CODEWITHSUNDEEP
yiiyii2
yaser
yaser

Reputation: 120

Looping through a large number of database rows in Yii2

I'm using Yii2 and my database server is MySQL. I need to scan every row of a whole db table searching for occurrences of some text.

This is what I want but because of the large number of records, I'm not sure if I do it like this the server won't run out of memory or the MySQL server wont go away:

$rows = Posts::find()->select('content')->all();
foreach($rows as $post) {
    // do some regex on $post['content']. no need to save it back to the table.
}

It's a live server with a large database. I must do it on the fly, can't take down the server for back up and restore!

Would this work? Is there any better way to do this?

Upvotes: 0

Views: 3829

Answers (1)

drodata
drodata

Reputation: 527

The following two subsections of Accessing Data in Yii2 Guide have talked about your issue:

  • Retrieving Data in Arrays

    use yii\helpers\ArrayHelper;
$contents = ArrayHelper::getColumn(
  Post::find()->asArray()->all(),
  'content'
);
foreach ($contents as $content) {

}

  • Retrieving Data in Batches

    // fetch 10 rows at a time
foreach(Posts::find()->select('content')->each(10) as $post) {
    // ...
}

Both methods could reduce memory cost.

Upvotes: 7

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