After Upgrading from 5.1 to 5.5 or 5.6 Data Appears Missing in Table Partitioned by KEY() and It is Possible to Insert a Duplicate Primary or Unique Keys for Those Rows or an Assertion May Happen

(Doc ID 1547727.1)

Last updated on MARCH 08, 2017

Applies to:

MySQL Server - Version 5.5 to 5.6 [Release 5.5 to 5.6]
Information in this document applies to any platform.


After upgrading from MySQL 5.1 to MySQL 5.5 or MySQL 5.6 the following symptoms may happen:

  1. Some data may appear to be missing for tables partitioning by KEY() on numeric, date and time, ENUM, and SET columns.
  2. For those tables in 1., it is possible to insert a row that violates a PRIMARY or UNIQUE KEY constraint.
  3. For InnoDB tables partitioned by KEY() an assertion is possible. See also Changes in MySQL 5.6.11.


The issue can be replicated using the following test.

In MySQL 5.1:


The server was upgraded from MySQL 5.1 to either MySQL 5.5 or 5.6 using an in-place upgrade instead of dumping the data and reloading.


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