Batch statements

PHP Driver supports batch statements. There are three types of batch statements:

• Cassandra::BATCH_LOGGED - this is the default batch type. This batch guarantees that either all or none of its statements will be executed. This behavior is achieved by writing a batch log on the coordinator, which slows down the execution somewhat.
• Cassandra::BATCH_UNLOGGED - this batch will not be verified when executed, which makes it faster than a LOGGED batch, but means that some of its statements might fail, while others - succeed.
• Cassandra::BATCH_COUNTER - this batch is used for counter updates, which are, unlike other writes, not idempotent.

Background

Given

a running Cassandra cluster

And

the following schema:

CREATE KEYSPACE simplex WITH replication = {
  'class': 'SimpleStrategy',
  'replication_factor': 1
};
USE simplex;
CREATE TABLE playlists (
  id uuid,
  title text,
  album text,
  artist text,
  song_id uuid,
  PRIMARY KEY (id, title, album, artist)
);

Batch statements can contain simple and prepared statements

Given

the following example:

<?php
$cluster   = Cassandra::cluster()
               ->withContactPoints('127.0.0.1')
               ->build();
$session   = $cluster->connect("simplex");
$prepared  = $session->prepare(
               "INSERT INTO playlists (id, song_id, artist, title, album) " .
               "VALUES (62c36092-82a1-3a00-93d1-46196ee77204, ?, ?, ?, ?)"
             );
$simple    = new Cassandra\SimpleStatement(
               "INSERT INTO playlists (id, song_id, artist, title, album) " .
               "VALUES (62c36092-82a1-3a00-93d1-46196ee77204, ?, ?, ?, ?)"
             );
$batch     = new Cassandra\BatchStatement(Cassandra::BATCH_LOGGED);

$batch->add($prepared, array(
    'song_id' => new Cassandra\Uuid('756716f7-2e54-4715-9f00-91dcbea6cf50'),
    'title'   => 'La Petite Tonkinoise',
    'album'   => 'Bye Bye Blackbird',
    'artist'  => 'Joséphine Baker'
));

$batch->add($simple, array(
    new Cassandra\Uuid('f6071e72-48ec-4fcb-bf3e-379c8a696488'),
    'Willi Ostermann', 'Die Mösch', 'In Gold',
));

$batch->add($prepared, array(
    new Cassandra\Uuid('fbdf82ed-0063-4796-9c7c-a3d4f47b4b25'),
    'Mick Jager', 'Memo From Turner', 'Performance'
));

$session->execute($batch);

$statement = new Cassandra\SimpleStatement("SELECT * FROM simplex.playlists");
$result    = $session->execute($statement);

foreach ($result as $row) {
  echo $row['artist'] . ": " . $row['title'] . " / " . $row['album'] . "\n";
}

When

it is executed

Then

its output should contain:

Joséphine Baker: La Petite Tonkinoise / Bye Bye Blackbird

And

its output should contain:

Willi Ostermann: Die Mösch / In Gold

And

its output should contain:

Mick Jager: Memo From Turner / Performance