org.apache.samza.table.descriptors

Class CachingTableDescriptor<K,V>

java.lang.Object

org.apache.samza.table.descriptors.BaseTableDescriptor<K,V,D>

org.apache.samza.table.descriptors.HybridTableDescriptor<K,V,CachingTableDescriptor<K,V>>

org.apache.samza.table.descriptors.CachingTableDescriptor<K,V>

Type Parameters:

K - type of the key in the cache

V - type of the value in the cache

All Implemented Interfaces:

TableDescriptor<K,V,CachingTableDescriptor<K,V>>

public class CachingTableDescriptor<K,V>
extends HybridTableDescriptor<K,V,CachingTableDescriptor<K,V>>

Table descriptor for a caching table.

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	CACHE_SIZE
static java.lang.String	CACHE_TABLE_ID
static java.lang.String	PROVIDER_FACTORY_CLASS_NAME
static java.lang.String	READ_TTL_MS
static java.lang.String	REAL_TABLE_ID
static java.lang.String	WRITE_AROUND
static java.lang.String	WRITE_TTL_MS

Fields inherited from class org.apache.samza.table.descriptors.BaseTableDescriptor

config, tableId

Constructor Summary

Constructors

Constructor and Description
CachingTableDescriptor(java.lang.String tableId, TableDescriptor<K,V,?> table) Constructs a table descriptor instance with internal cache
CachingTableDescriptor(java.lang.String tableId, TableDescriptor<K,V,?> table, TableDescriptor<K,V,?> cache) Constructs a table descriptor instance and specify a cache (as Table descriptor) to be used for caching.

Method Summary

Modifier and Type	Method and Description
java.lang.String	getProviderFactoryClassName() Return the fully qualified class name of the TableProviderFactory
java.util.List<? extends TableDescriptor<K,V,?>>	getTableDescriptors() Retrieve user-defined table descriptors contained in this table
java.util.Map<java.lang.String,java.lang.String>	toConfig(Config jobConfig) Generate configuration for this table descriptor, the generated configuration should be the complete configuration for this table that can be directly included in the job configuration.
protected void	validate() Validate that this table descriptor is constructed properly; this method is used internally.
CachingTableDescriptor<K,V>	withCacheSize(long cacheSize) Specify the max cache size for size-based eviction.
CachingTableDescriptor<K,V>	withReadTtl(java.time.Duration readTtl) Specify the TTL for each read access, ie.
CachingTableDescriptor<K,V>	withWriteAround() Specify if write-around policy should be used to bypass writing to cache for put operations.
CachingTableDescriptor<K,V>	withWriteTtl(java.time.Duration writeTtl) Specify the TTL for each write access, ie.

Methods inherited from class org.apache.samza.table.descriptors.BaseTableDescriptor

addTableConfig, getTableId, withConfig

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

PROVIDER_FACTORY_CLASS_NAME

public static final java.lang.String PROVIDER_FACTORY_CLASS_NAME

See Also:

Constant Field Values

REAL_TABLE_ID

public static final java.lang.String REAL_TABLE_ID

See Also:

Constant Field Values

CACHE_TABLE_ID

public static final java.lang.String CACHE_TABLE_ID

See Also:

Constant Field Values

READ_TTL_MS

public static final java.lang.String READ_TTL_MS

See Also:

Constant Field Values

WRITE_TTL_MS

public static final java.lang.String WRITE_TTL_MS

See Also:

Constant Field Values

CACHE_SIZE

public static final java.lang.String CACHE_SIZE

See Also:

Constant Field Values

WRITE_AROUND

public static final java.lang.String WRITE_AROUND

See Also:

Constant Field Values

Constructor Detail

CachingTableDescriptor

public CachingTableDescriptor(java.lang.String tableId,
                              TableDescriptor<K,V,?> table)

Constructs a table descriptor instance with internal cache

Parameters:

tableId - Id of the table, it must conform to pattern { @literal [\\d\\w-_]+ }

table - target table descriptor

CachingTableDescriptor

public CachingTableDescriptor(java.lang.String tableId,
                              TableDescriptor<K,V,?> table,
                              TableDescriptor<K,V,?> cache)

Constructs a table descriptor instance and specify a cache (as Table descriptor) to be used for caching. Cache get is not synchronized with put for better parallelism in the read path of caching table. As such, cache table implementation is expected to be thread-safe for concurrent accesses.

Parameters:

tableId - Id of the table, it must conform to pattern { @literal [\\d\\w-_]+ }

table - target table descriptor

cache - cache table descriptor

Method Detail

getTableDescriptors

public java.util.List<? extends TableDescriptor<K,V,?>> getTableDescriptors()

Retrieve user-defined table descriptors contained in this table

Specified by:

getTableDescriptors in class HybridTableDescriptor<K,V,CachingTableDescriptor<K,V>>

Returns:

table descriptors

withReadTtl

public CachingTableDescriptor<K,V> withReadTtl(java.time.Duration readTtl)

Specify the TTL for each read access, ie. record is expired after the TTL duration since last read access of each key.

Parameters:

readTtl - read TTL

Returns:

this descriptor

withWriteTtl

public CachingTableDescriptor<K,V> withWriteTtl(java.time.Duration writeTtl)

Specify the TTL for each write access, ie. record is expired after the TTL duration since last write access of each key.

Parameters:

writeTtl - write TTL

Returns:

this descriptor

withCacheSize

public CachingTableDescriptor<K,V> withCacheSize(long cacheSize)

Specify the max cache size for size-based eviction.

Parameters:

cacheSize - max size of the cache

Returns:

this descriptor

withWriteAround

public CachingTableDescriptor<K,V> withWriteAround()

Specify if write-around policy should be used to bypass writing to cache for put operations. This is useful when put() is the dominant operation and get() has no locality with recent puts.

Returns:

this descriptor

getProviderFactoryClassName

public java.lang.String getProviderFactoryClassName()

Description copied from class: BaseTableDescriptor

Return the fully qualified class name of the TableProviderFactory

Specified by:

getProviderFactoryClassName in class BaseTableDescriptor<K,V,CachingTableDescriptor<K,V>>

Returns:

class name of the TableProviderFactory

toConfig

public java.util.Map<java.lang.String,java.lang.String> toConfig(Config jobConfig)

Description copied from interface: TableDescriptor

Generate configuration for this table descriptor, the generated configuration should be the complete configuration for this table that can be directly included in the job configuration. Note: although the serdes may have already been set in this instance, their corresponding configuration needs to be generated centrally for consistency and efficiency reasons. Therefore the serde configuration for this table is expected to have already been generated and stored in the jobConfig.

Specified by:

toConfig in interface TableDescriptor<K,V,CachingTableDescriptor<K,V>>

Overrides:

toConfig in class BaseTableDescriptor<K,V,CachingTableDescriptor<K,V>>

Parameters:

jobConfig - job configuration

Returns:

table configuration

validate

protected void validate()

Description copied from class: BaseTableDescriptor

Validate that this table descriptor is constructed properly; this method is used internally.

Specified by:

validate in class BaseTableDescriptor<K,V,CachingTableDescriptor<K,V>>