Undefined Variables in db.php

I just came across this, specifically the line 685 issue.

I updated my configuration function to explicitly include the value for the write parameter even though I’m using the default and that seemed to fix the issue for me.

@tchsup Here’s an example of explicitly defining the read and write values even though they are the defaults:

$wpdb->add_database(array(
	'host'     => DB_HOST,     // If port is other than 3306, use host:port.
	'user'     => DB_USER,
	'password' => DB_PASSWORD,
	'name'     => DB_NAME,
	'read'     => 1,
	'write'    => 1
));

@deepakdcc I’m currently using HyperDB on a site running 5.7.2. Could you share the critical error you’re getting?

it shows a critical error, here is my configuration but I have no idea how to make partitioning work on a round-robin basis for multiple databases. can you help me with this?
for example, i run a multisite network with version 5.7.2, and have 100+ databases and want to partitions the datas like when a new blog is created it should automatically sit in a database and the next blog in the next database and so on . or any suggestions for better performance since in run woocommerce in it which is resource-intensive

$wpdb->add_database(array(
‘host’ => ‘localhost’,
‘user’ => ‘new user’,
‘password’ => ‘password’,
‘name’ => ‘new database’,
));
$wpdb->add_database(array(
‘host’ => ‘localhost’,
‘user’ => ‘newuser’,
‘password’ => ‘password’,
‘name’ => ‘new database’,
‘dataset’ => ‘set1’,
));
$wpdb->add_callback(‘my_db_callback’);
function my_db_callback($query, $wpdb) {
// Multisite blog tables are “{$base_prefix}{$blog_id}_*”
if ( preg_match(“/^{$wpdb->base_prefix}\d+_/i”, $wpdb->table) )
return ‘set1’;
}
*/

@tp22 hi, i wrote you in mail for this, please let me know if you can help me in this , i can pay for this