upscaledb Txn Functions

Macros
#define	UPS_TXN_READ_ONLY   1
#define	UPS_TXN_TEMPORARY   2

Typedefs
typedef struct ups_txn_t	ups_txn_t

Functions
UPS_EXPORT ups_status_t	ups_txn_begin (ups_txn_t **txn, ups_env_t *env, const char *name, void *reserved, uint32_t flags)
UPS_EXPORT const char *	ups_txn_get_name (ups_txn_t *txn)
UPS_EXPORT ups_status_t	ups_txn_commit (ups_txn_t *txn, uint32_t flags)
UPS_EXPORT ups_status_t	ups_txn_abort (ups_txn_t *txn, uint32_t flags)

Detailed Description

Macro Definition Documentation

#define UPS_TXN_READ_ONLY   1

Flag for ups_txn_begin

Definition at line 1202 of file upscaledb.h.

#define UPS_TXN_TEMPORARY   2

Definition at line 1205 of file upscaledb.h.

Typedef Documentation

typedef struct ups_txn_t ups_txn_t

Definition at line 1167 of file upscaledb.h.

Function Documentation

UPS_EXPORT ups_status_t ups_txn_abort	(	ups_txn_t *	txn,
		uint32_t	flags
	)

Aborts a Txn

This function aborts (= cancels) the sequence of Database operations.

Note that the function will fail with UPS_CURSOR_STILL_OPEN if a Cursor was attached to this Txn (with ups_cursor_create or ups_cursor_clone), and the Cursor was not closed.

Parameters

txn	Pointer to a Txn structure
flags	Optional flags for aborting the Txn, combined with bitwise OR. Unused, set to 0.

Returns

UPS_SUCCESS upon success

UPS_IO_ERROR if writing to the Database file or logfile failed

UPS_CURSOR_STILL_OPEN if there are Cursors attached to this Txn

Referenced by upscaledb::txn::abort().

UPS_EXPORT ups_status_t ups_txn_begin	(	ups_txn_t **	txn,
		ups_env_t *	env,
		const char *	name,
		void *	reserved,
		uint32_t	flags
	)

Begins a new Txn

A Txn is an atomic sequence of Database operations. With ups_txn_begin such a new sequence is started. To write all operations of this sequence to the Database use ups_txn_commit. To abort and cancel this sequence use ups_txn_abort.

In order to use Transactions, the Environment has to be created or opened with the flag UPS_ENABLE_TRANSACTIONS.

You can create as many Transactions as you want (older versions of upscaledb did not allow to create more than one Txn in parallel).

Parameters

txn	Pointer to a pointer of a Txn structure
env	A valid Environment handle
name	An optional Txn name
reserved	A reserved pointer; always set to NULL
flags	Optional flags for beginning the Txn, combined with bitwise OR. Possible flags are: UPS_TXN_READ_ONLY This Txn is read-only and will not modify the Database.

Returns

UPS_SUCCESS upon success

UPS_OUT_OF_MEMORY if memory allocation failed

Referenced by upscaledb::env::begin().

UPS_EXPORT ups_status_t ups_txn_commit	(	ups_txn_t *	txn,
		uint32_t	flags
	)

Commits a Txn

This function applies the sequence of Database operations.

Note that the function will fail with UPS_CURSOR_STILL_OPEN if a Cursor was attached to this Txn (with ups_cursor_create or ups_cursor_clone), and the Cursor was not closed.

Parameters

txn	Pointer to a Txn structure
flags	Optional flags for committing the Txn, combined with bitwise OR. Unused, set to 0.

Returns

UPS_SUCCESS upon success

UPS_IO_ERROR if writing to the file failed

UPS_CURSOR_STILL_OPEN if there are Cursors attached to this Txn

Referenced by upscaledb::txn::commit().

UPS_EXPORT const char* ups_txn_get_name

(

ups_txn_t *

txn

)

Retrieves the Txn name

Returns

NULL if the name was not assigned or if txn is invalid

Referenced by upscaledb::txn::get_name().