Inserting Hundreds of Thousands of Posts at Once

I have a project in which I create an array of 200k+ lines w/ 25 fields that run the wp_insert_post and update_post_meta. To start it processes pretty fast the slows down a lot after 10k records or so.

Is there a more efficient way to do this? Is there a MySQL stored procedure that exists so I can create these posts directly using SQL queries and skip the PHP?

echo "get list of posts to be created in wordpress n";
//RETURNS ALL OFFER DATA OF POSTS THAT NEED TO BE ADDED
$sql = "SELECT a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z FROM offer WHERE modified = '1';";
$rst = $wpdb->get_results($sql,ARRAY_N); //run query
if(is_null($rst)){
  echo mysql_error() . "n";
}else{
  echo "done n";
}
echo "creating posts n";;
foreach($rst as $r){
  //print_r($r);
  $my_post = array(
       'post_title' => $r[0],
       'post_status' => 'publish',
       'post_author' => 72,
       'post_category' => array(16)
    );

  // Insert the post into the database
  $newOffer = wp_insert_post( $my_post );

  if(!$newOffer){
    echo "problem creating the post " . $r[0];
  }

  array_unshift($r,$newOffer); // so that the data positions matches when calling updateMetaData 

  if($newOffer){
    updateMetaData($newOffer,$r);
  }
}

function updateMetaData($id,$data){
  global $wpdb;
  $category = $wpdb->get_results('SELECT categoryName FROM category WHERE categoryIdentifier ="'.mysql_escape_string($data[8]).'"');
  if($category){
    wp_set_object_terms( $id, array($category[0]->categoryName,16), 'category');
  }

  update_post_meta($id,'a','yes');
  update_post_meta($id,'b',$data[1]);
  $year = substr($data[2],0, -4);
  $mon = substr($data[2], -4, 2);
  $day = substr($data[2], -2); 
  update_post_meta($id,'c',$mon."/".$day."/".$year." 12:00:00 AM");
  $year = substr($data[3],0, -4);
  $mon = substr($data[3], -4, 2);
  $day = substr($data[3], -2); 
  update_post_meta($id,'d',$mon."/".$day."/".$year." 12:00:00 AM");
  update_post_meta($id,'e',$data[4]);//description
  update_post_meta($id,'f',$data[5]);
  update_post_meta($id,'g',$data[6]);
  update_post_meta($id,'h',$data[7]);
  update_post_meta($id,'i',$data[8]);
  update_post_meta($id,'j',$data[9]);
  update_post_meta($id,'k',$data[10]);
  update_post_meta($id,'l',$data[11]);
  update_post_meta($id,'m',$data[12]);
  update_post_meta($id,'n',$data[13]);
  update_post_meta($id,'o',$data[14]);
  update_post_meta($id,'p',$data[15]);
  update_post_meta($id,'q',$data[16]);
  update_post_meta($id,'r',$data[17]);
  update_post_meta($id,'s',$data[18]);
  update_post_meta($id,'t',$data[19]);
  update_post_meta($id,'u',$data[20]);
  update_post_meta($id,'v',$data[21]);
  update_post_meta($id,'w',$data[22]);
  update_post_meta($id,'x',$data[23]);
  update_post_meta($id,'y',$data[24]);
  update_post_meta($id,'z',$data[25]);
  $year = null;
  $mon = null;
  $day = null;
  //echo "wordpress post meta updated.n";
}