TYPO3 Core

An error occurs when I try to index external documents like PDF:
Warning: ociexecute() [function.ociexecute]: ORA-00001: unique constraint (INTRANET.SYS_C0090792) violated in ...\typo3\sysext\adodb\adodb\drivers\adodb-oci8.inc.php on line 1017

In the dbal-Log I see this (example):
sqlError ORA-00001: unique constraint (*.SYS_C0090792) violated

INSERT INTO "index_words" ( "wid", "baseword", "metaphone" ) VALUES ( '88728859', 'schalter', '212743736' )

This error means there is already one record with this "wid" ("wid" is the key).

So I tried to fix this bug and found something interesting on typo3\sysext\indexed_search\class.indexer.php on line 1843: "// A duplicate-key error will occur here if a word is NOT unset in the unset() line. However as long as the words in $wl are NOT longer as 60 chars (the baseword varchar is 60 characters...) this is not a problem."
This may be true on MySQL, but with Oracle it failes.

So I fixed the function like this:
function checkWordList($wl) {
reset($wl);
$phashArr = array();
while(list($key,) = each($wl)) {
$phashArr[] = $wl[$key]['hash'];
}
if (count($phashArr)) {
$cwl = implode(',',$phashArr);
$res = $GLOBALS['TYPO3_DB']->exec_SELECTquery('baseword', 'index_words', 'wid IN ('.$cwl.')');

if($GLOBALS['TYPO3_DB']->sql_num_rows($res)!=count($wl)) {
                $this->log_setTSlogMessage('Inserting words: '.(count($wl)-$GLOBALS['TYPO3_DB']->sql_num_rows($res)),1);
                while($row = $GLOBALS['TYPO3_DB']->sql_fetch_assoc($res)) {
                    unset($wl[$row['baseword']]);
                }

reset($wl);
                while(list($key,$val)=each($wl)) {
                    $insertFields = array(
                        'wid' => $val['hash'],
                        'baseword' => $key,
                        'metaphone' => $val['metaphone']
                    );
/* NEW: FIX /
                    $res = $GLOBALS['TYPO3_DB']->exec_SELECTquery('', 'index_words', 'wid = \''.$val['hash'].'\'');
                    if($GLOBALS['TYPO3_DB']->sql_num_rows($res)==0) {
                        $GLOBALS['TYPO3_DB']->exec_INSERTquery('index_words', $insertFields);
                    }
/* END FIX */
                }
            }
        }
    }

Now it works.
Can please anyone check the fix and give me feedback?

Indexed Search Engine version is 2.10.0
(issue imported from #M6369)