On Thu, Oct 27, 2011 at 6:59 PM, <php@xxxxxxxxxxxxx> wrote:
> Running PHP 5.3.5 on FreeBSD 8.2 connecting to a MySQL 5.1.55
> server.
>
> Why does this code (below) run out of memory? It queries
> test_table for all rows, all fields and sorts them by the numeric
> 'contract' field. It then iterates through the rows, and tallies
> the number of rows per contract. That's not the end goal of the
> processing, but the processing does not require storing multiple
> rows in memory (except in the MySQL result buffer). One row at a
> time in memory is all I need.
>
> The schema is not huge:
>
> +--------------+-----------------+------+-----+---------+-------+
> | Field | Type | Null | Key | Default | Extra |
> +--------------+-----------------+------+-----+---------+-------+
> | contract | int(11) | YES | | NULL | |
> | A | int(8) unsigned | NO | | 0 | |
> | B | datetime | YES | | NULL | |
> | C | int(8) unsigned | YES | | 0 | |
> | D | char(8) | YES | | NULL | |
> | E | char(8) | YES | | 0000 | |
> | F | int(4) | YES | | 0 | |
> | G | int(1) | YES | | 0 | |
> | H | char(8) | YES | | 00:00 | |
> | I | varchar(100) | YES | | XXX | |
> +--------------+-----------------+------+-----+---------+-------+
>
>
> <?php
>
> require_once( '../include/mysql_funcs.php' );
>
> $db_host = $test_db_host;
> $db_user = $test_db_user;
> $db_name = $test_db_name;
> $db_pwd = $test_db_pwd;
>
> if (!($db_conn = mysql_connect( $db_host, $db_user, $db_pwd )))
> die( "Can't connect to MySQL server\n" );
>
> if (!mysql_select_db( $db_name, $db_conn ))
> die( "Can't connect to database $db_name\n" );
>
> $qry = "select * from test_table order by contract";
>
> if ($result = mysql_query( $qry, $db_conn )) {
>
> $row = mysql_fetch_array( $result );
> while ($row) {
> $c = $row[ 'contract' ];
> $n = 0;
> while ($row && ($c == $row[ 'contract' ])) {
> $n++;
> $row = mysql_fetch_array( $result );
> }
> echo sprintf( "|%13d |%7d |\n", $c, $n );
> } // while
>
> } else {
>
> die( mysql_error() . "\n" );
>
> }
>
> ?>
>
>
> The output ends with:
> ...
> | 39582 | 518 |
> | 39583 | 384 |
> | 39584 | 429 |
> | 39585 | 433 |
> | 39586 | 359 |
> PHP Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 20 bytes) in xx2.php on line 26
>
> Line 26 seems to be the innermost "mysql_fetch_array" call.
>
> The sum of the right-hand column for all the output produced
> prior to running out of memory is 274547. There are 295287 total
> rows in the table.
>
> What can I change to prevent this code from running out of memory
> even with an arbitrarily large number of rows returned from the
> 'select' query?
>
> Thank you for your time!
>
>
>
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>
>
I don't use the mysql functions, but rather the mysqli functions,
where you have to free resources (query results) when you're done with
them. Do you have to do the same thing with msql ?
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