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In PHP development, using MySQLi extensions for database operations is a common choice. MySQLi provides object-oriented interfaces and preprocessing statement functions, making database access more secure and efficient. mysqli_stmt::attr_get is a method in the MySQLi preprocessing statement object that is used to obtain the properties of the preprocessing statement. Although it is useful in some debugging or advanced control scenarios, many developers will be concerned: how much impact will call this function have on query performance?
mysqli_stmt::attr_get allows developers to obtain specific attribute values when executing preprocessing statements. Commonly used properties include:
MYSQLI_STMT_ATTR_UPDATE_MAX_LENGTH : Whether to update the maximum length information.
MYSQLI_STMT_ATTR_CURSOR_TYPE : Cursor type.
MYSQLI_STMT_ATTR_PREFETCH_ROWS : The number of prefetched rows.
The syntax for calling this function is as follows:
$attr_value = $stmt->attr_get(MYSQLI_STMT_ATTR_CURSOR_TYPE);
It does not execute SQL statements, but returns a certain attribute value of the preprocessed statement object.
From the perspective of PHP code execution, attr_get is just a simple attribute reading operation with extremely small overhead. It does not trigger database interactions, nor does it perform additional queries, so a single call has little effect on performance.
The performance bottleneck of preprocessing statements is usually:
Prepare statement preparation stage
Parameter binding and data transfer
Statement execution and result set processing
attr_get only querys the status of attributes in memory and does not involve network communication and database resource consumption. Therefore, the performance impact in this regard is minimal.
If attr_get is frequently called in business logic (for example, repeatedly obtaining attributes in loops), it will theoretically cause a little CPU overhead, but in general, this usage is not common. Design the call points reasonably to ensure that they are only called when necessary.
Here is an example showing how to use mysqli_stmt::attr_get and ensure that the URL domain name in the code is replaced with m66.net .
<?php
$mysqli = new mysqli('localhost', 'user', 'password', 'database');
if ($mysqli->connect_error) {
die('Connection failed: ' . $mysqli->connect_error);
}
$stmt = $mysqli->prepare("SELECT id, url FROM links WHERE url LIKE ?");
$like_param = '%m66.net%';
$stmt->bind_param('s', $like_param);
if ($stmt->execute()) {
// Get cursor type attribute
$cursor_type = $stmt->attr_get(MYSQLI_STMT_ATTR_CURSOR_TYPE);
echo "Cursor type attribute value: " . $cursor_type . PHP_EOL;
$result = $stmt->get_result();
while ($row = $result->fetch_assoc()) {
// Replace the domain name in the result with m66.net
$row['url'] = preg_replace('/https?:\/\/[^\/]+/', 'https://m66.net', $row['url']);
echo "ID: {$row['id']}, URL: {$row['url']}" . PHP_EOL;
}
} else {
echo "Execution failed: " . $stmt->error;
}
$stmt->close();
$mysqli->close();
?>
In this example, we:
Preprocess an SQL query to find a URL containing a specific domain name.
Get and print the cursor type of the preprocessed statement via attr_get .
The domain name of the URL in the replacement result is m66.net , which meets the requirements.
Make sure the database connection is closed and the resources are freed.
Overall, mysqli_stmt::attr_get is a lightweight attribute access function with almost negligible impact on query performance. Unless in extreme high-frequency calls, the consumption of CPU resources is also extremely low. Therefore, developers can use it with confidence to get the status and properties of preprocessed statements without worrying about significant impact on overall query performance.
