Question

I have two tables each with 160k+ rows each. between the two some UUID are shared. I’m and using a foreach loop over the “new” table with an embedded foreach searching the “old” table. When a UUID match is out the “old” table is updated with data from the “new” table.

Both tables have an index on the ID.

My problem is this operation is extreme time intensive; does anyone know a more efficient way to do said search for matching UUIDs? Sidenote: we are using the MySQLi extension for PHP 5.3

Exp code:

$oldCounter = 0;
$newCounter = 1;
//loop
foreach( $accounts as $accKey=>$accValue )
{
echo( "New ID - " . $oldCounter++ . ": " . $accValue['id'] . "\n" );

foreach( $accountContactData as $acdKey=>$acdValue )
{
    echo( "Old ID - " $newCounter++ . ": " . $acdValue['id'] . "    \n" );

    if( $accValue['id'] == $acdValue['id'] && (
        $accValue['phone_office'] == "" || $accValue['phone_office'] == NULL || $accValue['phone_office'] == 0 )
    ){
        echo("ID match found\n");
        //when match found update accounts with accountsContact info
        $query = '
            UPDATE `accounts`
            SET
                `phone_fax` = "' . $acdValue['fax'] . '",
                `phone_office` = "' . $acdValue['telephone1'] . '",
                `phone_alternate` = "' . $acdValue['telephone2'] . '"
            WHERE
                `id` = "' . $acdValue['id'] . '"
        ';
        echo "" . $query . "\n\n";

        $DB->query($query);

        break 1;
    }

}
}
unset($oldCounter);
unset($newCounter);

Thank you in advance.

Answer 1

Do this all in SQL.

There is nothing that I see in your code that requires PHP.

UPDATE allows JOIN. JOIN the new and old tables and have your WHERE conditions match that of your description. Should be pretty straightforward and significantly faster.