path: root/src/datastore/plugin_datastore_sqlite.c

 /*
     This file is part of GNUnet
     (C) 2009 Christian Grothoff (and other contributing authors)

     GNUnet is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published
     by the Free Software Foundation; either version 2, or (at your
     option) any later version.

     GNUnet is distributed in the hope that it will be useful, but
     WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     General Public License for more details.

     You should have received a copy of the GNU General Public License
     along with GNUnet; see the file COPYING.  If not, write to the
     Free Software Foundation, Inc., 59 Temple Place - Suite 330,
     Boston, MA 02111-1307, USA.
*/

/**
 * @file datastore/plugin_datastore_sqlite.c
 * @brief sqlite-based datastore backend
 * @author Christian Grothoff
 */

#include "platform.h"
#include "gnunet_statistics_service.h"
#include "plugin_datastore.h"
#include <sqlite3.h>

#define DEBUG_SQLITE GNUNET_YES

/**
 * After how many payload-changing operations
 * do we sync our statistics?
 */
#define MAX_STAT_SYNC_LAG 50

#define QUOTA_STAT_NAME gettext_noop ("file-sharing datastore utilization (in bytes)")


/**
 * Die with an error message that indicates
 * a failure of the command 'cmd' with the message given
 * by strerror(errno).
 */
#define DIE_SQLITE(db, cmd) do { GNUNET_log_from(GNUNET_ERROR_TYPE_ERROR, "sqlite", _("`%s' failed at %s:%d with error: %s\n"), cmd, __FILE__, __LINE__, sqlite3_errmsg(db->dbh)); abort(); } while(0)

/**
 * Log an error message at log-level 'level' that indicates
 * a failure of the command 'cmd' on file 'filename'
 * with the message given by strerror(errno).
 */
#define LOG_SQLITE(db, msg, level, cmd) do { GNUNET_log_from (level, "sqlite", _("`%s' failed at %s:%d with error: %s\n"), cmd, __FILE__, __LINE__, sqlite3_errmsg(db->dbh)); if (msg != NULL) GNUNET_asprintf(msg, _("`%s' failed with error: %s\n"), cmd, sqlite3_errmsg(db->dbh)); } while(0)

#define SELECT_IT_LOW_PRIORITY_1 \
  "SELECT size,type,prio,anonLevel,expire,hash,value,_ROWID_ FROM gn080 WHERE (prio = ? AND hash > ?) "\
  "ORDER BY hash ASC LIMIT 1"

#define SELECT_IT_LOW_PRIORITY_2 \
  "SELECT size,type,prio,anonLevel,expire,hash,value,_ROWID_ FROM gn080 WHERE (prio > ?) "\
  "ORDER BY prio ASC, hash ASC LIMIT 1"

#define SELECT_IT_NON_ANONYMOUS_1 \
  "SELECT size,type,prio,anonLevel,expire,hash,value,_ROWID_ FROM gn080 WHERE (prio = ? AND hash < ? AND anonLevel = 0 AND expire > %llu) "\
  " ORDER BY hash DESC LIMIT 1"

#define SELECT_IT_NON_ANONYMOUS_2 \
  "SELECT size,type,prio,anonLevel,expire,hash,value,_ROWID_ FROM gn080 WHERE (prio < ? AND anonLevel = 0 AND expire > %llu)"\
  " ORDER BY prio DESC, hash DESC LIMIT 1"

#define SELECT_IT_EXPIRATION_TIME_1 \
  "SELECT size,type,prio,anonLevel,expire,hash,value,_ROWID_ FROM gn080 WHERE (expire = ? AND hash > ?) "\
  " ORDER BY hash ASC LIMIT 1"

#define SELECT_IT_EXPIRATION_TIME_2 \
  "SELECT size,type,prio,anonLevel,expire,hash,value,_ROWID_ FROM gn080 WHERE (expire > ?) "\
  " ORDER BY expire ASC, hash ASC LIMIT 1"

#define SELECT_IT_MIGRATION_ORDER_1 \
  "SELECT size,type,prio,anonLevel,expire,hash,value,_ROWID_ FROM gn080 WHERE (expire = ? AND hash < ?) "\
  " ORDER BY hash DESC LIMIT 1"

#define SELECT_IT_MIGRATION_ORDER_2 \
  "SELECT size,type,prio,anonLevel,expire,hash,value,_ROWID_ FROM gn080 WHERE (expire < ? AND expire > %llu) "\
  " ORDER BY expire DESC, hash DESC LIMIT 1"

/**
 * After how many ms "busy" should a DB operation fail for good?
 * A low value makes sure that we are more responsive to requests
 * (especially PUTs).  A high value guarantees a higher success
 * rate (SELECTs in iterate can take several seconds despite LIMIT=1).
 *
 * The default value of 250ms should ensure that users do not experience
 * huge latencies while at the same time allowing operations to succeed
 * with reasonable probability.
 */
#define BUSY_TIMEOUT_MS 250


/**
 * Context for all functions in this plugin.
 */
struct Plugin 
{
  /**
   * Our execution environment.
   */
  struct GNUNET_DATASTORE_PluginEnvironment *env;

  /**
   * Database filename.
   */
  char *fn;

  /**
   * Native SQLite database handle.
   */
  sqlite3 *dbh;

  /**
   * Precompiled SQL for update.
   */
  sqlite3_stmt *updPrio;

  /**
   * Precompiled SQL for insertion.
   */
  sqlite3_stmt *insertContent;

  /**
   * Handle to the statistics service.
   */
  struct GNUNET_STATISTICS_Handle *statistics;
  
  /**
   * How much data are we currently storing
   * in the database?
   */
  unsigned long long payload;