ROOT::Experimental::Detail::RPagePool Class Reference

A thread-safe cache of column pages.

The page pool encapsulated memory management for data written into a tree or read from a tree. Adding and removing pages is thread-safe. All pages have the same size, which means different pages do not necessarily contain the same number of elements. Multiple page caches can coexist.

TODO(jblomer): it should be possible to register pages and to find them by column and index; this would facilitate pre-filling a cache, e.g. by read-ahead.

Definition at line 46 of file RPagePool.hxx.

Public Member Functions
	RPagePool (const RPagePool &)=delete
	RPagePool (std::size_t pageSize, std::size_t nPages)
	~RPagePool ()
void	CommitPage (const RPage &page)
	Registers a page that has previously been acquired by ReservePage() and was meanwhile filled with content. More...
RPage	GetPage (RColumn *column, NTupleSize_t index)
	Tries to find the page corresponding to column and index in the cache. More...
RPagePool &	operator= (const RPagePool &)=delete
void	ReleasePage (const RPage &page)
	Give back a page to the pool. There must not be any pointers anymore into this page. More...
RPage	ReservePage (RColumn *column)
	Get a new, empty page from the cache. Return a "null Page" if there is no more free space. More...

Private Attributes
void *	fMemory
std::size_t	fNPages
std::vector< RPage >	fPages
	TODO(jblomer): should be an efficient index structure that allows. More...
std::size_t	fPageSize
std::vector< std::uint32_t >	fReferences

#include <ROOT/RPagePool.hxx>

Constructor & Destructor Documentation

RPagePool() [1/2]

ROOT::Experimental::Detail::RPagePool::RPagePool	(	std::size_t	pageSize,
		std::size_t	nPages
	)

Definition at line 23 of file RPagePool.cxx.

RPagePool() [2/2]

ROOT::Experimental::Detail::RPagePool::RPagePool ( const RPagePool &  )

delete

~RPagePool()

ROOT::Experimental::Detail::RPagePool::~RPagePool

(

)

Definition at line 35 of file RPagePool.cxx.

Member Function Documentation

CommitPage()

void ROOT::Experimental::Detail::RPagePool::CommitPage

(

const RPage &

page

)

Registers a page that has previously been acquired by ReservePage() and was meanwhile filled with content.

Definition at line 57 of file RPagePool.cxx.

GetPage()

ROOT::Experimental::Detail::RPage ROOT::Experimental::Detail::RPagePool::GetPage	(	RColumn *	column,
		NTupleSize_t	index
	)

Tries to find the page corresponding to column and index in the cache.

On cache miss, load the page from the PageSource attached to the column and put it in the cache.

Definition at line 82 of file RPagePool.cxx.

operator=()

RPagePool & ROOT::Experimental::Detail::RPagePool::operator= ( const RPagePool &  )

delete

ReleasePage()

void ROOT::Experimental::Detail::RPagePool::ReleasePage

(

const RPage &

page

)

Give back a page to the pool. There must not be any pointers anymore into this page.

Definition at line 68 of file RPagePool.cxx.

ReservePage()

ROOT::Experimental::Detail::RPage ROOT::Experimental::Detail::RPagePool::ReservePage

(

RColumn *

column

)

Get a new, empty page from the cache. Return a "null Page" if there is no more free space.

Definition at line 41 of file RPagePool.cxx.

Member Data Documentation

fMemory

void* ROOT::Experimental::Detail::RPagePool::fMemory

private

Definition at line 48 of file RPagePool.hxx.

fNPages

std::size_t ROOT::Experimental::Detail::RPagePool::fNPages

private

Definition at line 50 of file RPagePool.hxx.

fPages

std::vector<RPage> ROOT::Experimental::Detail::RPagePool::fPages

private

TODO(jblomer): should be an efficient index structure that allows.

• random insert
• random delete
• searching by page
• searching by tree index

Definition at line 56 of file RPagePool.hxx.

fPageSize

std::size_t ROOT::Experimental::Detail::RPagePool::fPageSize

private

Definition at line 49 of file RPagePool.hxx.

fReferences

std::vector<std::uint32_t> ROOT::Experimental::Detail::RPagePool::fReferences

private

Definition at line 57 of file RPagePool.hxx.

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The documentation for this class was generated from the following files:

• tree/ntuple/v7/inc/ROOT/RPagePool.hxx
• tree/ntuple/v7/src/RPagePool.cxx