Export From 5.1 And Import To 5.5 Produce Different Values for Numeric Data Types (Doc ID 1588029.1)

Last updated on MARCH 08, 2017

Applies to:

MySQL Server - Version 5.5 and later
Information in this document applies to any platform.

Symptoms

On : 5.5 version, Installation and Upgrading

ACTUAL BEHAVIOR
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On upgrading from 5.1 to 5.5 version, the 5.1 approximate data type double stores as:

Old value = 4752.5578619999996590195

In the 5.5 version, the double stores as:

New value = 4752.5578620000000000000

EXPECTED BEHAVIOR
-----------------------
Expected behaviour would be for the 5.5 version to store identical to the 5.1 version as:

New value = 4752.5578619999996590195

STEPS
-----------------------
The issue can be reproduced at will with the following steps:
1. Create a table with type DOUBLE in 5.1
2. Upgrade to 5.5
3. Examine value in table.

BUSINESS IMPACT
-----------------------
The issue has the following business impact:
Due to this issue, users cannot get the same approximate values and hence may show difference in calculations using the data.

Changes

The 5.5 version includes a new dtoa library for converting strings to numerics.

Cause

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