shortcode - Slow page Loads When Using Dynamic Coding

I have written code to get certain tags, and then show the products that have those tags.

This is the code:

$tag_string = '';

for ($i = 0; $i < 8; $i++) {
    for ($j = 0; $j < 8; $j++) {

        $tag_to_use = get_post_meta($post->ID, '_tag_to_use_'.$i.'_'.$j, true);
        $tag_string = $tag_to_use ? $tag_string .= $tag_to_use . ',' : $tag_string .= '';

    }
}

if ( substr( $tag_string, -1) == ',' ) {
    $tag_string = rtrim( $tag_string, ',' );
}

echo do_shortcode( '[products tag="' . $tag_string . '"]' );

}

When I run th code, I get slow page loads.

When I change this:

echo do_shortcode( '[products tag="' . $tag_string . '"]' );

To this:

echo do_shortcode( '[products tag="test,test1"]' );

The page loads fast.

Why is that happening, and how can I fix it? If any more information is needed, tell me and I'll update the question.

Thanks!

I have written code to get certain tags, and then show the products that have those tags.

This is the code:

$tag_string = '';

for ($i = 0; $i < 8; $i++) {
    for ($j = 0; $j < 8; $j++) {

        $tag_to_use = get_post_meta($post->ID, '_tag_to_use_'.$i.'_'.$j, true);
        $tag_string = $tag_to_use ? $tag_string .= $tag_to_use . ',' : $tag_string .= '';

    }
}

if ( substr( $tag_string, -1) == ',' ) {
    $tag_string = rtrim( $tag_string, ',' );
}

echo do_shortcode( '[products tag="' . $tag_string . '"]' );

}

When I run th code, I get slow page loads.

When I change this:

echo do_shortcode( '[products tag="' . $tag_string . '"]' );

To this:

echo do_shortcode( '[products tag="test,test1"]' );

The page loads fast.

Why is that happening, and how can I fix it? If any more information is needed, tell me and I'll update the question.

Thanks!

• shortcode
• performance

Share Improve this question edited Mar 20, 2019 at 18:26 SherylHohman 84199 silver badges1414 bronze badges asked Mar 19, 2019 at 7:33 OmerOmer 14911 gold badge44 silver badges1414 bronze badges 6

• What is the output of var_dump( $tag_string ); ? And instead of calling do_shortcode(), you could just directly call the function which handles the products shortcode. – Sally CJ Commented Mar 19, 2019 at 7:40
• This is the output of var_dump( $tag_string ); - string(22) "test,test1,test2,Aztec" . What is the function it calls? – Omer Commented Mar 19, 2019 at 7:45
• And is it still slow with echo do_shortcode( '[products tag="test,test1,test2,Aztec"]' ) ? – Sally CJ Commented Mar 19, 2019 at 7:52
• Yes. I have changed the shortcode to this: [products limit="8" paginate="true" tag="' . $tag_string . '"] and now it loads fine. Do you know how I could change it to infinte scroll instead of pagination? – Omer Commented Mar 19, 2019 at 7:56
• It's not that I don't know, but try searching for an existing question/answer/solution - or a plugin like this.. – Sally CJ Commented Mar 19, 2019 at 8:12

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1 Answer 1

Sorted by: Reset to default 1

I'm not sure, if it is the root of the problem, but the thing that I noticed is that your code ends up calling get_post_meta quite many times (64? 8 loops within 8 loops, yes?) for the same post.

Perhaps you could get all of the post meta just once, before the for loop. Then within your loop use isset() or ! empty() to check if the data exists.

Something along these lines,

$post_meta = get_post_meta($post->ID); // This returns an array with all the data in position 0, if I remember correctly
for ($i = 0; $i < 8; $i++) {
  for ($j = 0; $j < 8; $j++) {
    if ( isset( $post_meta[0]['_tag_to_use_'.$i.'_'.$j] ) ) {
      $tag_to_use = $post_meta[0]['_tag_to_use_'.$i.'_'.$j];
      // The meta value might be in a array with the position 0, var_dump $tag_to_use to see if this is the case
      // $tag_to_use = $post_meta[0]['_tag_to_use_'.$i.'_'.$j][0];
      $tag_string = $tag_to_use ? $tag_string .= $tag_to_use . ',' : $tag_string .= '';
    }
  }
}

Use var_dump to check that you get the array indexes correct and maybe_unserialize() the meta data, if needed.

I don't know if this is just broscience and wishful thinking, but maybe it's worth the try. You can of course use microtime to get a rough idea, if the loop above is faster than the original.