Curl_init () Related issues

Curl_init () issue
I pass an XML document with Curl_init ()
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$sql = "Select AA from BB";
$n = $DB->execsql ($sql);
while ($DB->fetch ()) {
$MD 5 = MD5 ($SRC. " &key=6c3d80558fec2784b20a95863dca9458 ");
$WEB = new Web_service ($HOST, N, $URL, "POST");
$WEB->addpara ("Para_xml", $SRC);
$WEB->addpara ("Md5data", $MD 5);
$WEB->addpara ("Customersid", "10058");
$ret = $WEB->run ();
$WEB->close (); }

The Run () function is approximate
$ch = Curl_init ();
curl_setopt ($ch, Curlopt_url, "http://". $this->ip. $this->url);
curl_setopt ($ch, Curlopt_returntransfer, true);
curl_setopt ($ch, Curlopt_post, 1);
curl_setopt ($ch, Curlopt_postfields, $this->parameter);
$ret = curl_exec ($ch);
Curl_close ($ch);

Issue: The SQL statement detected 1000 data, but there may be 10 unsuccessful. If the unsuccessful 10 data transmission again, and the transmission is successful.
I found the problem is that in the loop repeatedly connected pages, sometimes the connection is not successful, that is, $ret = $WEB->run (); Returns a null value. So no transmission was successful.
How should such a problem be solved??
Do you want to add a sleep () after each data transfer to control the time of the repeat connection trigger?

------Solution--------------------
You can try it with sleep.
------Solution--------------------
You can see if the delivery is successful through Curl_getinfo.
You can also collect all the data, one-time pass
You can also pass it in multi-channel mode (CURL_MULTI)
------Solution--------------------
The status should be recorded, except for the completion of the re-submission

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