php not clearing table between different queries - php

Question

I am using jquery to feed variables to a php page.
I want the php to clear a table in the database, load new data based on the variables, query the new data and echo out results.
The problem is, the php doesn't seem to be clearing the table each time I hit the php page. When I feed two sets of variables to the php page, the same results appear for both queries. The results are a combination of what I want. What am I doing wrong, anyone know?
jquery:
$.ajax({
url: "php/getTotals.php",
method: "POST",
data: {year : strYear, race: 'USP', type: strType},
success: function(data) {
var objPrez = jQuery.parseJSON(data);
fillTotal(objPrez, tbl_prezresults);
},
error: function(jxhr, statusText, err) {
console.log(statusText + " " + err);
}
});
//get gov totals
$.ajax({
url: "php/getTotals.php",
method: "POST",
data: {year : 2010, race: 'GOV', type: strType},
success: function(data) {
var objGov = jQuery.parseJSON(data);
fillTotal(objGov, tbl_govresults);
},
error: function(jxhr, statusText, err) {
console.log(statusText + " " + err);
}
});
getTotals.php:
require_once ('constants_test.php');
$db = new mysqli(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME);
if (mysqli_connect_errno()) {
printf("Connect failed: %s", mysqli_connect_error());
exit;
}
if( $_POST) {
$type = mysqli_real_escape_string($db, $_POST['type']);
$year = mysqli_real_escape_string($db, $_POST['year']);
$race = mysqli_real_escape_string($db, $_POST['race']);
$db->query("delete from elections_temp");
$data = array();
$q = "INSERT INTO elections_temp (SELECT * FROM elections where electionOffice = '" . $race . "' AND electionYear = '" . $year . "' AND electionType = '" . $type . "')";
$db->query($q);
$q_sums = "select firstName, lastName, party, sum(votes) as totvotes from elections_temp group by lastName order by totvotes desc";
$result = $db->query($q_sums);
while($row = $result->fetch_array(MYSQLI_ASSOC)) {
//Add this row to the reply
$data[] = $row;
}
echo json_encode($data);
$db->close();
} else {
echo "You shouldn't be here.";
}

Answer 1

What you are doing is the following:
2 ajax calls that call the php script at the same time (probably a delay of a few ms between them).
The server then does what you want it to do, but strange things happen because of your temp table that is created/truncated every request.
What happens is the following:
request1 enters
runs the php code
request2 enters
runs request2 code
request1run locks tem table in database and starts creating it and stuff
request2run wants to create the same temp tabel but can't because request1run is still doing stuff
request1run ends doing his stuff in the db temp table
request2run now does his thing with the temp table, delete all records and add stuff
request1run has to wait before he can select stuff from the temp table because request2run is still doing his business.
request2run finished creating the temp table and request1run can slect his data and return it to the client
request2run select data and returns it to the client
So, because you fire both ajax call at the same timen they end up messing with each other on the server.
Your server is probably not fast enough to handle request1 before request2 kicks in.

Answer 2

I think you do not need the extra table. You can all do it in one sql
$query = 'select firstName, lastName, party, sum(votes) as totvotes from elections
where electionOffice = "' . $race . '" AND electionYear = ' . $year . ' AND electionType = "' . $type . '"
group by lastName, firstName, party order by totvotes desc';
If performance is a problem, add an index to electionOffice, electionYear and electionType (all in one index).