Semantics

Data Structures
struct	JSemantics

Typedefs
typedef enum JSemanticsTemplate	JSemanticsTemplate
typedef enum JSemanticsType	JSemanticsType
typedef enum JSemanticsAtomicity	JSemanticsAtomicity
typedef enum JSemanticsConsistency	JSemanticsConsistency
typedef enum JSemanticsPersistency	JSemanticsPersistency
typedef enum JSemanticsSecurity	JSemanticsSecurity
typedef struct JSemantics	JSemantics

Enumerations
enum	JSemanticsTemplate { J_SEMANTICS_TEMPLATE_DEFAULT , J_SEMANTICS_TEMPLATE_POSIX , J_SEMANTICS_TEMPLATE_TEMPORARY_LOCAL }
enum	JSemanticsType { J_SEMANTICS_ATOMICITY , J_SEMANTICS_CONSISTENCY , J_SEMANTICS_PERSISTENCY , J_SEMANTICS_SECURITY }
enum	JSemanticsAtomicity { J_SEMANTICS_ATOMICITY_BATCH , J_SEMANTICS_ATOMICITY_OPERATION , J_SEMANTICS_ATOMICITY_NONE }
enum	JSemanticsConsistency { J_SEMANTICS_CONSISTENCY_IMMEDIATE , J_SEMANTICS_CONSISTENCY_SESSION , J_SEMANTICS_CONSISTENCY_EVENTUAL }
enum	JSemanticsPersistency { J_SEMANTICS_PERSISTENCY_STORAGE , J_SEMANTICS_PERSISTENCY_NETWORK , J_SEMANTICS_PERSISTENCY_NONE }
enum	JSemanticsSecurity { J_SEMANTICS_SECURITY_STRICT , J_SEMANTICS_SECURITY_NONE }

Functions
JSemantics *	j_semantics_new (JSemanticsTemplate template_)
JSemantics *	j_semantics_new_from_string (gchar const *template_str, gchar const *semantics_str)
JSemantics *	j_semantics_ref (JSemantics *semantics)
void	j_semantics_unref (JSemantics *semantics)
void	j_semantics_set (JSemantics *semantics, JSemanticsType key, gint value)
gint	j_semantics_get (JSemantics *semantics, JSemanticsType key)

Detailed Description

Typedef Documentation

JSemantics

typedef struct JSemantics JSemantics

JSemanticsAtomicity

typedef enum JSemanticsAtomicity JSemanticsAtomicity

JSemanticsConsistency

typedef enum JSemanticsConsistency JSemanticsConsistency

JSemanticsPersistency

typedef enum JSemanticsPersistency JSemanticsPersistency

JSemanticsSecurity

typedef enum JSemanticsSecurity JSemanticsSecurity

JSemanticsTemplate

typedef enum JSemanticsTemplate JSemanticsTemplate

JSemanticsType

typedef enum JSemanticsType JSemanticsType

Enumeration Type Documentation

JSemanticsAtomicity

enum JSemanticsAtomicity

Atomicity of batched operations.

Attention

Currently only database functions are affected by this setting.

Enumerator
J_SEMANTICS_ATOMICITY_BATCH	Consecutive operations of the same type are part of the same DB transaction. Todo: Generalize to complete batch instead of same lists.
J_SEMANTICS_ATOMICITY_OPERATION	Each operation is a transaction.
J_SEMANTICS_ATOMICITY_NONE	No transactions are used. Todo: Currently unused. Interesting when other backends support transactions.

JSemanticsConsistency

enum JSemanticsConsistency

Consistency levels describe when other clients are able to read written data.

The implemented levels are loosely based on the levels described in:

Chen Wang, Kathryn Mohror, and Marc Snir. 2021. File System Semantics Requirements of HPC Applications. In Proceedings of the 30th International Symposium on High-Performance Parallel and Distributed Computing (HPDC '21). Association for Computing Machinery, New York, NY, USA, 19–30. https://doi.org/10.1145/3431379.3460637

Attention

Mixing immediate/eventual consistencies with session-based consistency for concurrently executed batches gives no guarantees on local consistency.

Enumerator
J_SEMANTICS_CONSISTENCY_IMMEDIATE	Data is consistent immediately after the batch is executed.
J_SEMANTICS_CONSISTENCY_SESSION	Data is consistent immediately after no reference to the batch object is held anymore.
J_SEMANTICS_CONSISTENCY_EVENTUAL	The data of a corresponding batch will be eventually consistent after calling j_batch_execute(). Current implicit synchronization points are manual execution of any immediate batch, reading operations or program termination. If more control of asynchronous execution is wanted, consider using j_batch_execute_async() instead of consistency levels.

JSemanticsPersistency

enum JSemanticsPersistency

Defines which guarantees are given on the persistency of finished operations.

Enumerator
J_SEMANTICS_PERSISTENCY_STORAGE	Data of finished operations is stored on persistent storage.
J_SEMANTICS_PERSISTENCY_NETWORK	Data of finished operations arrived at a JULEA server.
J_SEMANTICS_PERSISTENCY_NONE	No guarantees on persistency.

JSemanticsSecurity

enum JSemanticsSecurity

Defines the used security model.

Attention

Currently unused.

Enumerator
J_SEMANTICS_SECURITY_STRICT
J_SEMANTICS_SECURITY_NONE

JSemanticsTemplate

enum JSemanticsTemplate

Enumerator
J_SEMANTICS_TEMPLATE_DEFAULT
J_SEMANTICS_TEMPLATE_POSIX
J_SEMANTICS_TEMPLATE_TEMPORARY_LOCAL

JSemanticsType

enum JSemanticsType

Semantics accepted by JULEA.

Enumerator
J_SEMANTICS_ATOMICITY	Atomicity of batched operations. Attention Currently only database functions are affected by this setting.
J_SEMANTICS_CONSISTENCY	Defines when data will be consistent for other clients, that is, when batches are executed.
J_SEMANTICS_PERSISTENCY	Defines which guarantees are given on the persistency of finished operations.
J_SEMANTICS_SECURITY	Defines the used security model. Attention Currently unused.

Function Documentation

j_semantics_get()

gint j_semantics_get	(	JSemantics *	semantics,
		JSemanticsType	key
	)

Gets a specific aspect of the semantics.

JSemantics* semantics;
...
j_semantics_get(semantics, J_SEMANTICS_CONSISTENCY);

Parameters

semantics	The semantics.
key	The aspect's key.

Returns

The aspect's value.

j_semantics_new()

JSemantics * j_semantics_new

(

JSemanticsTemplate

template_

)

Creates a new semantics object. Semantics objects become immutable after the first call to j_semantics_ref().

Parameters

template_

A semantics template.

Returns

A new semantics object. Should be freed with j_semantics_unref().

j_semantics_new_from_string()

JSemantics * j_semantics_new_from_string	(	gchar const *	template_str,
		gchar const *	semantics_str
	)

Creates a new semantics object from two strings. Semantics objects become immutable after the first call to j_semantics_ref().

JSemantics* semantics;
 
semantics = j_semantics_new_from_string("default", "atomicity=operation");

Parameters

template_str	A string specifying the template.
semantics_str	A string specifying the semantics.

Returns

A new semantics object. Should be freed with j_semantics_unref().

j_semantics_ref()

JSemantics * j_semantics_ref

(

JSemantics *

semantics

)

Increases the semantics' reference count. The semantics object becomes immutable after the first call to this.

Parameters

semantics

The semantics.

Returns

The semantics.

j_semantics_set()

void j_semantics_set	(	JSemantics *	semantics,
		JSemanticsType	key,
		gint	value
	)

Sets a specific aspect of the semantics.

JSemantics* semantics;
...
j_semantics_set(semantics, J_SEMANTICS_CONSISTENCY, J_SEMANTICS_CONSISTENCY_SESSION);

Parameters

semantics	The semantics.
key	The aspect's key.
value	The aspect's value.

j_semantics_unref()

void j_semantics_unref

(

JSemantics *

semantics

)

Decreases the semantics' reference count. When the reference count reaches zero, frees the memory allocated for the semantics.

Parameters

semantics

The semantics.