Version 2.9.2
ex_thread.c

Shows how to access a database with multiple threads.

/*-
* Public Domain 2014-2016 MongoDB, Inc.
* Public Domain 2008-2014 WiredTiger, Inc.
*
* This is free and unencumbered software released into the public domain.
*
* Anyone is free to copy, modify, publish, use, compile, sell, or
* distribute this software, either in source code form or as a compiled
* binary, for any purpose, commercial or non-commercial, and by any
* means.
*
* In jurisdictions that recognize copyright laws, the author or authors
* of this software dedicate any and all copyright interest in the
* software to the public domain. We make this dedication for the benefit
* of the public at large and to the detriment of our heirs and
* successors. We intend this dedication to be an overt act of
* relinquishment in perpetuity of all present and future rights to this
* software under copyright law.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*
* ex_thread.c
* This is an example demonstrating how to create and access a simple
* table from multiple threads.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifndef _WIN32
#include <pthread.h>
#else
#include "windows_shim.h"
#endif
#include <wiredtiger.h>
static const char *home;
void *scan_thread(void *arg);
#define NUM_THREADS 10
void *
scan_thread(void *conn_arg)
{
WT_CURSOR *cursor;
WT_SESSION *session;
const char *key, *value;
int ret;
conn = conn_arg;
ret = conn->open_session(conn, NULL, NULL, &session);
ret = session->open_cursor(
session, "table:access", NULL, NULL, &cursor);
/* Show all records. */
while ((ret = cursor->next(cursor)) == 0) {
ret = cursor->get_key(cursor, &key);
ret = cursor->get_value(cursor, &value);
printf("Got record: %s : %s\n", key, value);
}
if (ret != WT_NOTFOUND)
fprintf(stderr,
"WT_CURSOR.next: %s\n", session->strerror(session, ret));
return (NULL);
}
int
main(void)
{
WT_SESSION *session;
WT_CURSOR *cursor;
pthread_t threads[NUM_THREADS];
int i, ret;
/*
* Create a clean test directory for this run of the test program if the
* environment variable isn't already set (as is done by make check).
*/
if (getenv("WIREDTIGER_HOME") == NULL) {
home = "WT_HOME";
ret = system("rm -rf WT_HOME && mkdir WT_HOME");
} else
home = NULL;
if ((ret = wiredtiger_open(home, NULL, "create", &conn)) != 0)
fprintf(stderr, "Error connecting to %s: %s\n",
home == NULL ? "." : home, wiredtiger_strerror(ret));
/* Note: further error checking omitted for clarity. */
ret = conn->open_session(conn, NULL, NULL, &session);
ret = session->create(session, "table:access",
"key_format=S,value_format=S");
ret = session->open_cursor(session, "table:access", NULL,
"overwrite", &cursor);
cursor->set_key(cursor, "key1");
cursor->set_value(cursor, "value1");
ret = cursor->insert(cursor);
ret = session->close(session, NULL);
for (i = 0; i < NUM_THREADS; i++)
ret = pthread_create(&threads[i], NULL, scan_thread, conn);
for (i = 0; i < NUM_THREADS; i++)
ret = pthread_join(threads[i], NULL);
ret = conn->close(conn, NULL);
return (ret == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
}