PHP foreach code performance speed - php

Question

I am trying to optimize increase the speed of this loop. I would like it if anyone has any ideas to boost the speed as there is thousands of members and it does take time time to complete currently
SQL Stored PROCEDURE MembersMobileByVenue returns this->
Example
FirstName Phone Venue
Aaron 04******* 7272CD46D51F
Brad 04******* CF105BB0
Adam 04******* 7272CD46D51F
Craig 04******* CF105BB0
PHP
$venueIDS = isset($_POST['location']) ? $_POST['location'] : array();
$msg = $_POST['message'];
$response = array();
if(!empty($venueIDS)){
$Members = GoldCardMembers::MembersMobileByVenue();
foreach($Members as $Member){
if(in_array($Member->Venue, $venueIDS)){
$destination = $Member->Phone;
$text = 'Hi ' . $Member->FirstName . ' ' .$msg. '. Reply STOP to opt out';
$ref = 'Members';
$content = '&to='.rawurlencode($destination).
'&message='.rawurlencode($text).
'&ref='.rawurlencode($ref);
$smsbroadcast_response = sendSMS($content);
$response_lines = explode("\n", $smsbroadcast_response);
foreach( $response_lines as $data_line){
$message_data = "";
$message_data = explode(':',$data_line);
if($message_data[0] == "OK"){
array_push($response, "The message to ".$message_data[1]." was successful, with reference ".$message_data[2]."\n");
}elseif( $message_data[0] == "BAD" ){
array_push($response, "The message to ".$message_data[1]." was NOT successful. Reason: ".$message_data[2]."\n");
}elseif( $message_data[0] == "ERROR" ){
array_push($response, "There was an error with this request. Reason: ".$message_data[1]."\n");
}
}
}
}
}
foreach($response as $message){
echo $message;
}

Answer 1

$venueIDS = isset($_POST['location']) ? $_POST['location'] : array();
$msg = $_POST['message'];
$text = "";
$destination = "";
$content = "";
$response_lines = array();
$smsbroadcast_response = "";
$message_data = array();
if(!empty($venueIDS)){
$Members = GoldCardMembers::MembersMobileByVenue();
foreach($Members as $Member){ // O(n) size of $Members
if(in_array($Member->Venue, $venueIDS)){ // O(v) size of $venueIDs
$destination = rawurlencode($Member->Phone);
$text = rawurlencode($Member->FirstName . ' ' .$msg);
$content = '&to='. $destination .
'&message=Hi ' . $text . '. Reply STOP to opt out'.
'&ref=Members';
$smsbroadcast_response = sendSMS($content);
$response_lines = explode("\n", $smsbroadcast_response); // O(r) number of "\n" occurances
foreach( $response_lines as $data_line){ // O(r)
$message_data = explode(':',$data_line); // O(d) number of ":" occurances
if($message_data[0] == "OK"){
echo "The message to ".$message_data[1]." was successful, with reference ".$message_data[2]."\n";
}elseif( $message_data[0] == "BAD" ){
echo "The message to ".$message_data[1]." was NOT successful. Reason: ".$message_data[2]."\n";
}elseif( $message_data[0] == "ERROR" ){
echo "There was an error with this request. Reason: ".$message_data[1]."\n";
}
}
}
}
}
Here's a list of what I did:
removed the for loop from bottom and echo the $message directly from the main loop instead
removed $ref var
initialized $destination, $text, $content, $response_lines, $smsbroadcast_response and $message_data vars outside the for loop since declaring them inside the loop with each iteration is sub-optimal
That's all I can think about for now.
Notes for further improvements:
I'd investigate on the performance of sendSMS that you're using. It could be one of the components that are slowing things down.
In order to dig deeper, a helpful tool for analyzing performance is big Oh notation. So I've added comments to label loop components.
Because we're looking at multiple nested loops we generally have something like O(N^3) here.
However, we could write that equation to be more detailed such as this:
O( n * (v + 2r) * d)
(please check code comments to see what each variable represents)
Since you're asking for a high "n" (number of members) I'd investigate ways to make the other variables like "v", "r" or "d" smaller.
Eliminating any of these variables altogether like removing
$message_data = explode(':',$data_line);
have the highest positive impact on performance (given that is still achieves the same functionality).