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.
Each MySQL errors consists of the following parts that identify the error:
Here's an example MySQL error:
ERROR 1146 (42S02): Table 'test.no_such_table' doesn't exist
In this example above:
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.
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.
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.
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
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.
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:
max_heap_table_size = 2G
tmp_table_size = 2G
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
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.
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.
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:
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.
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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