Flow PHP

PageHeader

Properties

$_TSPEC : mixed
$compressed_page_size : int: Compressed (and potentially encrypted) page size in bytes, not including this header *.
$crc : int: The 32-bit CRC checksum for the page, to be be calculated as follows:
$data_page_header : DataPageHeader
$data_page_header_v2 : DataPageHeaderV2
$dictionary_page_header : DictionaryPageHeader
$index_page_header : IndexPageHeader
$isValidate : mixed
$type : int: the type of the page: indicates which of the *_header fields is set *.
$uncompressed_page_size : int: Uncompressed page size in bytes (not including this header) *.

Methods

__construct() : mixed
getName() : mixed
read() : mixed
write() : mixed

$_TSPEC


    public
    static    mixed
    $_TSPEC
     = [1 => ['var' => 'type', 'isRequired' => true, 'type' => \Thrift\Type\TType::I32, 'class' => '\Flow\Parquet\Thrift\PageType'], 2 => ['var' => 'uncompressed_page_size', 'isRequired' => true, 'type' => \Thrift\Type\TType::I32], 3 => ['var' => 'compressed_page_size', 'isRequired' => true, 'type' => \Thrift\Type\TType::I32], 4 => ['var' => 'crc', 'isRequired' => false, 'type' => \Thrift\Type\TType::I32], 5 => ['var' => 'data_page_header', 'isRequired' => false, 'type' => \Thrift\Type\TType::STRUCT, 'class' => '\Flow\Parquet\Thrift\DataPageHeader'], 6 => ['var' => 'index_page_header', 'isRequired' => false, 'type' => \Thrift\Type\TType::STRUCT, 'class' => '\Flow\Parquet\Thrift\IndexPageHeader'], 7 => ['var' => 'dictionary_page_header', 'isRequired' => false, 'type' => \Thrift\Type\TType::STRUCT, 'class' => '\Flow\Parquet\Thrift\DictionaryPageHeader'], 8 => ['var' => 'data_page_header_v2', 'isRequired' => false, 'type' => \Thrift\Type\TType::STRUCT, 'class' => '\Flow\Parquet\Thrift\DataPageHeaderV2']]

$compressed_page_size

Compressed (and potentially encrypted) page size in bytes, not including this header *.


    public
        int
    $compressed_page_size

$crc

The 32-bit CRC checksum for the page, to be be calculated as follows:


    public
        int
    $crc

The standard CRC32 algorithm is used (with polynomial 0x04C11DB7, the same as in e.g. GZip).
All page types can have a CRC (v1 and v2 data pages, dictionary pages, etc.).
The CRC is computed on the serialization binary representation of the page (as written to disk), excluding the page header. For example, for v1 data pages, the CRC is computed on the concatenation of repetition levels, definition levels and column values (optionally compressed, optionally encrypted).
The CRC computation therefore takes place after any compression and encryption steps, if any.

If enabled, this allows for disabling checksumming in HDFS if only a few pages need to be read.

$data_page_header


    public
        DataPageHeader
    $data_page_header

$data_page_header_v2


    public
        DataPageHeaderV2
    $data_page_header_v2

$dictionary_page_header


    public
        DictionaryPageHeader
    $dictionary_page_header

$index_page_header


    public
        IndexPageHeader
    $index_page_header

$isValidate


    public
    static    mixed
    $isValidate
     = false

$type

the type of the page: indicates which of the *_header fields is set *.


    public
        int
    $type

$uncompressed_page_size

Uncompressed page size in bytes (not including this header) *.


    public
        int
    $uncompressed_page_size

__construct()


    public
                    __construct([mixed $vals = null ]) : mixed

Parameters

$vals : mixed = null

getName()


    public
                    getName() : mixed

read()


    public
                    read(mixed $input) : mixed

Parameters

$input : mixed

write()


    public
                    write(mixed $output) : mixed

Parameters

$output : mixed