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Description

This error indicates that a transaction attempting to acquire a lock on a database resource was forcefully terminated. This abortion occurs because another transaction requested an exclusive lock on the same resource, and the database system prioritized the exclusive lock. It commonly happens in environments with high concurrency and frequent data modifications to prevent deadlocks or ensure progress.

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Error Message

Wait on a lock was aborted due to a pending exclusive lock

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Known Causes

4 known causes

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High Database Concurrency

Too many concurrent transactions attempting to acquire locks on the same database resources can lead to contention and lock waits being aborted.

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Deadlock Resolution

The database system may abort a waiting transaction as part of its deadlock detection and resolution mechanism to prevent an infinite wait condition.

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Long-Running Transactions

Transactions that hold locks for an excessive duration can block other operations, leading to subsequent lock requests being aborted by the system.

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Inefficient Application Logic

Poorly designed queries or transaction sequences within the application can lead to excessive lock contention and subsequent abortions.

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Solutions

3 solutions available

1. Identify and Terminate Blocking Transactions medium

Find the transaction holding the lock and kill it.

1

Connect to your MariaDB server using a client like `mysql` or `mariadb`.

mariadb -u your_user -p

2

Show the current process list to identify long-running or blocking transactions. Look for transactions that are in a 'Locked' state or have been running for an unusually long time.

SHOW FULL PROCESSLIST;

3

Identify the `Id` of the transaction that is holding the lock. This is the transaction that is preventing other transactions from proceeding.

-- Example output: 12345 is the ID of the blocking transaction

4

If you are confident that the blocking transaction can be safely terminated, use the `KILL` command to abort it. Replace `12345` with the actual process ID.

KILL 12345;

5

Re-run the query that was previously failing to see if it can now proceed.

-- Re-run your original query here

2. Optimize Queries and Indexing advanced

Improve query performance to reduce lock duration.

1

Analyze the queries that are experiencing the lock wait. Use `EXPLAIN` to understand their execution plan.

EXPLAIN SELECT ... FROM your_table WHERE ...;

2

Identify any full table scans or inefficient joins. These can significantly increase the duration of locks.

-- Look for 'type: ALL' or missing index usage in EXPLAIN output

3

Add appropriate indexes to columns used in `WHERE`, `JOIN`, and `ORDER BY` clauses. This will help the database find data more quickly and reduce the time locks are held.

CREATE INDEX index_name ON your_table (column_name);

4

Rewrite queries to be more efficient. For example, avoid `SELECT *` if you only need a few columns, and ensure subqueries are optimized.

-- Example: Avoid SELECT * if only specific columns are needed

5

Consider breaking down large transactions into smaller, more manageable ones to minimize the time locks are held.

-- No direct code, but a strategic approach.

3. Adjust InnoDB Lock Wait Timeout medium

Configure the maximum time InnoDB will wait for a lock.

1

Connect to your MariaDB server.

mariadb -u your_user -p

2

Check the current value of `innodb_lock_wait_timeout`. This variable determines how long InnoDB will wait for a lock before aborting the transaction.

SHOW VARIABLES LIKE 'innodb_lock_wait_timeout';

3

If the current timeout is too short for your typical operations, you can increase it. Be cautious, as a very high timeout can lead to other performance issues if locks are truly stuck. A value between 10 and 60 seconds is often reasonable, but this depends on your workload. To set it temporarily for the current session:

SET SESSION innodb_lock_wait_timeout = 30; -- Set timeout to 30 seconds

4

To set it permanently, edit your MariaDB configuration file (e.g., `my.cnf` or `mariadb.cnf`) and add or modify the following line under the `[mysqld]` section. Then, restart the MariaDB service.

[mysqld]
innodb_lock_wait_timeout = 30

5

After changing the configuration, restart the MariaDB service for the changes to take effect.

sudo systemctl restart mariadb

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Related Errors

5 related errors

MariaDB Error 1689: Lock Wait Aborted