Why is My InnoDB INSERT Performance So Much Slower Than MyISAM?

Performance Issue with MySQL InnoDB Insert Operations

Introduction

Inserting data into MySQL tables using the InnoDB engine can, in certain scenarios, take significantly longer than expected. This article addresses this performance concern and provides a solution.

Key Question

Why is inserting data into MySQL InnoDB tables excessively slow?

Analysis

The provided test script illustrates a stark disparity in insertion performance between the MyISAM and InnoDB storage engines. MyISAM completes the insertion of 1 million rows in approximately 6 seconds, while InnoDB requires over 3400 seconds for the same task.

Explanation

The primary reason for this performance gap lies in the fundamental design differences between MyISAM and InnoDB. MyISAM lacks transaction support, allowing it to insert data more efficiently. In contrast, InnoDB enforces transaction integrity, requiring a commit operation after each statement. By default, InnoDB performs a log flush to disk after every insert, resulting in significant performance overhead.

Solution

To mitigate this performance issue, it is crucial to leverage InnoDB's transaction handling capabilities effectively. By enclosing the insert statements within an explicit transaction, we can reduce the frequency of disk writes and improve insertion speed dramatically.

To achieve this, execute the following statement before initiating the insert loop:

START TRANSACTION

After completing the insert operations, commit the transaction using the following statement:

COMMIT

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