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
feifeigo12313 分钟前
升级到MySQL 8.4,MySQL启动报错:io_setup() failed with EAGAIN
数据库·mysql·adb
火龙谷2 小时前
【nosql】有哪些非关系型数据库?
数据库·nosql
焱焱枫3 小时前
Oracle获取执行计划之10046 技术详解
数据库·oracle
双力臂4043 小时前
MyBatis动态SQL进阶:复杂查询与性能优化实战
java·sql·性能优化·mybatis
qq_392397124 小时前
Redis常用操作
数据库·redis·wpf
A__tao5 小时前
一键将 SQL 转为 Java 实体类,全面支持 MySQL / PostgreSQL / Oracle!
java·sql·mysql
一只fish6 小时前
MySQL 8.0 OCP 1Z0-908 题目解析(17)
数据库·mysql
花好月圆春祺夏安6 小时前
基于odoo17的设计模式详解---装饰模式
数据库·python·设计模式
A__tao6 小时前
SQL 转 Java 实体类工具
java·数据库·sql
m0_653031366 小时前
腾讯云认证考试报名 - TDSQL数据库交付运维专家(TCCE PostgreSQL版)
运维·数据库·腾讯云