Retry Policies

PHP Driver supports consistency levels when executing statements.

Background

Given

a running Cassandra cluster

Given

the following logger settings:

dse.log=feature-retry-policy.log
dse.log_level=INFO

And

the following schema:

CREATE KEYSPACE simplex WITH replication = {
  'class': 'SimpleStrategy',
  'replication_factor': 3
};
USE simplex;
CREATE TABLE playlists (
  id uuid,
  title text,
  album text,
  artist text,
  song_id uuid,
  PRIMARY KEY (id, title, album, artist)
);

Retry policy can be set when constructing the cluster

Given

tracing is enabled

And

the following example:

$retry_policy = new Dse\RetryPolicy\DowngradingConsistency();
$cluster     = Dse::cluster()
                 ->withRetryPolicy(new Dse\RetryPolicy\Logging($retry_policy))
                 ->build();
$session     = $cluster->connect("simplex");
$statement   = $session->prepare("INSERT INTO playlists (id, song_id, artist, title, album)
                                 VALUES (62c36092-82a1-3a00-93d1-46196ee77204, ?, ?, ?, ?)");
$arguments   = array(new Dse\Uuid('756716f7-2e54-4715-9f00-91dcbea6cf50'),
                    'Joséphine Baker',
                    'La Petite Tonkinoise',
                    'Bye Bye Blackbird'
                    );
$options     = array(
                    'consistency' => Dse::CONSISTENCY_QUORUM,
                    'arguments' => $arguments
                    );
$session->execute($statement, $options);

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

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

When

it is executed

Then

its output should contain:

Joséphine Baker: La Petite Tonkinoise / Bye Bye Blackbird

Then

a log file “feature-retry-policy.log” should exist

And

the log file “feature-retry-policy.log” should contain “Retrying on unavailable error at consistency ONE”

Retry policy can be set when executing a statement

Given

tracing is enabled

And

the following example:

$retry_policy = new Dse\RetryPolicy\DowngradingConsistency();
$cluster     = Dse::cluster()->build();
$session     = $cluster->connect("simplex");
$statement   = $session->prepare("INSERT INTO playlists (id, song_id, artist, title, album)
                                  VALUES (62c36092-82a1-3a00-93d1-46196ee77204, ?, ?, ?, ?)");
$arguments   = array(new Dse\Uuid('756716f7-2e54-4715-9f00-91dcbea6cf50'),
                    'Joséphine Baker',
                    'La Petite Tonkinoise',
                    'Bye Bye Blackbird'
                    );
$options     = array(
                    'consistency' => Dse::CONSISTENCY_QUORUM,
                    'arguments' => $arguments,
                    'retry_policy' => new Dse\RetryPolicy\Logging($retry_policy)
                    );
$session->execute($statement, $options);

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

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

When

it is executed

Then

its output should contain:

Joséphine Baker: La Petite Tonkinoise / Bye Bye Blackbird

Then

a log file “feature-retry-policy.log” should exist

And

the log file “feature-retry-policy.log” should contain “Retrying on unavailable error at consistency ONE”

Retry policy can be set when executing a batch

Given

tracing is enabled

And

the following example:

$retry_policy = new Dse\RetryPolicy\DowngradingConsistency();
$cluster   = Dse::cluster()->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 Dse\SimpleStatement(
               "INSERT INTO playlists (id, song_id, artist, title, album) " .
               "VALUES (62c36092-82a1-3a00-93d1-46196ee77204, ?, ?, ?, ?)"
             );
$batch     = new Dse\BatchStatement(Dse::BATCH_UNLOGGED);

$options    = array(
                   'consistency' => Dse::CONSISTENCY_QUORUM,
                   'retry_policy' => new Dse\RetryPolicy\Logging($retry_policy)
              );

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

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

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

$session->execute($batch, $options);

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

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

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

Then

a log file “feature-retry-policy.log” should exist

And

the log file “feature-retry-policy.log” should contain “Retrying on unavailable error at consistency ONE”