4

When I have a loop like this:

foreach(...) {
  $r1 = $zend_db->fetchRow("SELECT ... ");
  $zend_table->insert($data_array, $where);
}

... running a few thousand times. Is it possible, that $r1 doesn't contain a record inserted in the previous loop?

At http://dev.mysql.com/doc/refman/5.1/en/query-cache.html they write "The query cache does not return stale data. When tables are modified, any relevant entries in the query cache are flushed." But maybe ZEND does some unexpected caching for SELECT or INSERT?

Do I need to use transactions to solve this?

I had an issue with double records and there is no other explanation where they came from. But I can't reproduce it, cause it happened two months ago, importing csv-data that no longer exists.

johjoh
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    ZF doesn't do any caching of database queries unless you use Zend_Cache to cache it yourself. Are you using PDO MySQL? The only reason I can think that `$r1` wouldn't contain a record from the previous loop is if the query failed and was unhandled, or if you are inserting to a master server and reading from a slave and the slave has not yet been updated. – drew010 Apr 18 '12 at 16:49
  • Was something else ... see my comment below. Thanks for eliminating the cache possibility! – johjoh Apr 19 '12 at 10:16

1 Answers1

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As said by drew010 in comment Zend_Db does no caching unless you implement it yourself . For next time to be sure about the problem try something like this

 try {
          foreach(...) {
      $r1 = $zend_db->fetchRow("SELECT ... ");
      $zend_table->insert($data_array, $where);
                       }
        } catch(Zend_Db_Exception $e)
            {

                $logger->log($e->getMessage(),Zend_Log::CRIT); //$logger is instance of Zend_Log
            }
Mr Coder
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  • Ok, thanks for making the clear! The INSERT didn't fail, as the record actually exists ... but was inserted a second time in the next loop (cause of double entries in the CSV), what I thought was because $r1 had no result. But now I realized that the condition for the INSERT wasn't safe. – johjoh Apr 19 '12 at 10:08