PHP script affecting local system storage - php

Question

I have a curious issue that is happening on my system when I run a PHP program I created. I am taking data from two tables and doing a comparison of data from Table A with Table B. If the record is not in Table A, then write that record to Table B. I discovered that the program works fine but, at least one record has to be in Table B first. After my first successful run Table A will have 16000+ records in it, now Table B has 15000+ or so records. I understand that there is going to be a bit of time for this to process. The curious thing is I noticed my hard drive is losing free space as the program runs. I have tried manually running the garbage collection. I also looked where the session files are being stored, only to find a few files that are rather small in size. I also tried adjusting the length of time that session files are stored from 1440 seconds to 30 secs. When I say that I am "losing" free space, there is something that is filling up my hard drive. I have gone from having 6GB to 5.75GB, if I allow the program to run longer, I only lose more space. I have also tried just simply restarting my system and I only regain a small portion of the space I lost. At this point I am unsure what I need to do to stop this from happening. Here is a sample of my code below:
<?php
include('./connect_local_pdo.php'); //Includes DB Connection Script
ini_set('max_execution_time', 5400); //5400 seconds = 90 minutes
gc_disable();
try {
$tbl_a_data = $conn->prepare('SELECT col_a, col_b, col_c from table_a');
$tbl_a_data->execute();
$tbl_b_data = $conn->prepare('SELECT col_a, col_b, col_c from table_b');
$tbl_b_data->execute();
$tbl_b_array = $tbl_b_data->fetchAll(PDO::FETCH_ASSOC);
while($tbl_a_array = $tbl_a_data->fetch(PDO::FETCH_ASSOC)){
foreach ($tbl_b_array as $tbl_b_array2){
if ($tbl_a_array['col_a'] !== $tbl_b_array2['col_a']){
$stmt = $conn->prepare("INSERT INTO table_b
(col_a, col_b, col_c)
VALUES
(:col_a, :col_b, :col_c)");
$stmt->bindParam(':col_a', $tbl_a_array['col_a']);
$stmt->bindParam(':col_b', $tbl_a_array['col_b']);
$stmt->bindParam(':col_c', $tbl_a_array['col_c']);
$stmt->execute();
} else {
$stmt = $conn->prepare("update table_b
set
col_b = table_a.col_b,
col_c = table_a.col_c
from table_a
where table_b.col_a = table_a.col_a ");
$stmt -> execute();
}
}
}
gc_collect_cycles();
gc_mem_caches();
clearstatcache();
} catch (PDOException $a) {
echo $a->getMessage();//Remove or change message in production code
}
Any assistance with this will be greatly appreciated! As of this post I have lost 2 gigs of space running this program.

Answer 1

With your line
include('./connect_local_pdo.php'); //Includes DB Connection Script
I assume it is a Database on localhost.
The Database is growing with your entries. It will take space to add rows.