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/*-
* Public Domain 2014-present 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_tiered.c
* This is an example demonstrating how to create and connect to a
* database running tiered storage.
*/
#include <test_util.h>
/*
* The number of entries we insert at a time.
*/
#define N_ENTRIES 10
/*
* Open the uri and starting at the first indicated key, insert count entries.
*/
static void
add_data(WT_SESSION *session, const char *uri, int first_key, int count)
{
WT_CURSOR *cursor;
int i;
error_check(session->open_cursor(session, uri, NULL, NULL, &cursor));
/* Insert a set of key/data pairs. */
for (i = first_key; i < first_key + count; i++) {
cursor->set_key(cursor, i);
cursor->set_value(cursor, "value");
error_check(cursor->insert(cursor));
}
error_check(cursor->close(cursor));
}
/*
* Show all entries found in the uri.
*/
static void
show_data(WT_SESSION *session, const char *uri, int nentries, const char *comment)
{
WT_CURSOR *cursor;
int key, ret;
const char *value;
printf("%s: after %d %s\n", uri, nentries, comment);
error_check(session->open_cursor(session, uri, NULL, NULL, &cursor));
while ((ret = cursor->next(cursor)) == 0) {
cursor->get_key(cursor, &key);
cursor->get_value(cursor, &value);
printf(" %d: %s\n", key, value);
}
/* We expect "not found" to end the iteration. Anything else is an error. */
if (ret == WT_NOTFOUND)
ret = 0;
error_check(ret);
error_check(cursor->close(cursor));
}
/*
* A storage source is a driver that controls access to an underlying object storage (e.g. a
* specific cloud provider). The dir_store storage source stores objects in a directory named by the
* bucket name, relative to the WiredTiger home directory.
*/
#define BUCKET_NAME "bucket"
#define BUILD_DIR "../../../"
#define STORAGE_SOURCE "dir_store"
#define LOCAL_URI "table:local_table"
#define TIERED_URI "table:tiered_table"
int
main(int argc, char *argv[])
{
WT_CONNECTION *conn;
WT_SESSION *session;
const char *home;
char buf[1024], config[1024];
home = example_setup(argc, argv);
/*
* Set up configuration for tiered storage. When tiered storage is configured, all tables
* created will be tiered by default (that is, parts will be stored in object storage), though
* tiered storage can be turned off on an individual basis.
*
* When configuring tiered storage with a cloud provider, one usually needs an access key. A
* reference to this, an "authorization token", is usually provided in the configuration string.
* This simple example uses "dir_store", a local directory based stand-in for a cloud provider,
* and no explicit access keys are needed.
*
* For learning purposes, one can single step this program and watch files created in the
* "bucket" subdirectory during the tiered checkpoint.
*/
snprintf(config, sizeof(config),
"create,"
"tiered_storage=(bucket=%s,bucket_prefix=pfx-,local_retention=5,name=%s),"
"extensions=(%s/ext/storage_sources/%s/libwiredtiger_%s.so)",
BUCKET_NAME, STORAGE_SOURCE, BUILD_DIR, STORAGE_SOURCE, STORAGE_SOURCE);
/* Create the home directory, and the bucket directory underneath it. */
(void)snprintf(
buf, sizeof(buf), "rm -rf %s && mkdir %s && mkdir %s/%s", home, home, home, BUCKET_NAME);
error_check(system(buf));
/* Configure the connection to use tiered storage. */
error_check(wiredtiger_open(home, NULL, config, &conn));
/* Open a session for the current thread's work. */
error_check(conn->open_session(conn, NULL, NULL, &session));
/* Create a table that lives locally. Tiered storage is disabled for this file. */
error_check(session->create(
session, LOCAL_URI, "key_format=i,value_format=S,tiered_storage=(name=none)"));
/* Create a table using tiered storage. */
error_check(session->create(session, TIERED_URI, "key_format=i,value_format=S"));
/* Add entries to both tables. */
add_data(session, LOCAL_URI, 0, N_ENTRIES);
add_data(session, TIERED_URI, 0, N_ENTRIES);
/*
* Do a regular checkpoint. Checkpoints are usually done in their own thread with their own
* session. Data is synchronized to local storage.
*/
error_check(session->checkpoint(session, NULL));
/* Add more entries to both tables. */
add_data(session, LOCAL_URI, N_ENTRIES, N_ENTRIES);
add_data(session, TIERED_URI, N_ENTRIES, N_ENTRIES);
/*
* Do a tiered checkpoint. For tiered tables, new data is flushed (synchronized) to the
* configured tiered storage.
*/
error_check(session->checkpoint(session, "flush_tier=(enabled)"));
/* Show the data. */
show_data(session, LOCAL_URI, 2 * N_ENTRIES, "items added");
show_data(session, TIERED_URI, 2 * N_ENTRIES, "items added and flush_tier call");
/* Add still more entries to both tables. */
add_data(session, LOCAL_URI, 2 * N_ENTRIES, N_ENTRIES);
add_data(session, TIERED_URI, 2 * N_ENTRIES, N_ENTRIES);
/*
* Another regular checkpoint. No new data is flushed to tiered storage.
*/
error_check(session->checkpoint(session, NULL));
/*
* In the tiered table, some of the entries (up to key 2 * N_ENTRIES - 1), has been put into
* tiered storage, and the rest is backed by a local file. However, all queries on the data look
* the same.
*/
show_data(session, LOCAL_URI, N_ENTRIES, "more items added");
show_data(session, TIERED_URI, N_ENTRIES, "more items added that have not been flushed");
/* Close all handles. */
error_check(session->close(session, NULL));
error_check(conn->close(conn, NULL));
return (EXIT_SUCCESS);
}
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