL/MariaDB数据库主从复制之基于二进制日志的方式
linux·数据库·mysql·mariadb
IT乌鸦坐飞机7 小时前
ansible部署数据库服务随机启动并创建用户和设置用户有完全权限
数据库·ansible·centos7
IT_10247 小时前
Spring Boot项目开发实战销售管理系统——数据库设计!
java·开发语言·数据库·spring boot·后端·oracle
祁思妙想8 小时前
八股学习(三)---MySQL
数据库·学习·mysql
惊骇世俗王某人9 小时前
1.MySQL之如何定位慢查询
数据库·mysql
程序员张39 小时前
SQL分析与打印-p6spy组件
spring boot·sql·mybatis·mybatisplus·p6spy
秦歌6669 小时前
向量数据库-Milvus快速入门
数据库·milvus