MySQL InnoDB Transaction Data Loss Concern - Database Not Shutdown Properly

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1

I am creating a web application using PHP and MySQL, but I’m facing significant challenges with data integrity. The issue: My database frequently becomes corrupted, resulting in random data loss. Oddly, it is always parts of transactions that are lost, never the full transactions. Details about my setup: I’m utilizing WAMP on a Windows 7 machine to run this locally. It’s strictly for personal use and will not be available online. Below is an excerpt from my MySQL error log:

121109 10:09:56 InnoDB: Database was not shut down normally!
InnoDB: Starting crash recovery.
InnoDB: Reading tablespace information from the .ibd files...
InnoDB: Restoring possible half-written data pages from the doublewrite
InnoDB: buffer...
121109 10:09:58 InnoDB: Waiting for the background threads to start
121109 10:09:59 [Note] Crash recovery finished.

The PHP code I’m using includes the following structure:

<?php
$connection = mysqli_connect($host, $username, $password, $database);
mysqli_autocommit($connection, FALSE);

// Add user details
$addUserQuery = "INSERT INTO users (name, email) VALUES (?, ?)";
$stmt1 = mysqli_prepare($connection, $addUserQuery);
mysqli_stmt_bind_param($stmt1, "ss", $userName, $userEmail);
mysqli_stmt_execute($stmt1);

// Add related specifics
$addDetailsQuery = "INSERT INTO user_details (user_id, phone) VALUES (?, ?)";
$stmt2 = mysqli_prepare($connection, $addDetailsQuery);
mysqli_stmt_bind_param($stmt2, "is", $userId, $phoneNumber);
mysqli_stmt_execute($stmt2);

mysqli_commit($connection);
?>

Key points: I am uncertain whether this issue stems from my coding or MySQL settings. As I am relatively new to PHP programming, my code may not be very refined. The query that tends to experience data loss most often is the secondary INSERT statement.

2

You’re right to be concerned about data loss - that error log shows a real problem. The “database was not shutdown normally” message means MySQL is getting interrupted while writing data. This happens when WAMP services get killed suddenly or your system crashes unexpectedly. I’ve dealt with similar data integrity issues before. My antivirus was flagging MySQL operations and causing problems. Check your antivirus settings first - make sure it’s not scanning your WAMP folder. Next, look at your MySQL config. Set innodb_flush_log_at_trx_commit to 1 - this forces the log buffer to write to disk after each transaction commit, which makes your data much safer. Also add proper error handling to your PHP code after database statements. It’ll catch issues early and stop incomplete transactions from going through.