MariaDB Server Stuck on INSERT Query After Resume from Sleep - Causes and Solutions

1. MariaDB and Transactions: MariaDB uses transactions to ensure data consistency during writes. An INSERT query is part of a transaction.
2. Sleep and Disk Writes: When a computer goes to sleep, some data writes might be queued or delayed to save power.
3. Resume and Incomplete Transaction: When the computer resumes, MariaDB might be waiting for confirmation (like a disk write) for the INSERT query to complete the transaction.
4. Stuck INSERT: If the confirmation is stuck due to the sleep/resume cycle, the INSERT query appears frozen.

This can be frustrating because the database seems unresponsive. There are a few ways to address this:

• Changing MariaDB settings: Some configurations, like forcing data writes on every transaction commit, might interfere with the system's sleep behavior. However, this can have performance implications.
• Optimizing Sleep Settings: Some systems allow control over what data gets written to disk before sleep. This might help ensure MariaDB transactions are complete before sleep mode.

START TRANSACTION;  -- Begin the transaction

INSERT INTO your_table (data) VALUES ('This is some data');

-- Simulate waiting for disk write (could happen during sleep)
SELECT SLEEP(1);  -- Replace with actual logic that might stall

COMMIT;  -- This might get stuck if disk write is delayed

This code snippet starts a transaction, inserts some data, and then introduces a delay to simulate what might happen during sleep. In this scenario, the COMMIT operation waiting for the data to be written to disk could hang if the sleep/resume cycle disrupts that process.

Optimize System Sleep Settings:

• Some operating systems allow configuration of what data gets written to disk before entering sleep mode. This can help ensure MariaDB transactions are complete before sleep:

  • Windows: Search for "Change advanced power settings" in the Control Panel. You can then adjust settings related to hard disk write caching behavior.
  • Linux: The specific method depends on your distribution, but some involve editing files like /etc/systemd/sleep.conf.

Leverage Application Logic:

• If possible, consider modifying your application logic to handle potential sleep interruptions during inserts:

  • Batched Inserts: Instead of inserting data one row at a time, group multiple inserts into a single transaction. This can reduce the number of potential interruptions.
  • Retry Mechanism: Implement a retry mechanism within your application that can automatically attempt the INSERT query if it encounters an error during sleep resume.

Consider Alternatives:

• In some cases, depending on your specific needs, it might be preferable to keep the server running 24/7 to avoid sleep-related issues altogether. This might be suitable for dedicated servers or critical applications.