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/*-
* Public Domain 2008-2012 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_stat.c
* This is an example demonstrating how to query a database's statistics.
*/
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <wiredtiger.h>
int print_cursor(WT_CURSOR *);
int print_database_stats(WT_SESSION *);
int print_file_stats(WT_SESSION *);
int print_overflow_pages(WT_SESSION *);
int get_stat(WT_CURSOR *cursor, int stat_field, uint64_t *valuep);
int print_derived_stats(WT_SESSION *);
const char *home = "WT_TEST";
/*! [statistics display function] */
int
print_cursor(WT_CURSOR *cursor)
{
const char *desc, *pvalue;
uint64_t value;
int ret;
while ((ret = cursor->next(cursor)) == 0 &&
(ret = cursor->get_value(cursor, &desc, &pvalue, &value)) == 0)
if (value != 0)
printf("%s=%s\n", desc, pvalue);
return (ret == WT_NOTFOUND ? 0 : ret);
}
/*! [statistics display function] */
int
print_database_stats(WT_SESSION *session)
{
WT_CURSOR *cursor;
int ret;
/*! [statistics database function] */
if ((ret = session->open_cursor(session,
"statistics:", NULL, NULL, &cursor)) != 0)
return (ret);
ret = print_cursor(cursor);
ret = cursor->close(cursor);
/*! [statistics database function] */
return (ret);
}
int
print_file_stats(WT_SESSION *session)
{
WT_CURSOR *cursor;
int ret;
/*! [statistics table function] */
if ((ret = session->open_cursor(session,
"statistics:table:access", NULL, NULL, &cursor)) != 0)
return (ret);
ret = print_cursor(cursor);
ret = cursor->close(cursor);
/*! [statistics table function] */
return (ret);
}
int
print_overflow_pages(WT_SESSION *session)
{
/*! [statistics retrieve by key] */
WT_CURSOR *cursor;
const char *desc, *pvalue;
uint64_t value;
int ret;
if ((ret = session->open_cursor(session,
"statistics:table:access", NULL, NULL, &cursor)) != 0)
return (ret);
cursor->set_key(cursor, WT_STAT_DSRC_BTREE_OVERFLOW);
ret = cursor->search(cursor);
ret = cursor->get_value(cursor, &desc, &pvalue, &value);
printf("%s=%s\n", desc, pvalue);
ret = cursor->close(cursor);
/*! [statistics retrieve by key] */
return (ret);
}
/*! [statistics calculation helper function] */
int
get_stat(WT_CURSOR *cursor, int stat_field, uint64_t *valuep)
{
const char *desc, *pvalue;
int ret;
cursor->set_key(cursor, stat_field);
if ((ret = cursor->search(cursor)) != 0)
return (ret);
return (cursor->get_value(cursor, &desc, &pvalue, valuep));
}
/*! [statistics calculation helper function] */
int
print_derived_stats(WT_SESSION *session)
{
WT_CURSOR *cursor;
int ret;
/*! [statistics calculate open table stats] */
if ((ret = session->open_cursor(session,
"statistics:table:access", NULL, NULL, &cursor)) != 0)
return (ret);
/*! [statistics calculate open table stats] */
{
/*! [statistics calculate table fragmentation] */
uint64_t ckpt_size, file_size;
ret = get_stat(cursor, WT_STAT_DSRC_BLOCK_CHECKPOINT_SIZE, &ckpt_size);
ret = get_stat(cursor, WT_STAT_DSRC_BLOCK_SIZE, &file_size);
printf("File is %d%% fragmented\n",
(int)(100 * (file_size - ckpt_size) / file_size));
/*! [statistics calculate table fragmentation] */
}
{
/*! [statistics calculate write amplification] */
uint64_t app_writes, fs_writes;
ret = get_stat(cursor, WT_STAT_DSRC_CACHE_BYTES_WRITE, &fs_writes);
ret = get_stat(cursor, WT_STAT_DSRC_CACHE_BYTES_CHANGED, &app_writes);
printf("Write amplification is %.2lf\n",
(double)fs_writes / app_writes);
/*! [statistics calculate write amplification] */
}
ret = cursor->close(cursor);
return (ret);
}
int
main(void)
{
WT_CONNECTION *conn;
WT_CURSOR *cursor;
WT_SESSION *session;
int ret;
ret = wiredtiger_open(home, NULL, "create", &conn);
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, NULL, &cursor);
cursor->set_key(cursor, "key");
cursor->set_value(cursor, "value");
ret = cursor->insert(cursor);
cursor->close(cursor);
ret = session->checkpoint(session, NULL);
ret = print_database_stats(session);
ret = print_file_stats(session);
ret = print_overflow_pages(session);
ret = print_derived_stats(session);
return (conn->close(conn, NULL) == 0 ? ret : EXIT_FAILURE);
}
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