Query Size Limitations in MySQL INSERT Statements

When executing INSERT statements in MySQL, it's crucial to consider potential size limitations. This article explores the factors that determine the maximum number of rows and bytes that can be included in a single INSERT statement.

Row Count Limitation

MySQL does not enforce a limit on the number of rows that can be inserted using the "INSERT ... SELECT" pattern. This allows for the insertion of an infinitely large number of records, assuming the source data exists in other tables.

Size Limitation

However, when using the "INSERT ... VALUES" pattern to hard-code values, there is a limit imposed by the "max_allowed_packet" configuration variable. This variable sets the maximum allowed size of SQL statements sent from the client to the database server. The size limit applies to all types of queries, including INSERT statements.

To determine the appropriate value for "max_allowed_packet," consider the following factors:

• Available memory on the MySQL server
• Size of the data being inserted
• Number of rows being inserted

For most applications, a default value of 4MB is sufficient. However, if you encounter errors due to packet size limitations, you can increase the value as needed.

Therefore, while the number of rows that can be inserted using the "INSERT ... SELECT" pattern is effectively unlimited, the maximum size of an INSERT statement using the "INSERT ... VALUES" pattern is constrained by the "max_allowed_packet" configuration variable.