ex_thread.c

Shows how to access a database with multiple threads.

/*-
 * 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.
 */

#ifndef _WIN32
#include <pthread.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifdef _WIN32
#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_CONNECTION *conn;
        WT_SESSION *session;
        WT_CURSOR *cursor;
        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", wiredtiger_strerror(ret));

        return (NULL);
}
int
main(void)
{
        WT_CONNECTION *conn;
        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, 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);
}