Schema Metadata

PHP Driver exposes the Cassandra Schema Metadata for keyspaces, tables, and columns.

Background

Given

a running Cassandra cluster

And

the following schema:

CREATE KEYSPACE simplex WITH replication = {
  'class': 'SimpleStrategy',
  'replication_factor': 1
} AND DURABLE_WRITES = false;
USE simplex;
CREATE TABLE values (
  id int PRIMARY KEY,
  bigint_value bigint,
  decimal_value decimal,
  double_value double,
  float_value float,
  int_value int,
  varint_value varint,
  ascii_value ascii,
  text_value text,
  varchar_value varchar,
  timestamp_value timestamp,
  blob_value blob,
  uuid_value uuid,
  timeuuid_value timeuuid,
  inet_value inet,
  list_value List<text>,
  map_value Map<timestamp, double>,
  set_value Set<float>
) WITH
    bloom_filter_fp_chance=0.5 AND
    caching='ALL' AND
    comment='Schema Metadata Feature' AND
    compaction={'class': 'LeveledCompactionStrategy', 'sstable_size_in_mb' : 37} AND
    compression={'sstable_compression': 'DeflateCompressor'} AND
    dclocal_read_repair_chance=0.25 AND
    gc_grace_seconds=3600 AND
    populate_io_cache_on_flush='true' AND
    read_repair_chance=0.75 AND
    replicate_on_write='false';

Getting keyspace metadata

Given

the following example:

<?php
$cluster  = Cassandra::cluster()
                   ->withContactPoints('127.0.0.1')
                   ->build();
$session  = $cluster->connect("simplex");

$schema   = $session->schema();
$keyspace = $schema->keyspace("simplex");

echo "Name: " . $keyspace->name() . "\n";
echo "Replication Class: " . $keyspace->replicationClassName() . "\n";
foreach ($keyspace->replicationOptions() as $key => $value) {
  echo "  " . $key . ":" . $value . "\n";
}
echo "Has Durable Writes: " . ($keyspace->hasDurableWrites() ? "True" : "False" ). "\n";

When

it is executed

Then

its output should contain:

Name: simplex
Replication Class: org.apache.cassandra.locator.SimpleStrategy
  replication_factor:1
Has Durable Writes: False

Getting table metadata

Given

the following example:

<?php
$cluster = Cassandra::cluster()
                   ->withContactPoints('127.0.0.1')
                   ->build();
$session = $cluster->connect("simplex");

$schema  = $session->schema();
$table   = $schema->keyspace("simplex")->table("values");

echo "Name: " . $table->name() . "\n";
echo "Bloom Filter: " . $table->bloomFilterFPChance() . "\n";
$patterns = array('/{/', '/"/', '/:/', '/keys/');
$table_caching = explode(",", $table->caching());
echo "Caching: " . preg_replace($patterns, "", $table_caching[0]) . "\n";
echo "Comment: " . $table->comment() . "\n";
echo "Compaction Class: " . $table->compactionStrategyClassName() . "\n";
foreach ($table->compactionStrategyOptions() as $key => $value) {
  echo "  " . $key . ":" . $value . "\n";
}
foreach ($table->compressionParameters() as $key => $value) {
  echo "  " . $key . ":" . $value . "\n";
}
echo "DC/Local Read Repair Chance: " . $table->localReadRepairChance() . "\n";
echo "Garbage Collection Grace Seconds: " . $table->gcGraceSeconds() . "\n";
echo "Read Repair Chance: " . $table->readRepairChance() . "\n";

When

it is executed

Then

its output should contain:

Name: values
Bloom Filter: 0.5
Caching: ALL
Comment: Schema Metadata Feature
Compaction Class: org.apache.cassandra.db.compaction.LeveledCompactionStrategy
  sstable_size_in_mb:37
  sstable_compression:org.apache.cassandra.io.compress.DeflateCompressor
DC/Local Read Repair Chance: 0.25
Garbage Collection Grace Seconds: 3600
Read Repair Chance: 0.75

until cassadra v2.1

Getting table metadata for io cache and replicate on write

Given

the following example:

<?php
$cluster = Cassandra::cluster()
                   ->withContactPoints('127.0.0.1')
                   ->build();
$session = $cluster->connect("simplex");

$schema  = $session->schema();
$table   = $schema->keyspace("simplex")->table("values");

echo "Populate I/O Cache on Flush: " . ($table->populateIOCacheOnFlush() ? "True" : "False") . "\n";
echo "Replicate on Write: " . ($table->replicateOnWrite() ? "True" : "False") . "\n";

When

it is executed

Then

its output should contain:

Populate I/O Cache on Flush: True
Replicate on Write: False

only on cassadra v2.0

Getting table metadata for index interval

Given

the following example:

<?php
$cluster = Cassandra::cluster()
                   ->withContactPoints('127.0.0.1')
                   ->build();
$session = $cluster->connect("simplex");
$cql = "ALTER TABLE values WITH index_interval = '512'";
$session->execute($cql);
$schema  = $session->schema();
$table   = $schema->keyspace("simplex")->table("values");

echo "Index Interval: " . $table->indexInterval() . "\n";

When

it is executed

Then

its output should contain:

Index Interval: 512

since cassadra v2.0

Getting table metadata for default TTL, memtable flush period and speculative retry

Given

the following example:

<?php
$cluster = Cassandra::cluster()
                   ->withContactPoints('127.0.0.1')
                   ->build();
$session = $cluster->connect("simplex");
$cql = "ALTER TABLE values WITH default_time_to_live = '10000' AND "
       . "memtable_flush_period_in_ms = '100' AND "
       . "speculative_retry = '10ms'";
$session->execute($cql);
$schema  = $session->schema();
$table   = $schema->keyspace("simplex")->table("values");

echo "Default TTL: " . $table->defaultTTL() . "\n";
echo "Memtable Flush Period: " . $table->memtableFlushPeriodMs() . "\n";
echo "Speculative Retry: " . intval($table->speculativeRetry()) . "\n";

When

it is executed

Then

its output should contain:

Default TTL: 10000
Memtable Flush Period: 100
Speculative Retry: 10

since cassadra v2.1

Getting table metadata for max and min index intervals

Given

the following example:

<?php
$cluster = Cassandra::cluster()
                   ->withContactPoints('127.0.0.1')
                   ->build();
$session = $cluster->connect("simplex");
$cql = "ALTER TABLE values WITH max_index_interval = '16' AND "
       . "min_index_interval = '4'";
$session->execute($cql);
$schema  = $session->schema();
$table   = $schema->keyspace("simplex")->table("values");

echo "Maximum Index Interval: " . $table->maxIndexInterval() . "\n";
echo "Minimum Index Interval: " . $table->minIndexInterval() . "\n";

When

it is executed

Then

its output should contain:

Maximum Index Interval: 16
Minimum Index Interval: 4

since cassadra v2.0

Getting metadata for column and types

Given

the following example:

<?php
$cluster   = Cassandra::cluster()
                   ->withContactPoints('127.0.0.1')
                   ->build();
$session   = $cluster->connect("simplex");
$schema    = $session->schema();
$table     = $schema->keyspace("simplex")->table("values");
foreach ($table->columns() as $column) {
    echo $column->name() . ': ' . $column->type() . "\n";
}

When

it is executed

Then

its output should contain these lines in any order:

ascii_value: ascii
bigint_value: bigint
blob_value: blob
decimal_value: decimal
double_value: double
float_value: float
id: int
inet_value: inet
int_value: int
list_value: list<varchar>
map_value: map<timestamp, double>
set_value: set<float>
text_value: varchar
timestamp_value: timestamp
timeuuid_value: timeuuid
uuid_value: uuid
varchar_value: varchar
varint_value: varint

since cassadra v2.1

Getting metadata for user types

Given

the following schema:

CREATE KEYSPACE simplex WITH replication = {
  'class': 'SimpleStrategy',
  'replication_factor': 1
};
USE simplex;
CREATE TYPE type1 (a int, b text);
CREATE TYPE type2 (a map<text, int>, b bigint);
CREATE TYPE type3 (a map<text, frozen<set<varint>>>, b list<uuid>);

And

the following example:

<?php
$cluster   = Cassandra::cluster()
                   ->withContactPoints('127.0.0.1')
                   ->build();
$session   = $cluster->connect("simplex");
$schema    = $session->schema();
$keyspace  = $schema->keyspace("simplex");

foreach ($keyspace->userTypes() as $name => $type) {
  print "Name: $type\n";
  print "Type: " . var_export($type, true) . "\n";
}

When

it is executed

Then

its output should contain:

Name: simplex.type1
Type: Cassandra\Type\UserType::__set_state(array(
   'types' =>
  array (
    'a' =>
    Cassandra\Type\Scalar::__set_state(array(
       'name' => 'int',
    )),
    'b' =>
    Cassandra\Type\Scalar::__set_state(array(
       'name' => 'varchar',
    )),
  ),
))
Name: simplex.type2
Type: Cassandra\Type\UserType::__set_state(array(
   'types' =>
  array (
    'a' =>
    Cassandra\Type\Map::__set_state(array(
       'keyType' =>
      Cassandra\Type\Scalar::__set_state(array(
         'name' => 'varchar',
      )),
       'valueType' =>
      Cassandra\Type\Scalar::__set_state(array(
         'name' => 'int',
      )),
    )),
    'b' =>
    Cassandra\Type\Scalar::__set_state(array(
       'name' => 'bigint',
    )),
  ),
))
Name: simplex.type3
Type: Cassandra\Type\UserType::__set_state(array(
   'types' =>
  array (
    'a' =>
    Cassandra\Type\Map::__set_state(array(
       'keyType' =>
      Cassandra\Type\Scalar::__set_state(array(
         'name' => 'varchar',
      )),
       'valueType' =>
      Cassandra\Type\Set::__set_state(array(
         'valueType' =>
        Cassandra\Type\Scalar::__set_state(array(
           'name' => 'int',
        )),
      )),
    )),
    'b' =>
    Cassandra\Type\Collection::__set_state(array(
       'valueType' =>
      Cassandra\Type\Scalar::__set_state(array(
         'name' => 'uuid',
      )),
    )),
  ),
))

Disable schema metadata

Given

the following example:

<?php
$cluster   = Cassandra::cluster()
                   ->withContactPoints('127.0.0.1')
                   ->withSchemaMetadata(false)
                   ->build();
$session   = $cluster->connect("simplex");
$schema    = $session->schema();
print count($schema->keyspaces()) . "\n";

When

it is executed

Then

its output should contain these lines in any order:

Contents

Schema Metadata

Background

Getting keyspace metadata

Getting table metadata

Getting table metadata for io cache and replicate on write

Getting table metadata for index interval

Getting table metadata for default TTL, memtable flush period and speculative retry

Getting table metadata for max and min index intervals

Getting metadata for column and types

Getting metadata for user types

Disable schema metadata