(no commit message)
[oweals/gnunet.git] / src / datastore / plugin_datastore_sqlite.c
index ff4b137b78727a38205cf6c7f250414a596afd55..457f75c456271dcee61f22782bfb2a482d11e3c9 100644 (file)
@@ -4,7 +4,7 @@
 
      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
+     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
  */
 
 #include "platform.h"
-#include "gnunet_statistics_service.h"
-#include "plugin_datastore.h"
+#include "gnunet_datastore_plugin.h"
 #include <sqlite3.h>
 
-#define DEBUG_SQLITE GNUNET_NO
+#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)")
 
 /**
  * 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"), cmd, sqlite3_errmsg(db->dbh)); } while(0)
+#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 at %s:%u with error: %s"), cmd, __FILE__, __LINE__, 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 > ?) "\
@@ -91,6 +83,7 @@
 #define BUSY_TIMEOUT_MS 250
 
 
+
 /**
  * Context for all functions in this plugin.
  */
@@ -122,27 +115,20 @@ struct Plugin
   sqlite3_stmt *insertContent;
 
   /**
-   * Handle to the statistics service.
+   * Closure of the 'next_task' (must be freed if 'next_task' is cancelled).
    */
-  struct GNUNET_STATISTICS_Handle *statistics;
-  
-  /**
-   * How much data are we currently storing
-   * in the database?
-   */
-  unsigned long long payload;
+  struct NextContext *next_task_nc;
 
   /**
-   * Number of updates that were made to the
-   * payload value since we last synchronized
-   * it with the statistics service.
+   * Pending task with scheduler for running the next request.
    */
-  unsigned int lastSync;
+  GNUNET_SCHEDULER_TaskIdentifier next_task;
 
   /**
    * Should the database be dropped on shutdown?
    */
   int drop_on_shutdown;
+
 };
 
 
@@ -159,9 +145,9 @@ sq_prepare (sqlite3 * dbh, const char *zSql,
             sqlite3_stmt ** ppStmt)
 {
   char *dummy;
-  return sqlite3_prepare (dbh,
-                          zSql,
-                          strlen (zSql), ppStmt, (const char **) &dummy);
+  return sqlite3_prepare_v2 (dbh,
+                            zSql,
+                            strlen (zSql), ppStmt, (const char **) &dummy);
 }
 
 
@@ -193,13 +179,13 @@ create_indices (sqlite3 * dbh)
 
 
 
-#if 1
+#if 0
 #define CHECK(a) GNUNET_break(a)
 #define ENULL NULL
 #else
 #define ENULL &e
 #define ENULL_DEFINED 1
-#define CHECK(a) if (! a) { GNUNET_log(GNUNET_ERROR_TYPE_ERRROR, "%s\n", e); sqlite3_free(e); }
+#define CHECK(a) if (! a) { GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "%s\n", e); sqlite3_free(e); }
 #endif
 
 
@@ -237,19 +223,24 @@ database_setup (const struct GNUNET_CONFIGURATION_Handle *cfg,
                       "datastore-sqlite");
       return GNUNET_SYSERR;
     }
-  if (GNUNET_OK != GNUNET_DISK_directory_create_for_file (afsdir))
+  if (GNUNET_OK != GNUNET_DISK_file_test (afsdir))
     {
-      GNUNET_break (0);
-      GNUNET_free (afsdir);
-      return GNUNET_SYSERR;
+      if (GNUNET_OK != GNUNET_DISK_directory_create_for_file (afsdir))
+       {
+         GNUNET_break (0);
+         GNUNET_free (afsdir);
+         return GNUNET_SYSERR;
+       }
+      /* database is new or got deleted, reset payload to zero! */
+      plugin->env->duc (plugin->env->cls, 0);
     }
-  plugin->fn = GNUNET_STRINGS_to_utf8 (afsdir, strlen (afsdir),
 #ifdef ENABLE_NLS
-                                             nl_langinfo (CODESET)
+  plugin->fn = GNUNET_STRINGS_to_utf8 (afsdir, strlen (afsdir),
+                                      nl_langinfo (CODESET));
 #else
-                                             "UTF-8"   /* good luck */
+  plugin->fn = GNUNET_STRINGS_to_utf8 (afsdir, strlen (afsdir),
+                                      "UTF-8");   /* good luck */
 #endif
-                                             );
   GNUNET_free (afsdir);
   
   /* Open database and precompile statements */
@@ -267,11 +258,15 @@ database_setup (const struct GNUNET_CONFIGURATION_Handle *cfg,
   CHECK (SQLITE_OK ==
          sqlite3_exec (plugin->dbh,
                        "PRAGMA synchronous=OFF", NULL, NULL, ENULL));
+  CHECK (SQLITE_OK ==
+         sqlite3_exec (plugin->dbh,
+                       "PRAGMA auto_vacuum=INCREMENTAL", NULL, NULL, ENULL));
   CHECK (SQLITE_OK ==
          sqlite3_exec (plugin->dbh,
                        "PRAGMA count_changes=OFF", NULL, NULL, ENULL));
   CHECK (SQLITE_OK ==
-         sqlite3_exec (plugin->dbh, "PRAGMA page_size=4092", NULL, NULL, ENULL));
+         sqlite3_exec (plugin->dbh, 
+                      "PRAGMA page_size=4092", NULL, NULL, ENULL));
 
   CHECK (SQLITE_OK == sqlite3_busy_timeout (plugin->dbh, BUSY_TIMEOUT_MS));
 
@@ -339,22 +334,6 @@ database_setup (const struct GNUNET_CONFIGURATION_Handle *cfg,
 }
 
 
-/**
- * Synchronize our utilization statistics with the 
- * statistics service.
- * @param plugin the plugin context (state for this module)
- */
-static void 
-sync_stats (struct Plugin *plugin)
-{
-  GNUNET_STATISTICS_set (plugin->statistics,
-                        QUOTA_STAT_NAME,
-                        plugin->payload,
-                        GNUNET_YES);
-  plugin->lastSync = 0;
-}
-
-
 /**
  * Shutdown database connection and associate data
  * structures.
@@ -363,8 +342,6 @@ sync_stats (struct Plugin *plugin)
 static void
 database_shutdown (struct Plugin *plugin)
 {
-  if (plugin->lastSync > 0)
-    sync_stats (plugin);
   if (plugin->updPrio != NULL)
     sqlite3_finalize (plugin->updPrio);
   if (plugin->insertContent != NULL)
@@ -374,20 +351,6 @@ database_shutdown (struct Plugin *plugin)
 }
 
 
-/**
- * Get an estimate of how much space the database is
- * currently using.
- *
- * @param cls our plugin context
- * @return number of bytes used on disk
- */
-static unsigned long long sqlite_plugin_get_size (void *cls)
-{
-  struct Plugin *plugin = cls;
-  return plugin->payload;
-}
-
-
 /**
  * Delete the database entry with the given
  * row identifier.
@@ -522,7 +485,7 @@ static void
 sqlite_next_request_cont (void *cls,
                          const struct GNUNET_SCHEDULER_TaskContext *tc)
 {
-  struct NextContext * nc= cls;
+  struct NextContext * nc = cls;
   struct Plugin *plugin;
   unsigned long long rowid;
   sqlite3_stmt *stmtd;
@@ -534,9 +497,10 @@ sqlite_next_request_cont (void *cls,
   struct GNUNET_TIME_Absolute expiration;
   const GNUNET_HashCode *key;
   const void *data;
-
+  
   plugin = nc->plugin;
+  plugin->next_task = GNUNET_SCHEDULER_NO_TASK;
+  plugin->next_task_nc = NULL;
   if ( (GNUNET_YES == nc->end_it) ||
        (GNUNET_OK != (nc->prep(nc->prep_cls,
                               nc))) )
@@ -592,7 +556,7 @@ sqlite_next_request_cont (void *cls,
 
   priority = sqlite3_column_int (nc->stmt, 2);
   anonymity = sqlite3_column_int (nc->stmt, 3);
-  expiration.value = sqlite3_column_int64 (nc->stmt, 4);
+  expiration.abs_value = sqlite3_column_int64 (nc->stmt, 4);
   key = sqlite3_column_blob (nc->stmt, 5);
   nc->lastPriority = priority;
   nc->lastExpiration = expiration;
@@ -614,13 +578,26 @@ sqlite_next_request_cont (void *cls,
       nc->end_it = GNUNET_YES;
       return;
     }
+#if DEBUG_SQLITE
+  if (ret == GNUNET_NO)
+    GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG,
+                    "sqlite",
+                    "Asked to remove entry %llu (%u bytes)\n",
+                    (unsigned long long) rowid,
+                    size + GNUNET_DATASTORE_ENTRY_OVERHEAD);
+#endif
   if ( (ret == GNUNET_NO) &&
        (GNUNET_OK == delete_by_rowid (plugin, rowid)) )
     {
-      plugin->payload -= (size + GNUNET_DATASTORE_ENTRY_OVERHEAD);
-      plugin->lastSync++; 
-      if (plugin->lastSync >= MAX_STAT_SYNC_LAG)
-       sync_stats (plugin);
+      plugin->env->duc (plugin->env->cls,
+                       - (size + GNUNET_DATASTORE_ENTRY_OVERHEAD));
+#if DEBUG_SQLITE
+      GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG,
+                      "sqlite",
+                      "Removed entry %llu (%u bytes)\n",
+                      (unsigned long long) rowid,
+                      size + GNUNET_DATASTORE_ENTRY_OVERHEAD);
+#endif
     }
 }
 
@@ -645,11 +622,9 @@ sqlite_next_request (void *next_cls,
 
   if (GNUNET_YES == end_it)
     nc->end_it = GNUNET_YES;
-  GNUNET_SCHEDULER_add_continuation (nc->plugin->env->sched,
-                                    GNUNET_NO,
-                                    &sqlite_next_request_cont,
-                                    nc,
-                                    GNUNET_SCHEDULER_REASON_PREREQ_DONE);
+  nc->plugin->next_task_nc = nc;
+  nc->plugin->next_task = GNUNET_SCHEDULER_add_now (&sqlite_next_request_cont,
+                                                   nc);
 }
 
 
@@ -673,7 +648,7 @@ sqlite_plugin_put (void *cls,
                   const GNUNET_HashCode * key,
                   uint32_t size,
                   const void *data,
-                  uint32_t type,
+                  enum GNUNET_BLOCK_Type type,
                   uint32_t priority,
                   uint32_t anonymity,
                   struct GNUNET_TIME_Absolute expiration,
@@ -691,8 +666,8 @@ sqlite_plugin_put (void *cls,
                   type, 
                   GNUNET_h2s(key),
                   priority,
-                  (unsigned long long) GNUNET_TIME_absolute_get_remaining (expiration).value,
-                  (long long) expiration.value);
+                  (unsigned long long) GNUNET_TIME_absolute_get_remaining (expiration).rel_value,
+                  (long long) expiration.abs_value);
 #endif
   GNUNET_CRYPTO_hash (data, size, &vhash);
   stmt = plugin->insertContent;
@@ -700,7 +675,7 @@ sqlite_plugin_put (void *cls,
       (SQLITE_OK != sqlite3_bind_int (stmt, 2, type)) ||
       (SQLITE_OK != sqlite3_bind_int (stmt, 3, priority)) ||
       (SQLITE_OK != sqlite3_bind_int (stmt, 4, anonymity)) ||
-      (SQLITE_OK != sqlite3_bind_int64 (stmt, 5, (sqlite3_int64) expiration.value)) ||
+      (SQLITE_OK != sqlite3_bind_int64 (stmt, 5, expiration.abs_value)) ||
       (SQLITE_OK !=
        sqlite3_bind_blob (stmt, 6, key, sizeof (GNUNET_HashCode),
                           SQLITE_TRANSIENT)) ||
@@ -720,7 +695,7 @@ sqlite_plugin_put (void *cls,
       return GNUNET_SYSERR;
     }
   n = sqlite3_step (stmt);
-  if (n != SQLITE_DONE)
+  if (n != SQLITE_DONE) 
     {
       if (n == SQLITE_BUSY)
         {
@@ -733,16 +708,23 @@ sqlite_plugin_put (void *cls,
       LOG_SQLITE (plugin, msg,
                   GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK, "sqlite3_step");
       sqlite3_reset (stmt);
+      database_shutdown (plugin);
+      database_setup (plugin->env->cfg,
+                     plugin);
       return GNUNET_SYSERR;
     }
   if (SQLITE_OK != sqlite3_reset (stmt))
     LOG_SQLITE (plugin, NULL,
                 GNUNET_ERROR_TYPE_ERROR |
                 GNUNET_ERROR_TYPE_BULK, "sqlite3_reset");
-  plugin->lastSync++;
-  plugin->payload += size + GNUNET_DATASTORE_ENTRY_OVERHEAD;
-  if (plugin->lastSync >= MAX_STAT_SYNC_LAG)
-    sync_stats (plugin);
+  plugin->env->duc (plugin->env->cls,
+                   size + GNUNET_DATASTORE_ENTRY_OVERHEAD);
+#if DEBUG_SQLITE
+  GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG,
+                  "sqlite",
+                  "Stored new entry (%u bytes)\n",
+          size + GNUNET_DATASTORE_ENTRY_OVERHEAD);
+#endif
   return GNUNET_OK;
 }
 
@@ -780,7 +762,7 @@ sqlite_plugin_update (void *cls,
   int n;
 
   sqlite3_bind_int (plugin->updPrio, 1, delta);
-  sqlite3_bind_int64 (plugin->updPrio, 2, expire.value);
+  sqlite3_bind_int64 (plugin->updPrio, 2, expire.abs_value);
   sqlite3_bind_int64 (plugin->updPrio, 3, uid);
   n = sqlite3_step (plugin->updPrio);
   if (n != SQLITE_DONE)
@@ -839,7 +821,7 @@ struct IterContext
   /**
    * Desired type for blocks returned by this iterator.
    */
-  uint32_t type;
+  enum GNUNET_BLOCK_Type type;
 };
 
 
@@ -888,10 +870,10 @@ iter_next_prepare (void *cls,
 #if DEBUG_SQLITE
       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                  "Restricting to results larger than the last expiration %llu\n",
-                 (unsigned long long) nc->lastExpiration.value);
+                 (unsigned long long) nc->lastExpiration.abs_value);
 #endif
-      sqlite3_bind_int64 (ic->stmt_1, 1, nc->lastExpiration.value);
-      sqlite3_bind_int64 (ic->stmt_2, 1, nc->lastExpiration.value);
+      sqlite3_bind_int64 (ic->stmt_1, 1, nc->lastExpiration.abs_value);
+      sqlite3_bind_int64 (ic->stmt_2, 1, nc->lastExpiration.abs_value);
     }
 #if DEBUG_SQLITE
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
@@ -973,7 +955,7 @@ iter_next_prepare (void *cls,
  */
 static void
 basic_iter (struct Plugin *plugin,
-           uint32_t type,
+           enum GNUNET_BLOCK_Type type,
            int is_asc,
            int is_prio,
            int is_migr,
@@ -991,7 +973,7 @@ basic_iter (struct Plugin *plugin,
 #if DEBUG_SQLITE
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "At %llu, using queries `%s' and `%s'\n",
-             (unsigned long long) GNUNET_TIME_absolute_get ().value,
+             (unsigned long long) GNUNET_TIME_absolute_get ().abs_value,
              stmt_str_1,
              stmt_str_2);
 #endif
@@ -999,7 +981,7 @@ basic_iter (struct Plugin *plugin,
     {
       LOG_SQLITE (plugin, NULL,
                   GNUNET_ERROR_TYPE_ERROR |
-                  GNUNET_ERROR_TYPE_BULK, "sqlite3_prepare");
+                  GNUNET_ERROR_TYPE_BULK, "sqlite3_prepare_v2");
       iter (iter_cls, NULL, NULL, 0, NULL, 0, 0, 0, GNUNET_TIME_UNIT_ZERO_ABS, 0);
       return;
     }
@@ -1007,7 +989,7 @@ basic_iter (struct Plugin *plugin,
     {
       LOG_SQLITE (plugin, NULL,
                   GNUNET_ERROR_TYPE_ERROR |
-                  GNUNET_ERROR_TYPE_BULK, "sqlite3_prepare");
+                  GNUNET_ERROR_TYPE_BULK, "sqlite3_prepare_v2");
       sqlite3_finalize (stmt_1);
       iter (iter_cls, NULL, NULL, 0, NULL, 0, 0, 0, GNUNET_TIME_UNIT_ZERO_ABS, 0);
       return;
@@ -1031,13 +1013,13 @@ basic_iter (struct Plugin *plugin,
   if (is_asc)
     {
       nc->lastPriority = 0;
-      nc->lastExpiration.value = 0;
+      nc->lastExpiration.abs_value = 0;
       memset (&nc->lastKey, 0, sizeof (GNUNET_HashCode));
     }
   else
     {
       nc->lastPriority = 0x7FFFFFFF;
-      nc->lastExpiration.value = 0x7FFFFFFFFFFFFFFFLL;
+      nc->lastExpiration.abs_value = 0x7FFFFFFFFFFFFFFFLL;
       memset (&nc->lastKey, 255, sizeof (GNUNET_HashCode));
     }
   sqlite_next_request (nc, GNUNET_NO);
@@ -1057,7 +1039,7 @@ basic_iter (struct Plugin *plugin,
  */
 static void
 sqlite_plugin_iter_low_priority (void *cls,
-                                uint32_t type,
+                                enum GNUNET_BLOCK_Type type,
                                 PluginIterator iter,
                                 void *iter_cls)
 {
@@ -1084,7 +1066,7 @@ sqlite_plugin_iter_low_priority (void *cls,
  */
 static void
 sqlite_plugin_iter_zero_anonymity (void *cls,
-                                  uint32_t type,
+                                  enum GNUNET_BLOCK_Type type,
                                   PluginIterator iter,
                                   void *iter_cls)
 {
@@ -1094,9 +1076,9 @@ sqlite_plugin_iter_zero_anonymity (void *cls,
 
   now = GNUNET_TIME_absolute_get ();
   GNUNET_asprintf (&q1, SELECT_IT_NON_ANONYMOUS_1,
-                  (unsigned long long) now.value);
+                  (unsigned long long) now.abs_value);
   GNUNET_asprintf (&q2, SELECT_IT_NON_ANONYMOUS_2,
-                  (unsigned long long) now.value);
+                  (unsigned long long) now.abs_value);
   basic_iter (cls,
              type, 
              GNUNET_NO, GNUNET_YES, 
@@ -1123,7 +1105,7 @@ sqlite_plugin_iter_zero_anonymity (void *cls,
  */
 static void
 sqlite_plugin_iter_ascending_expiration (void *cls,
-                                        uint32_t type,
+                                        enum GNUNET_BLOCK_Type type,
                                         PluginIterator iter,
                                         void *iter_cls)
 {
@@ -1133,9 +1115,9 @@ sqlite_plugin_iter_ascending_expiration (void *cls,
 
   now = GNUNET_TIME_absolute_get ();
   GNUNET_asprintf (&q1, SELECT_IT_EXPIRATION_TIME_1,
-                  (unsigned long long) 0*now.value);
+                  (unsigned long long) 0*now.abs_value);
   GNUNET_asprintf (&q2, SELECT_IT_EXPIRATION_TIME_2,
-                  (unsigned long long) 0*now.value);
+                  (unsigned long long) 0*now.abs_value);
   basic_iter (cls,
              type, 
              GNUNET_YES, GNUNET_NO, 
@@ -1160,7 +1142,7 @@ sqlite_plugin_iter_ascending_expiration (void *cls,
  */
 static void
 sqlite_plugin_iter_migration_order (void *cls,
-                                   uint32_t type,
+                                   enum GNUNET_BLOCK_Type type,
                                    PluginIterator iter,
                                    void *iter_cls)
 {
@@ -1169,7 +1151,7 @@ sqlite_plugin_iter_migration_order (void *cls,
 
   now = GNUNET_TIME_absolute_get ();
   GNUNET_asprintf (&q, SELECT_IT_MIGRATION_ORDER_2,
-                  (unsigned long long) now.value);
+                  (unsigned long long) now.abs_value);
   basic_iter (cls,
              type, 
              GNUNET_NO, GNUNET_NO, 
@@ -1235,7 +1217,7 @@ all_next_prepare (void *cls,
  */
 static void
 sqlite_plugin_iter_all_now (void *cls,
-                           uint32_t type,
+                           enum GNUNET_BLOCK_Type type,
                            PluginIterator iter,
                            void *iter_cls)
 {
@@ -1249,7 +1231,7 @@ sqlite_plugin_iter_all_now (void *cls,
     {
       LOG_SQLITE (plugin, NULL,
                   GNUNET_ERROR_TYPE_ERROR |
-                  GNUNET_ERROR_TYPE_BULK, "sqlite3_prepare");
+                  GNUNET_ERROR_TYPE_BULK, "sqlite3_prepare_v2");
       iter (iter_cls, NULL, NULL, 0, NULL, 0, 0, 0, GNUNET_TIME_UNIT_ZERO_ABS, 0);
       return;
     }
@@ -1386,7 +1368,7 @@ static void
 sqlite_plugin_get (void *cls,
                   const GNUNET_HashCode * key,
                   const GNUNET_HashCode * vhash,
-                  uint32_t type,
+                  enum GNUNET_BLOCK_Type type,
                   PluginIterator iter, void *iter_cls)
 {
   struct Plugin *plugin = cls;
@@ -1404,7 +1386,7 @@ sqlite_plugin_get (void *cls,
       sqlite_plugin_iter_low_priority (cls, type, iter, iter_cls);
       return;
     }
-  GNUNET_snprintf (scratch, 256,
+  GNUNET_snprintf (scratch, sizeof (scratch),
                    "SELECT count(*) FROM gn080 WHERE hash=:1%s%s",
                    vhash == NULL ? "" : " AND vhash=:2",
                    type == 0 ? "" : (vhash ==
@@ -1456,7 +1438,7 @@ sqlite_plugin_get (void *cls,
       return;
     }
 
-  GNUNET_snprintf (scratch, 256,
+  GNUNET_snprintf (scratch, sizeof (scratch),
                    "SELECT size, type, prio, anonLevel, expire, hash, value, _ROWID_ "
                    "FROM gn080 WHERE hash=:1%s%s AND _ROWID_ >= :%d "
                    "ORDER BY _ROWID_ ASC LIMIT 1 OFFSET :d",
@@ -1508,26 +1490,53 @@ sqlite_plugin_drop (void *cls)
 }
 
 
-/**
- * Callback function to process statistic values.
- *
- * @param cls closure
- * @param subsystem name of subsystem that created the statistic
- * @param name the name of the datum
- * @param value the current value
- * @param is_persistent GNUNET_YES if the value is persistent, GNUNET_NO if not
- * @return GNUNET_OK to continue, GNUNET_SYSERR to abort iteration
- */
-static int
-process_stat_in (void *cls,
-                const char *subsystem,
-                const char *name,
-                unsigned long long value,
-                int is_persistent)
+static unsigned long long
+sqlite_plugin_get_size (void *cls)
 {
   struct Plugin *plugin = cls;
-  plugin->payload += value;
-  return GNUNET_OK;
+  sqlite3_stmt *stmt;
+  uint64_t pages;
+  uint64_t page_size;
+#if ENULL_DEFINED
+  char *e;
+#endif
+
+  if (SQLITE_VERSION_NUMBER < 3006000)
+    {
+      GNUNET_log_from (GNUNET_ERROR_TYPE_WARNING,
+                      "datastore-sqlite",
+                      _("sqlite version to old to determine size, assuming zero\n"));
+      return 0;
+    }
+  CHECK (SQLITE_OK ==
+        sqlite3_exec (plugin->dbh,
+                      "VACUUM", NULL, NULL, ENULL));
+  CHECK (SQLITE_OK ==
+        sqlite3_exec (plugin->dbh,
+                      "PRAGMA auto_vacuum=INCREMENTAL", NULL, NULL, ENULL));
+  CHECK (SQLITE_OK ==
+        sq_prepare (plugin->dbh,
+                    "PRAGMA page_count",
+                    &stmt));
+  if (SQLITE_ROW ==
+      sqlite3_step (stmt))
+    pages = sqlite3_column_int64 (stmt, 0);
+  else
+    pages = 0;
+  sqlite3_finalize (stmt);
+  CHECK (SQLITE_OK ==
+        sq_prepare (plugin->dbh,
+                    "PRAGMA page_size",
+                    &stmt));
+  CHECK (SQLITE_ROW ==
+        sqlite3_step (stmt));
+  page_size = sqlite3_column_int64 (stmt, 0);
+  sqlite3_finalize (stmt);
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+             _("Using sqlite page utilization to estimate payload (%llu pages of size %llu bytes)\n"),
+             (unsigned long long) pages,
+             (unsigned long long) page_size);
+  return  pages * page_size;
 }
                                         
 
@@ -1548,16 +1557,6 @@ libgnunet_plugin_datastore_sqlite_init (void *cls)
     return NULL; /* can only initialize once! */
   memset (&plugin, 0, sizeof(struct Plugin));
   plugin.env = env;
-  plugin.statistics = GNUNET_STATISTICS_create (env->sched,
-                                               "sqlite",
-                                               env->cfg);
-  GNUNET_STATISTICS_get (plugin.statistics,
-                        "sqlite",
-                        QUOTA_STAT_NAME,
-                        GNUNET_TIME_UNIT_MINUTES,
-                        NULL,
-                        &process_stat_in,
-                        &plugin);
   if (GNUNET_OK !=
       database_setup (env->cfg, &plugin))
     {
@@ -1596,12 +1595,19 @@ libgnunet_plugin_datastore_sqlite_done (void *cls)
   struct GNUNET_DATASTORE_PluginFunctions *api = cls;
   struct Plugin *plugin = api->cls;
 
+  if (plugin->next_task != GNUNET_SCHEDULER_NO_TASK)
+    {
+      GNUNET_SCHEDULER_cancel (plugin->next_task);
+      plugin->next_task = GNUNET_SCHEDULER_NO_TASK;
+      plugin->next_task_nc->prep (plugin->next_task_nc->prep_cls, NULL);
+      GNUNET_free (plugin->next_task_nc);
+      plugin->next_task_nc = NULL;
+    }
   fn = NULL;
   if (plugin->drop_on_shutdown)
     fn = GNUNET_strdup (plugin->fn);
   database_shutdown (plugin);
   plugin->env = NULL; 
-  plugin->payload = 0;
   GNUNET_free (api);
   if (fn != NULL)
     {