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
骑着王八撵玉兔1 小时前
【性能优化与架构调优(二)】高性能数据库设计与优化
数据库·性能优化·架构
想要入门的程序猿2 小时前
Qt写入excel
数据库·qt·excel
Q_970956392 小时前
java+vue+SpringBoo校园失物招领网站(程序+数据库+报告+部署教程+答辩指导)
java·数据库·vue.js
Wyc724092 小时前
Maven
java·数据库·maven
程序猿小D3 小时前
[附源码+数据库+毕业论文]基于Spring+MyBatis+MySQL+Maven+jsp实现的电影小说网站管理系统,推荐!
java·数据库·mysql·spring·毕业设计·ssm框架·电影小说网站
羊小猪~~3 小时前
数据库学习笔记(十七)--触发器的使用
数据库·人工智能·后端·sql·深度学习·mysql·考研
背太阳的牧羊人3 小时前
Neo4j 的向量搜索(Neo4jVector)和常见的向量数据库(比如 Milvus、Qdrant)之间的区别与联系
数据库·neo4j·milvus
liulun4 小时前
在浏览器中使用SQLite(官方sqlite3.wasm)
数据库·sqlite·wasm
IT项目管理5 小时前
达梦数据库DMHS介绍及安装部署
linux·数据库
你都会上树?5 小时前
MySQL MVCC 详解
数据库·mysql