alluxio.client.file.cache

Interface PageStore

All Superinterfaces:

AutoCloseable

All Known Implementing Classes:

LocalPageStore, RocksPageStore, TimeBoundPageStore

public interface PageStore
extends AutoCloseable

A simple abstraction on the storage to put, get and delete pages. The implementation of this class does not need to provide thread-safety.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	PageStore.Metrics Metrics.

Field Summary

Fields

Modifier and Type	Field and Description
static org.slf4j.Logger	LOG

Method Summary

Modifier and Type	Method and Description
static PageStore	create(PageStoreOptions options) Creates a new PageStore.
void	delete(PageId pageId) Deletes a page from the store.
default int	get(PageId pageId, byte[] buffer) Gets a page from the store to the destination buffer.
int	get(PageId pageId, int pageOffset, int bytesToRead, byte[] buffer, int bufferOffset) Gets part of a page from the store to the destination buffer.
long	getCacheSize()
java.util.stream.Stream<PageInfo>	getPages() Gets a stream of all pages from the page store.
static Path	getStorePath(PageStoreType storeType, String rootDir) Gets store path given root directory and store type.
static void	initialize(PageStoreOptions options) Initializes a page store at the configured location.
static PageStore	open(PageStoreOptions options) Opens an existing PageStore.
void	put(PageId pageId, byte[] page) Writes a new page from a source channel to the store.

Methods inherited from interface java.lang.AutoCloseable

close

Field Detail

LOG

static final org.slf4j.Logger LOG

Method Detail

create

static PageStore create(PageStoreOptions options)
                 throws IOException

Creates a new PageStore. Previous state in the samme cache dir will be overwritten.

Parameters:

options - the options to instantiate the page store

Returns:

a PageStore instance

Throws:

IOException - if I/O error happens

open

static PageStore open(PageStoreOptions options)
               throws IOException

Opens an existing PageStore.

Parameters:

options - the options to instantiate the page store

Returns:

a PageStore instance

Throws:

IOException - if I/O error happens

getStorePath

static Path getStorePath(PageStoreType storeType,
                         String rootDir)

Gets store path given root directory and store type.

Parameters:

storeType - the type of the page store

rootDir - the root directory path

Returns:

the store directory path

initialize

static void initialize(PageStoreOptions options)
                throws IOException

Initializes a page store at the configured location. Data from different store type will be removed.

Parameters:

options - initialize a new page store based on the options

Throws:

IOException - when failed to clean up the specific location

put

void put(PageId pageId,
         byte[] page)
  throws ResourceExhaustedException,
         IOException

Writes a new page from a source channel to the store.

Parameters:

pageId - page identifier

page - page data

Throws:

ResourceExhaustedException - when there is not enough space found on disk

IOException - when the store fails to write this page

get

default int get(PageId pageId,
                byte[] buffer)
         throws IOException,
                PageNotFoundException

Gets a page from the store to the destination buffer.

Parameters:

pageId - page identifier

buffer - destination buffer

Returns:

the number of bytes read

Throws:

IOException - when the store fails to read this page

PageNotFoundException - when the page isn't found in the store

get

int get(PageId pageId,
        int pageOffset,
        int bytesToRead,
        byte[] buffer,
        int bufferOffset)
 throws IOException,
        PageNotFoundException

Gets part of a page from the store to the destination buffer.

Parameters:

pageId - page identifier

pageOffset - offset within page

bytesToRead - bytes to read in this page

buffer - destination buffer

bufferOffset - offset in buffer

Returns:

the number of bytes read

Throws:

IOException - when the store fails to read this page

PageNotFoundException - when the page isn't found in the store

IllegalArgumentException - when the page offset exceeds the page size

delete

void delete(PageId pageId)
     throws IOException,
            PageNotFoundException

Deletes a page from the store.

Parameters:

pageId - page identifier

Throws:

IOException - when the store fails to delete this page

PageNotFoundException - when the page isn't found in the store

getPages

java.util.stream.Stream<PageInfo> getPages()
                                    throws IOException

Gets a stream of all pages from the page store. This stream needs to be closed as it may open IO resources.

Returns:

a stream of all pages from page store

Throws:

IOException - if any error occurs

getCacheSize

long getCacheSize()

Returns:

an estimated cache size in bytes