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Aerospike::scan

Aerospike::scan - scans a set in the Aerospike database

Description

public int Aerospike::scan ( string $ns, string $set, callback $record_cb [, array $select [, array $options ]] )

Aerospike::scan() will scan a set and invoke a callback function record_cb on each record in the result stream. A selection of bins returned can be determined by passing an array in select, otherwise all bins in the record are returned. . Non-existent bins will appear in the record with a NULL value.

Parameters

ns the namespace

set the set to be scanned

record_cb a callback function invoked for each record streaming back from the server.

select an array of bin names which are the subset to be returned.

options including

  • Aerospike::OPT_READ_TIMEOUT
  • Aerospike::OPT_SCAN_PRIORITY
  • Aerospike::OPT_SCAN_PERCENTAGE of the records in the set to return
  • Aerospike::OPT_SCAN_CONCURRENTLY whether to run the scan in parallel
  • Aerospike::OPT_SCAN_NOBINS whether to not retrieve bins for the records

Return Values

Returns an integer status code. Compare to the Aerospike class status constants. When non-zero the Aerospike::error() and Aerospike::errorno() methods can be used.

Examples

Get 20 records from a scan

<?php

$config = array("hosts"=>array(array("addr"=>"localhost", "port"=>3000)));
$db = new Aerospike($config);
if (!$db->isConnected()) {
   echo "Aerospike failed to connect[{$db->errorno()}]: {$db->error()}\n";
   exit(1);
}

$options = array(Aerospike::OPT_SCAN_PRIORITY => Aerospike::SCAN_PRIORITY_MEDIUM);
$processed = 0;
$status = $db->scan("test", "users", function ($record) use (&$processed) {
    if (!is_null($record['bins']['email'])) echo $record['bins']['email']."\n";
    if ($processed++ > 19) return false; // halt the stream by returning a false
}, array("email"), $options);
// check the status of the last operation
if ($status == Aerospike::ERR_SCAN_ABORTED) {
    echo "I think a sample of $processed records is enough\n";
} else if ($status !== Aerospike::OK) {
    echo "An error occured while scanning[{$db->errorno()}] {$db->error()}\n";
}

?>

We expect to see:

foo@example.com
:
bar@example.com
I think a sample of 20 records is enough

Buffer all the records returned from the scan

<?php

$result = array();
$status = $db->scan("test", "users", function ($record) use (&$results) {
    $result[] = $record['bins'];
});
if ($status !== Aerospike::OK) {
    echo "An error occured while scanning[{$db->errorno()}] {$db->error()}\n";
} else {
    echo "The scan returned ".count($result)." records\n";
}

?>

See Also