path: root/src/datastore/plugin_datastore_postgres.c

/*
     This file is part of GNUnet
     (C) 2009, 2010 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 3, 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_postgres.c
 * @brief postgres-based datastore backend
 * @author Christian Grothoff
 */

#include "platform.h"
#include "plugin_datastore.h"
#include <postgresql/libpq-fe.h>

#define DEBUG_POSTGRES GNUNET_NO

#define SELECT_IT_LOW_PRIORITY "(SELECT size, type, prio, anonLevel, expire, hash, value, oid FROM gn080 "\
                               "WHERE (prio = $1 AND oid > $2) "			\
                               "ORDER BY prio ASC,oid ASC LIMIT 1) "\
                               "UNION "\
                               "(SELECT size, type, prio, anonLevel, expire, hash, value, oid FROM gn080 "\
                               "WHERE (prio > $1 AND oid != $2)"\
                               "ORDER BY prio ASC,oid ASC LIMIT 1)"\
                               "ORDER BY prio ASC,oid ASC LIMIT 1"

#define SELECT_IT_NON_ANONYMOUS "(SELECT size, type, prio, anonLevel, expire, hash, value, oid FROM gn080 "\
                                "WHERE (prio = $1 AND oid < $2)"\
                                " AND anonLevel=0 ORDER BY prio DESC,oid DESC LIMIT 1) "\
                                "UNION "\
                                "(SELECT size, type, prio, anonLevel, expire, hash, value, oid FROM gn080 "\
                                "WHERE (prio < $1 AND oid != $2)"\
                                " AND anonLevel=0 ORDER BY prio DESC,oid DESC LIMIT 1) "\
                                "ORDER BY prio DESC,oid DESC LIMIT 1"

#define SELECT_IT_EXPIRATION_TIME "(SELECT size, type, prio, anonLevel, expire, hash, value, oid FROM gn080 "\
                                  "WHERE (expire = $1 AND oid > $2) "\
                                  "ORDER BY expire ASC,oid ASC LIMIT 1) "\
                                  "UNION "\
                                  "(SELECT size, type, prio, anonLevel, expire, hash, value, oid FROM gn080 "\
                                  "WHERE (expire > $1 AND oid != $2) "		\
                                  "ORDER BY expire ASC,oid ASC LIMIT 1)"\
                                  "ORDER BY expire ASC,oid ASC LIMIT 1"


#define SELECT_IT_MIGRATION_ORDER "(SELECT size, type, prio, anonLevel, expire, hash, value, oid FROM gn080 "\
                                  "WHERE (expire = $1 AND oid < $2)"\
                                  " AND expire > $3 AND type!=3"\
                                  " ORDER BY expire DESC,oid DESC LIMIT 1) "\
                                  "UNION "\
                                  "(SELECT size, type, prio, anonLevel, expire, hash, value, oid FROM gn080 "\
                                  "WHERE (expire < $1 AND oid != $2)"		\
                                  " AND expire > $3 AND type!=3"\
                                  " ORDER BY expire DESC,oid DESC LIMIT 1)"\
                                  "ORDER BY expire DESC,oid 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 1s should ensure that users do not experience
 * huge latencies while at the same time allowing operations to succeed
 * with reasonable probability.
 */
#define BUSY_TIMEOUT GNUNET_TIME_UNIT_SECONDS


struct NextRequestClosure
{
  struct Plugin *plugin;
  PluginIterator iter;
  void *iter_cls;
  const char *paramValues[5];
  const char *pname;
  int paramLengths[5];
  int nparams; // nparams
  struct GNUNET_TIME_Absolute now;
  GNUNET_HashCode key;
  GNUNET_HashCode vhash;
  long long count;
  long long off;
  long long limit_off;
  unsigned long long total;
  unsigned long long last_expire;
  unsigned int last_rowid; // last_rowid
  unsigned int last_prio;
  enum GNUNET_BLOCK_Type type;
  int end_it;
};


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

  /**
   * Native Postgres database handle.
   */
  PGconn *dbh;

  /**
   * Closure of the 'next_task' (must be freed if 'next_task' is cancelled).
   */
  struct NextRequestClosure *next_task_nc;

  /**
   * Pending task with scheduler for running the next request.
   */
  GNUNET_SCHEDULER_TaskIdentifier next_task;

  unsigned long long payload;

  unsigned int lastSync;
  
};


/**
 * Check if the result obtained from Postgres has
 * the desired status code.  If not, log an error, clear the
 * result and return GNUNET_SYSERR.
 * 
 * @return GNUNET_OK if the result is acceptable
 */
static int
check_result (struct Plugin *plugin,
	      PGresult * ret,
              int expected_status,
              const char *command, const char *args, int line)
{
  if (ret == NULL)
    {
      GNUNET_log_from (GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
		       "datastore-postgres",
		       "Postgres failed to allocate result for `%s:%s' at %d\n",
		       command, args, line);
      return GNUNET_SYSERR;
    }
  if (PQresultStatus (ret) != expected_status)
    {
      GNUNET_log_from (GNUNET_ERROR_TYPE_ERROR