WT_DATA_SOURCE Struct Reference

Applications can extend WiredTiger by providing new implementations of the WT_DATA_SOURCE class. More...

Public Attributes
int(*	alter )(WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, WT_CONFIG_ARG *config)
	Callback to alter an object. More...
int(*	create )(WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, WT_CONFIG_ARG *config)
	Callback to create a new object. More...
int(*	compact )(WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, WT_CONFIG_ARG *config)
	Callback to compact an object. More...
int(*	drop )(WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, WT_CONFIG_ARG *config)
	Callback to drop an object. More...
int(*	open_cursor )(WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, WT_CONFIG_ARG *config, WT_CURSOR **new_cursor)
	Callback to initialize a cursor. More...
int(*	rename )(WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, const char *newuri, WT_CONFIG_ARG *config)
	Callback to rename an object. More...
int(*	salvage )(WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, WT_CONFIG_ARG *config)
	Callback to salvage an object. More...
int(*	size )(WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, wt_off_t *size)
	Callback to get the size of an object. More...
int(*	truncate )(WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, WT_CONFIG_ARG *config)
	Callback to truncate an object. More...
int(*	range_truncate )(WT_DATA_SOURCE *dsrc, WT_SESSION *session, WT_CURSOR *start, WT_CURSOR *stop)
	Callback to truncate a range of an object. More...
int(*	verify )(WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, WT_CONFIG_ARG *config)
	Callback to verify an object. More...
int(*	checkpoint )(WT_DATA_SOURCE *dsrc, WT_SESSION *session, WT_CONFIG_ARG *config)
	Callback to checkpoint the database. More...
int(*	terminate )(WT_DATA_SOURCE *dsrc, WT_SESSION *session)
	If non-NULL, a callback performed when the database is closed. More...
int(*	lsm_pre_merge )(WT_DATA_SOURCE *dsrc, WT_CURSOR *source, WT_CURSOR *dest)
	If non-NULL, a callback performed before an LSM merge. More...

Detailed Description

Applications can extend WiredTiger by providing new implementations of the WT_DATA_SOURCE class.

Each data source supports a different URI scheme for data sources to WT_SESSION::create, WT_SESSION::open_cursor and related methods. See Custom Data Sources for more information.

Thread safety: WiredTiger may invoke methods on the WT_DATA_SOURCE interface from multiple threads concurrently. It is the responsibility of the implementation to protect any shared data.

Applications register their implementation with WiredTiger by calling WT_CONNECTION::add_data_source.

        static WT_DATA_SOURCE my_dsrc = {my_alter, my_create, my_compact, my_drop, my_open_cursor,
          my_rename, my_salvage, my_size, my_truncate, my_range_truncate, my_verify, my_checkpoint,
          my_terminate, my_lsm_pre_merge};
        error_check(conn->add_data_source(conn, "dsrc:", &my_dsrc, NULL));

Member Data Documentation

alter

int(* WT_DATA_SOURCE::alter) (WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, WT_CONFIG_ARG *config)

Callback to alter an object.

static int
my_alter(WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, WT_CONFIG_ARG *config)

checkpoint

int(* WT_DATA_SOURCE::checkpoint) (WT_DATA_SOURCE *dsrc, WT_SESSION *session, WT_CONFIG_ARG *config)

Callback to checkpoint the database.

static int
my_checkpoint(WT_DATA_SOURCE *dsrc, WT_SESSION *session, WT_CONFIG_ARG *config)

compact

int(* WT_DATA_SOURCE::compact) (WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, WT_CONFIG_ARG *config)

Callback to compact an object.

static int
my_compact(WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, WT_CONFIG_ARG *config)

create

int(* WT_DATA_SOURCE::create) (WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, WT_CONFIG_ARG *config)

Callback to create a new object.

static int
my_create(WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, WT_CONFIG_ARG *config)

drop

int(* WT_DATA_SOURCE::drop) (WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, WT_CONFIG_ARG *config)

Callback to drop an object.

static int
my_drop(WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, WT_CONFIG_ARG *config)

lsm_pre_merge

int(* WT_DATA_SOURCE::lsm_pre_merge) (WT_DATA_SOURCE *dsrc, WT_CURSOR *source, WT_CURSOR *dest)

If non-NULL, a callback performed before an LSM merge.

Parameters

[in]	source	a cursor configured with the data being merged
[in]	dest	a cursor on the new object being filled by the merge

static int
my_lsm_pre_merge(WT_DATA_SOURCE *dsrc, WT_CURSOR *source, WT_CURSOR *dest)

open_cursor

int(* WT_DATA_SOURCE::open_cursor) (WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, WT_CONFIG_ARG *config, WT_CURSOR **new_cursor)

Callback to initialize a cursor.

typedef struct __my_cursor {
    WT_CURSOR wtcursor; /* WiredTiger cursor, must come first */
 
    /*
     * Local cursor information: for example, we might want to have a reference to the extension
     * functions.
     */
    WT_EXTENSION_API *wtext; /* Extension functions */
} MY_CURSOR;
 
static int
my_open_cursor(WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, WT_CONFIG_ARG *config,
  WT_CURSOR **new_cursor)
{
    MY_CURSOR *cursor;
    int ret;
 
    /* Allocate and initialize a WiredTiger cursor. */
    if ((cursor = calloc(1, sizeof(*cursor))) == NULL)
        return (errno);
 
    cursor->wtcursor.next = my_cursor_next;
    cursor->wtcursor.prev = my_cursor_prev;
    cursor->wtcursor.reset = my_cursor_reset;
    cursor->wtcursor.search = my_cursor_search;
    cursor->wtcursor.search_near = my_cursor_search_near;
    cursor->wtcursor.insert = my_cursor_insert;
    cursor->wtcursor.update = my_cursor_update;
    cursor->wtcursor.remove = my_cursor_remove;
    cursor->wtcursor.close = my_cursor_close;
 
    /*
     * Configure local cursor information.
     */
 
    /* Return combined cursor to WiredTiger. */
    *new_cursor = (WT_CURSOR *)cursor;
 

range_truncate

int(* WT_DATA_SOURCE::range_truncate) (WT_DATA_SOURCE *dsrc, WT_SESSION *session, WT_CURSOR *start, WT_CURSOR *stop)

Callback to truncate a range of an object.

static int
my_range_truncate(WT_DATA_SOURCE *dsrc, WT_SESSION *session, WT_CURSOR *start, WT_CURSOR *stop)

rename

int(* WT_DATA_SOURCE::rename) (WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, const char *newuri, WT_CONFIG_ARG *config)

Callback to rename an object.

static int
my_rename(WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, const char *newname,
  WT_CONFIG_ARG *config)

salvage

int(* WT_DATA_SOURCE::salvage) (WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, WT_CONFIG_ARG *config)

Callback to salvage an object.

static int
my_salvage(WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, WT_CONFIG_ARG *config)

size

int(* WT_DATA_SOURCE::size) (WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, wt_off_t *size)

Callback to get the size of an object.

static int
my_size(WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, wt_off_t *size)

terminate

int(* WT_DATA_SOURCE::terminate) (WT_DATA_SOURCE *dsrc, WT_SESSION *session)

If non-NULL, a callback performed when the database is closed.

The WT_DATA_SOURCE::terminate callback is intended to allow cleanup, the handle will not be subsequently accessed by WiredTiger.

static int
my_terminate(WT_DATA_SOURCE *dsrc, WT_SESSION *session)

truncate

int(* WT_DATA_SOURCE::truncate) (WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, WT_CONFIG_ARG *config)

Callback to truncate an object.

static int
my_truncate(WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, WT_CONFIG_ARG *config)

verify

int(* WT_DATA_SOURCE::verify) (WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, WT_CONFIG_ARG *config)

Callback to verify an object.

static int
my_verify(WT_DATA_SOURCE *dsrc, WT_SESSION *session, const char *uri, WT_CONFIG_ARG *config)