Extensive MySQL Common Errors List

SimpleBackups founder

Laurent Lemaire

Co-founder, SimpleBackups

Last update on November 16, 2023
Originally posted on October 8, 2020

Errors or mistakes are common in any aspects, especially in development. Using MySQL or any database can't guarantee you an error-free environment.

In this article, we will discuss the structure or anatomy of MySQL errors and how to read them. We've also picked the top 10 most common MySQL errors and their description.

Table of Contents

The anatomy of MySQL errors

Each MySQL errors consists of the following parts that identify the error:

  • ERROR NUMBER is a unique number that identifies each error.
  • SQLSTATE is a code which identifies SQL error conditions.
  • ERROR MESSAGE describes the error in human readable format.

Here's an example MySQL error:

ERROR 1146 (42S02): Table 'test.no_such_table' doesn't exist

In this example above:

  • 1146 is the ERROR NUMBER
  • 42S02 is the SQLSTATE
  • Table 'test.no_such_table' doesn't exist is the ERROR MESSAGE

Access denied for user 'root'@'localhost' (using password: YES)

ERROR 1045: Access denied for user 'root'@'localhost'

This one is probably encountered at least once by anyone using MySQL.
This error can have many causes, such as wrong username and/or password, or lacks of permission to the database.

This error indicates that the MySQL server denied access to the 'root' user when attempting to connect from the 'localhost' server using the provided password.

💡To fix this, double-check the password and ensure that the user has the necessary privileges.
You can reset the password or grant the required permissions to resolve this issue.

Lost connection to MySQL server during query

ERROR 2013: Lost connection to MySQL server during query

This error happens when the connection between your MySQL client and database server times out.
Essentially, it took too long for the query to return data so the connection gets dropped.
This can occur due to various reasons, such as network issues or server timeouts.

💡 To resolve it, consider adjusting your MySQL server configuration to increase the connection timeout values or investigating network stability.

Too many connections

ERROR 1040: Too many connections

This error occurs when the MySQL server reaches its maximum allowed connections limit.

💡 To address this, you can either increase the max_connections setting in your MySQL configuration file or optimize your application to use fewer connections.

MySQL server has gone away

ERROR 2006 (HY000): MySQL server has gone away

This error indicates that the MySQL server terminated the connection unexpectedly.
It can happen due to various reasons, including long-running queries or server timeouts.

💡 To prevent it, you can adjust the wait_timeout and interactive_timeout settings in your MySQL configuration.

ERROR 2008: MySQL client ran out of memory

ERROR 2008: MySQL client ran out of memory

This error occurs when the MySQL client consumes more memory than available.

💡 To resolve it, you may need to optimize your queries, limit result sets, or allocate more memory to the MySQL client.

The table is full

ERROR 1114 (HY000): The table is full

If a table-full error occurs, it may be that the disk is full or that the table has reached its maximum size.
The effective maximum table size for MySQL databases is usually determined by operating system constraints on file sizes, not by MySQL internal limits.

💡 To address it, you can either:

  1. Increase the maximum allowed size for MEMORY table
    max_heap_table_size = 2G
    tmp_table_size = 2G
  2. Switch to the InnoDB storage engine
  3. Check disk space and increase available space:

You have an error in your SQL syntax

ERROR 1064 (42000): You have an error in your SQL syntax

This means that MySQL does not understand your query because of a syntax issue. Usually the cause of the issue is forgetting to enclose some literals or values in backticks or quotes. For example, instead of having the name of your database in a MySQL query as my-database it should be `my-database`.

The error message will even go further and pinpoint where the syntax start to be invalid, and you can use that as a starting point to hunt the issue.

💡 Carefully review your query and ensure that all SQL statements are correctly formatted and follow MySQL's syntax rules.

Packet too large

ERROR: Packet too large

When a MySQL client or the mysqld server gets a packet bigger than max_allowed_packet bytes, it issues a Packet too large error and closes the connection.

A 1 GB packet size is the largest possible packet size that can be transmitted to or from the MySQL server or client. The MySQL server or client issues an ER_NET_PACKET_TOO_LARGE error and closes the connection if it receives a packet bigger than max_allowed_packet bytes.

💡 You can resolve it by adjusting the max_allowed_packet setting in your MySQL configuration file.

Communication Errors and Aborted Connections

ERROR: Communication Errors and Aborted Connections

If you find errors like the following in your error log.

010301 14:38:23  Aborted connection 854 to db: 'users' user: 'simplebackups'

This means that something of the following has happened:

  • The client program did not call mysql_close() before exit.
  • The client had been sleeping more than wait_timeout or interactive_timeout without doing any requests.
  • The client program ended abruptly in the middle of the transfer.

Can’t create/write to file

ERROR: Can’t create/write to file

This error typically occurs when MySQL is unable to create or write to a file, often due to insufficient permissions or lack of disk space.
💡 Ensure that the MySQL user has the necessary file permissions, and check available disk space to resolve this issue.

Commands out of sync

ERROR: Commands out of sync

If you get this error in your client code, you are calling client functions in the wrong order.
For example, if you are using mysql_use_result() and try to execute a new query before you have called mysql_free_result().

💡 Ensure that your application follows the correct sequence of executing and fetching query results to avoid this error.

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