php - DynamoDb retrieve data Order by descending order and then use pagination like sql syntax -

i facing problem retrieve records in descending order pagination limit amazon dynamodb in mysql. using following script, gives unordered list of records. need last inserted id on top.

$limit      =   10; $total = 0; $start_key = null; $params = array('tablename' => 'event','attributestoget' =>array('id','interactiondate','repname','totalamount','fooding','nonfooding','pdfdocument','ismultiple','payment_mode','interaction_type','products','programtitle','venue','workstepid','foodingother','interaction_type_other'), 'scanfilter'=> array('manufacturername' => array("comparisonoperator" => "eq", "attributevaluelist" => array(array("s" => "$manufacturername")))),'limit'=>$limit ); $itemsarray = array(); $itemsarray = array(); $finalitemsarray = array();  $finalcrmrecords = array(); do{ if(!empty($start_key)){              $params['exclusivestartkey'] = $start_key->getarraycopy(); } $response = $this->amazon->dynamodb->scan($params);      if ($response->status == 200) { $counter = (string) $response->body->count; $total += $counter; foreach($response->body->items $itemsarray){ $finalitemsarray[]  =   $itemsarray;     } if($total>$limit){ $i =1; foreach($response->body->items $items){ $finalitemsarray[]      =   $items; if($i == $limit){ $start_key = $items->id->{amazondynamodb::type_number}->to_array(); $finalcrmrecords['data']    =   $finalitemsarray; $finalcrmrecords['start_key']   =   $start_key; break; } $i++; } }elseif($total<$limit){ $start_key = $response->body->lastevaluatedkey->to_array(); }else{ $finalcrmrecords['data']    =   $finalitemsarray; if ($response->body->lastevaluatedkey) { $start_key =$response->body->lastevaluatedkey->to_array(); break; } else { $start_key = null; } $finalcrmrecords['start_key']   =   $start_key;  } }        }while($start_key); 

regards

sandeep kumar sinha

a scan operation in dynamodb can not change sorting of returned items. scan pretty expensive operation requires read whole table.

if want take advantage of dynamodb, here's 1 advice:

instead of looking information, try find it.

in sense of, use lookups instead of scan/query information need.

as example, if have table stores events. store events in table, eventid hashkey. can have second table eventlookups store lookups eventids. in eventlookups table put item lookupid: latest-event referencing eventid: .... every time insert new events can update latest-event entry point newer event. or use set store latest 50 eventids events in 1 item.

-mathias