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# mysqldump --single-transaction: what is and when to use it

One of the options that mysqldump supports is --single-transaction flag. In this article, we will explain what this option does and when to use it.

# What is --single-transaction

The --single-transaction option allows mysqldump to backup a database using a single transaction. This means that the entire backup process will be executed within a single transaction, ensuring that the database remains in a consistent state throughout the backup.

# Why use --single-transaction

Using the --single-transaction option is recommended for databases that are frequently updated or have large amounts of data. This is because it ensures that the database remains in a consistent state throughout the backup, which is important if you need to restore the database later.

# Which engines have support for single transactions?

It's important to note that not all storage engines support transactions. If your database uses a storage engine that doesn't support transactions, using the --single-transaction option will not have any effect. Only the following MySQL engines have support for single transactions:

  • InnoDB
  • NDB

# How to use --single-transaction

The option can be used by passing the --single-transaction flag as in the example below:

mysqldump --single-transaction my_database > my_database.sql

# Using it together with --skip-lock-tables

Using the --single-transaction and --skip-lock-tables options together can provide several benefits:

  • consistent backup: the --single-transaction option ensures a consistent backup of your database by wrapping the entire mysqldump operation in a single transaction. This guarantees that the backup reflects a consistent state of your database at the time the transaction started
  • avoids locking tables: the --skip-lock-tables option avoids locking tables during the backup process, which can prevent downtime and disruption to active operations

Overall, using both options together provides a consistent, low-impact backup of your MySQL database, making it an ideal choice for environments where minimizing downtime and disruption is a priority.

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