X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=src%2Futils_db_query.c;h=5531b25fe7fd60eb5e34300b8f2cfb0ce3cbbf2f;hb=633c3966f770e4d46651a2fe219a18d8a9907a9f;hp=868b53bf5c92e68fb24c0aaf7ae42612dd22c645;hpb=0b8442dd33105499df02180294c36d5705d596f0;p=collectd.git

diff --git a/src/utils_db_query.c b/src/utils_db_query.c
index 868b53bf..43ca2965 100644
--- a/src/utils_db_query.c
+++ b/src/utils_db_query.c
@@ -2,21 +2,26 @@
  * collectd - src/utils_db_query.c
  * Copyright (C) 2008,2009  Florian octo Forster
  *
- * This program 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; only version 2 of the License is applicable.
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
  *
- * This program 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.
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
  *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, write to the Free Software Foundation, Inc.,
- * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ * 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 OR COPYRIGHT HOLDERS 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.
  *
  * Authors:
- *   Florian octo Forster <octo at verplant.org>
+ *   Florian octo Forster <octo at collectd.org>
  **/
 
 #include "collectd.h"
@@ -39,13 +44,6 @@ struct udb_result_s
   char   **values;
   size_t   values_num;
 
-  /* Preparation area */
-  const   data_set_t *ds;
-  size_t *instances_pos;
-  size_t *values_pos;
-  char  **instances_buffer;
-  char  **values_buffer;
-
   udb_result_t *next;
 }; /* }}} */
 
@@ -58,13 +56,31 @@ struct udb_query_s /* {{{ */
   unsigned int min_version;
   unsigned int max_version;
 
-  /* Preparation area */
+  udb_result_t *results;
+}; /* }}} */
+
+struct udb_result_preparation_area_s /* {{{ */
+{
+  const   data_set_t *ds;
+  size_t *instances_pos;
+  size_t *values_pos;
+  char  **instances_buffer;
+  char  **values_buffer;
+
+  struct udb_result_preparation_area_s *next;
+}; /* }}} */
+typedef struct udb_result_preparation_area_s udb_result_preparation_area_t;
+
+struct udb_query_preparation_area_s /* {{{ */
+{
   size_t column_num;
   char *host;
   char *plugin;
   char *db_name;
 
-  udb_result_t *results;
+  cdtime_t interval;
+
+  udb_result_preparation_area_t *result_prep_areas;
 }; /* }}} */
 
 /*
@@ -171,132 +187,139 @@ static int udb_config_set_uint (unsigned int *ret_value, /* {{{ */
 /*
  * Result private functions
  */
-static void udb_result_submit (udb_result_t *r, udb_query_t *q) /* {{{ */
+static int udb_result_submit (udb_result_t *r, /* {{{ */
+    udb_result_preparation_area_t *r_area,
+    udb_query_t const *q, udb_query_preparation_area_t *q_area)
 {
   value_list_t vl = VALUE_LIST_INIT;
   size_t i;
 
-  assert (((size_t) r->ds->ds_num) == r->values_num);
-
-  DEBUG ("db query utils: udb_result_submit: r->instance_prefix = %s;",
-      (r->instance_prefix == NULL) ? "NULL" : r->instance_prefix);
-  for (i = 0; i < r->instances_num; i++)
-  {
-    DEBUG ("db query utils: udb_result_submit: r->instances_buffer[%zu] = %s;",
-        i, r->instances_buffer[i]);
-  }
+  assert (r != NULL);
+  assert (r_area->ds != NULL);
+  assert (((size_t) r_area->ds->ds_num) == r->values_num);
 
-  vl.values = (value_t *) calloc (r->ds->ds_num, sizeof (value_t));
+  vl.values = (value_t *) calloc (r_area->ds->ds_num, sizeof (value_t));
   if (vl.values == NULL)
   {
     ERROR ("db query utils: malloc failed.");
-    return;
+    return (-1);
   }
-  vl.values_len = r->ds->ds_num;
+  vl.values_len = r_area->ds->ds_num;
 
   for (i = 0; i < r->values_num; i++)
   {
-    char *endptr;
-
-    endptr = NULL;
-    errno = 0;
-    if (r->ds->ds[i].type == DS_TYPE_COUNTER)
-      vl.values[i].counter = (counter_t) strtoll (r->values_buffer[i],
-          &endptr, /* base = */ 0);
-    else if (r->ds->ds[i].type == DS_TYPE_GAUGE)
-      vl.values[i].gauge = (gauge_t) strtod (r->values_buffer[i], &endptr);
-    else
-      errno = EINVAL;
+    char *value_str = r_area->values_buffer[i];
 
-    if ((endptr == r->values_buffer[i]) || (errno != 0))
+    if (0 != parse_value (value_str, &vl.values[i], r_area->ds->ds[i].type))
     {
-      WARNING ("db query utils: udb_result_submit: Parsing `%s' as %s failed.",
-          r->values_buffer[i],
-          (r->ds->ds[i].type == DS_TYPE_COUNTER) ? "counter" : "gauge");
-      vl.values[i].gauge = NAN;
+      ERROR ("db query utils: udb_result_submit: Parsing `%s' as %s failed.",
+          value_str, DS_TYPE_TO_STRING (r_area->ds->ds[i].type));
+      errno = EINVAL;
+      return (-1);
     }
   }
 
-  vl.time = time (NULL);
-  sstrncpy (vl.host, q->host, sizeof (vl.host));
-  sstrncpy (vl.plugin, q->plugin, sizeof (vl.plugin));
-  sstrncpy (vl.plugin_instance, q->db_name, sizeof (vl.type_instance));
+  if (q_area->interval > 0)
+    vl.interval = q_area->interval;
+
+  sstrncpy (vl.host, q_area->host, sizeof (vl.host));
+  sstrncpy (vl.plugin, q_area->plugin, sizeof (vl.plugin));
+  sstrncpy (vl.plugin_instance, q_area->db_name, sizeof (vl.plugin_instance));
   sstrncpy (vl.type, r->type, sizeof (vl.type));
 
-  if (r->instance_prefix == NULL)
+  /* Set vl.type_instance {{{ */
+  if (r->instances_num <= 0)
   {
-    strjoin (vl.type_instance, sizeof (vl.type_instance),
-        r->instances_buffer, r->instances_num, "-");
+    if (r->instance_prefix == NULL)
+      vl.type_instance[0] = 0;
+    else
+      sstrncpy (vl.type_instance, r->instance_prefix,
+          sizeof (vl.type_instance));
   }
-  else
+  else /* if ((r->instances_num > 0) */
   {
-    char tmp[DATA_MAX_NAME_LEN];
+    if (r->instance_prefix == NULL)
+    {
+      strjoin (vl.type_instance, sizeof (vl.type_instance),
+          r_area->instances_buffer, r->instances_num, "-");
+    }
+    else
+    {
+      char tmp[DATA_MAX_NAME_LEN];
 
-    strjoin (tmp, sizeof (tmp), r->instances_buffer, r->instances_num, "-");
-    tmp[sizeof (tmp) - 1] = 0;
+      strjoin (tmp, sizeof (tmp), r_area->instances_buffer,
+          r->instances_num, "-");
+      tmp[sizeof (tmp) - 1] = 0;
 
-    snprintf (vl.type_instance, sizeof (vl.type_instance), "%s-%s",
-        r->instance_prefix, tmp);
+      snprintf (vl.type_instance, sizeof (vl.type_instance), "%s-%s",
+          r->instance_prefix, tmp);
+    }
   }
   vl.type_instance[sizeof (vl.type_instance) - 1] = 0;
+  /* }}} */
 
   plugin_dispatch_values (&vl);
 
   sfree (vl.values);
+  return (0);
 } /* }}} void udb_result_submit */
 
-static void udb_result_finish_result (udb_result_t *r) /* {{{ */
+static void udb_result_finish_result (udb_result_t const *r, /* {{{ */
+    udb_result_preparation_area_t *prep_area)
 {
-  if (r == NULL)
+  if ((r == NULL) || (prep_area == NULL))
     return;
 
-  r->ds = NULL;
-  sfree (r->instances_pos);
-  sfree (r->values_pos);
-  sfree (r->instances_buffer);
-  sfree (r->values_buffer);
+  prep_area->ds = NULL;
+  sfree (prep_area->instances_pos);
+  sfree (prep_area->values_pos);
+  sfree (prep_area->instances_buffer);
+  sfree (prep_area->values_buffer);
 } /* }}} void udb_result_finish_result */
 
 static int udb_result_handle_result (udb_result_t *r, /* {{{ */
-    udb_query_t *q, char **column_values)
+    udb_query_preparation_area_t *q_area,
+    udb_result_preparation_area_t *r_area,
+    udb_query_t const *q, char **column_values)
 {
   size_t i;
 
+  assert (r && q_area && r_area);
+
   for (i = 0; i < r->instances_num; i++)
-    r->instances_buffer[i] = column_values[r->instances_pos[i]];
+    r_area->instances_buffer[i] = column_values[r_area->instances_pos[i]];
 
   for (i = 0; i < r->values_num; i++)
-    r->values_buffer[i] = column_values[r->values_pos[i]];
-
-  udb_result_submit (r, q);
+    r_area->values_buffer[i] = column_values[r_area->values_pos[i]];
 
-  return (0);
+  return udb_result_submit (r, r_area, q, q_area);
 } /* }}} int udb_result_handle_result */
 
-static int udb_result_prepare_result (udb_result_t *r, /* {{{ */
+static int udb_result_prepare_result (udb_result_t const *r, /* {{{ */
+    udb_result_preparation_area_t *prep_area,
     char **column_names, size_t column_num)
 {
   size_t i;
 
-  if (r == NULL)
+  if ((r == NULL) || (prep_area == NULL))
     return (-EINVAL);
 
 #define BAIL_OUT(status) \
-  r->ds = NULL; \
-  sfree (r->instances_pos); \
-  sfree (r->values_pos); \
-  sfree (r->instances_buffer); \
-  sfree (r->values_buffer); \
+  prep_area->ds = NULL; \
+  sfree (prep_area->instances_pos); \
+  sfree (prep_area->values_pos); \
+  sfree (prep_area->instances_buffer); \
+  sfree (prep_area->values_buffer); \
   return (status)
 
   /* Make sure previous preparations are cleaned up. */
-  udb_result_finish_result (r);
-  r->instances_pos = NULL;
-  r->values_pos = NULL;
+  udb_result_finish_result (r, prep_area);
+  prep_area->instances_pos = NULL;
+  prep_area->values_pos = NULL;
 
   /* Read `ds' and check number of values {{{ */
-  r->ds = plugin_get_ds (r->type);
-  if (r->ds == NULL)
+  prep_area->ds = plugin_get_ds (r->type);
+  if (prep_area->ds == NULL)
   {
     ERROR ("db query utils: udb_result_prepare_result: Type `%s' is not "
         "known by the daemon. See types.db(5) for details.",
@@ -304,12 +327,12 @@ static int udb_result_prepare_result (udb_result_t *r, /* {{{ */
     BAIL_OUT (-1);
   }
 
-  if (((size_t) r->ds->ds_num) != r->values_num)
+  if (((size_t) prep_area->ds->ds_num) != r->values_num)
   {
     ERROR ("db query utils: udb_result_prepare_result: The type `%s' "
         "requires exactly %i value%s, but the configuration specifies %zu.",
         r->type,
-        r->ds->ds_num, (r->ds->ds_num == 1) ? "" : "s",
+        prep_area->ds->ds_num, (prep_area->ds->ds_num == 1) ? "" : "s",
         r->values_num);
     BAIL_OUT (-1);
   }
@@ -317,29 +340,36 @@ static int udb_result_prepare_result (udb_result_t *r, /* {{{ */
 
   /* Allocate r->instances_pos, r->values_pos, r->instances_buffer, and
    * r->values_buffer {{{ */
-  r->instances_pos = (size_t *) calloc (r->instances_num, sizeof (size_t));
-  if (r->instances_pos == NULL)
+  if (r->instances_num > 0)
   {
-    ERROR ("db query utils: udb_result_prepare_result: malloc failed.");
-    BAIL_OUT (-ENOMEM);
-  }
+    prep_area->instances_pos
+      = (size_t *) calloc (r->instances_num, sizeof (size_t));
+    if (prep_area->instances_pos == NULL)
+    {
+      ERROR ("db query utils: udb_result_prepare_result: malloc failed.");
+      BAIL_OUT (-ENOMEM);
+    }
 
-  r->values_pos = (size_t *) calloc (r->values_num, sizeof (size_t));
-  if (r->values_pos == NULL)
-  {
-    ERROR ("db query utils: udb_result_prepare_result: malloc failed.");
-    BAIL_OUT (-ENOMEM);
-  }
+    prep_area->instances_buffer
+      = (char **) calloc (r->instances_num, sizeof (char *));
+    if (prep_area->instances_buffer == NULL)
+    {
+      ERROR ("db query utils: udb_result_prepare_result: malloc failed.");
+      BAIL_OUT (-ENOMEM);
+    }
+  } /* if (r->instances_num > 0) */
 
-  r->instances_buffer = (char **) calloc (r->instances_num, sizeof (char *));
-  if (r->instances_buffer == NULL)
+  prep_area->values_pos
+    = (size_t *) calloc (r->values_num, sizeof (size_t));
+  if (prep_area->values_pos == NULL)
   {
     ERROR ("db query utils: udb_result_prepare_result: malloc failed.");
     BAIL_OUT (-ENOMEM);
   }
 
-  r->values_buffer = (char **) calloc (r->values_num, sizeof (char *));
-  if (r->values_buffer == NULL)
+  prep_area->values_buffer
+    = (char **) calloc (r->values_num, sizeof (char *));
+  if (prep_area->values_buffer == NULL)
   {
     ERROR ("db query utils: udb_result_prepare_result: malloc failed.");
     BAIL_OUT (-ENOMEM);
@@ -355,7 +385,7 @@ static int udb_result_prepare_result (udb_result_t *r, /* {{{ */
     {
       if (strcasecmp (r->instances[i], column_names[j]) == 0)
       {
-        r->instances_pos[i] = j;
+        prep_area->instances_pos[i] = j;
         break;
       }
     }
@@ -378,7 +408,7 @@ static int udb_result_prepare_result (udb_result_t *r, /* {{{ */
     {
       if (strcasecmp (r->values[i], column_names[j]) == 0)
       {
-        r->values_pos[i] = j;
+        prep_area->values_pos[i] = j;
         break;
       }
     }
@@ -479,12 +509,6 @@ static int udb_result_create (const char *query_name, /* {{{ */
           "result in query `%s'", query_name);
       status = -1;
     }
-    if (r->instances == NULL)
-    {
-      WARNING ("db query utils: `InstancesFrom' not given for "
-          "result in query `%s'", query_name);
-      status = -1;
-    }
     if (r->values == NULL)
     {
       WARNING ("db query utils: `ValuesFrom' not given for "
@@ -540,7 +564,8 @@ void udb_query_free_one (udb_query_t *q) /* {{{ */
  * Query public functions
  */
 int udb_query_create (udb_query_t ***ret_query_list, /* {{{ */
-    size_t *ret_query_list_len, oconfig_item_t *ci)
+    size_t *ret_query_list_len, oconfig_item_t *ci,
+    udb_query_create_callback_t cb)
 {
   udb_query_t **query_list;
   size_t        query_list_len;
@@ -592,20 +617,16 @@ int udb_query_create (udb_query_t ***ret_query_list, /* {{{ */
       status = udb_config_set_uint (&q->min_version, child);
     else if (strcasecmp ("MaxVersion", child->key) == 0)
       status = udb_config_set_uint (&q->max_version, child);
-    /* PostgreSQL compatibility code */
-    else if (strcasecmp ("MinPGVersion", child->key) == 0)
-    {
-      WARNING ("db query utils: Query `%s': The `MinPGVersion' option is "
-          "deprecated. Please use `MinVersion' instead.",
-          q->name);
-      status = udb_config_set_uint (&q->min_version, child);
-    }
-    else if (strcasecmp ("MaxPGVersion", child->key) == 0)
+
+    /* Call custom callbacks */
+    else if (cb != NULL)
     {
-      WARNING ("db query utils: Query `%s': The `MaxPGVersion' option is "
-          "deprecated. Please use `MaxVersion' instead.",
-          q->name);
-      status = udb_config_set_uint (&q->max_version, child);
+      status = (*cb) (q, child);
+      if (status != 0)
+      {
+        WARNING ("db query utils: The configuration callback failed "
+            "to handle `%s'.", child->key);
+      }
     }
     else
     {
@@ -680,63 +701,90 @@ void udb_query_free (udb_query_t **query_list, size_t query_list_len) /* {{{ */
   sfree (query_list);
 } /* }}} void udb_query_free */
 
-int udb_query_pick_from_list (oconfig_item_t *ci, /* {{{ */
+int udb_query_pick_from_list_by_name (const char *name, /* {{{ */
     udb_query_t **src_list, size_t src_list_len,
     udb_query_t ***dst_list, size_t *dst_list_len)
 {
-  const char *name;
-  udb_query_t *q;
-  udb_query_t **tmp_list;
-  size_t tmp_list_len;
   size_t i;
+  int num_added;
 
-  if ((ci == NULL) || (src_list == NULL) || (dst_list == NULL)
+  if ((name == NULL) || (src_list == NULL) || (dst_list == NULL)
       || (dst_list_len == NULL))
   {
-    ERROR ("db query utils: Invalid argument.");
+    ERROR ("db query utils: udb_query_pick_from_list_by_name: "
+        "Invalid argument.");
     return (-EINVAL);
   }
 
-  if ((ci->values_num != 1)
-      || (ci->values[0].type != OCONFIG_TYPE_STRING))
+  num_added = 0;
+  for (i = 0; i < src_list_len; i++)
   {
-    ERROR ("db query utils: The `%s' config option "
-        "needs exactly one string argument.", ci->key);
-    return (-1);
-  }
-  name = ci->values[0].value.string;
+    udb_query_t **tmp_list;
+    size_t tmp_list_len;
 
-  q = NULL;
-  for (i = 0; i < src_list_len; i++)
-    if (strcasecmp (name, src_list[i]->name) == 0)
+    if (strcasecmp (name, src_list[i]->name) != 0)
+      continue;
+
+    tmp_list_len = *dst_list_len;
+    tmp_list = (udb_query_t **) realloc (*dst_list, (tmp_list_len + 1)
+        * sizeof (udb_query_t *));
+    if (tmp_list == NULL)
     {
-      q = src_list[i];
-      break;
+      ERROR ("db query utils: realloc failed.");
+      return (-ENOMEM);
     }
 
-  if (q == NULL)
+    tmp_list[tmp_list_len] = src_list[i];
+    tmp_list_len++;
+
+    *dst_list = tmp_list;
+    *dst_list_len = tmp_list_len;
+
+    num_added++;
+  } /* for (i = 0; i < src_list_len; i++) */
+
+  if (num_added <= 0)
   {
-    ERROR ("db query utils: Cannot find query `%s'. Make sure the <%s> "
+    ERROR ("db query utils: Cannot find query `%s'. Make sure the <Query> "
         "block is above the database definition!",
-        name, ci->key);
+        name);
     return (-ENOENT);
   }
+  else
+  {
+    DEBUG ("db query utils: Added %i versions of query `%s'.",
+        num_added, name);
+  }
+
+  return (0);
+} /* }}} int udb_query_pick_from_list_by_name */
+
+int udb_query_pick_from_list (oconfig_item_t *ci, /* {{{ */
+    udb_query_t **src_list, size_t src_list_len,
+    udb_query_t ***dst_list, size_t *dst_list_len)
+{
+  const char *name;
 
-  tmp_list_len = *dst_list_len;
-  tmp_list = (udb_query_t **) realloc (*dst_list, (tmp_list_len + 1)
-      * sizeof (udb_query_t *));
-  if (tmp_list == NULL)
+  if ((ci == NULL) || (src_list == NULL) || (dst_list == NULL)
+      || (dst_list_len == NULL))
   {
-    ERROR ("db query utils: realloc failed.");
-    return (-ENOMEM);
+    ERROR ("db query utils: udb_query_pick_from_list: "
+        "Invalid argument.");
+    return (-EINVAL);
   }
-  tmp_list[tmp_list_len] = q;
-  tmp_list_len++;
 
-  *dst_list = tmp_list;
-  *dst_list_len = tmp_list_len;
+  if ((ci->values_num != 1)
+      || (ci->values[0].type != OCONFIG_TYPE_STRING))
+  {
+    ERROR ("db query utils: The `%s' config option "
+        "needs exactly one string argument.", ci->key);
+    return (-1);
+  }
+  name = ci->values[0].value.string;
 
-  return (0);
+  return (udb_query_pick_from_list_by_name (name,
+        src_list, src_list_len,
+        dst_list, dst_list_len));
 } /* }}} int udb_query_pick_from_list */
 
 const char *udb_query_get_name (udb_query_t *q) /* {{{ */
@@ -782,33 +830,45 @@ int udb_query_check_version (udb_query_t *q, unsigned int version) /* {{{ */
   return (1);
 } /* }}} int udb_query_check_version */
 
-void udb_query_finish_result (udb_query_t *q) /* {{{ */
+void udb_query_finish_result (udb_query_t const *q, /* {{{ */
+    udb_query_preparation_area_t *prep_area)
 {
+  udb_result_preparation_area_t *r_area;
   udb_result_t *r;
 
-  if (q == NULL)
+  if ((q == NULL) || (prep_area == NULL))
     return;
 
-  q->column_num = 0;
-  sfree (q->host);
-  sfree (q->plugin);
-  sfree (q->db_name);
+  prep_area->column_num = 0;
+  sfree (prep_area->host);
+  sfree (prep_area->plugin);
+  sfree (prep_area->db_name);
 
-  for (r = q->results; r != NULL; r = r->next)
-    udb_result_finish_result (r);
+  prep_area->interval = 0;
+
+  for (r = q->results, r_area = prep_area->result_prep_areas;
+      r != NULL; r = r->next, r_area = r_area->next)
+  {
+    /* this may happen during error conditions of the caller */
+    if (r_area == NULL)
+      break;
+    udb_result_finish_result (r, r_area);
+  }
 } /* }}} void udb_query_finish_result */
 
-int udb_query_handle_result (udb_query_t *q, char **column_values) /* {{{ */
+int udb_query_handle_result (udb_query_t const *q, /* {{{ */
+    udb_query_preparation_area_t *prep_area, char **column_values)
 {
+  udb_result_preparation_area_t *r_area;
   udb_result_t *r;
   int success;
   int status;
 
-  if (q == NULL)
+  if ((q == NULL) || (prep_area == NULL))
     return (-EINVAL);
 
-  if ((q->column_num < 1) || (q->host == NULL) || (q->plugin == NULL)
-      || (q->db_name == NULL))
+  if ((prep_area->column_num < 1) || (prep_area->host == NULL)
+      || (prep_area->plugin == NULL) || (prep_area->db_name == NULL))
   {
     ERROR ("db query utils: Query `%s': Query is not prepared; "
         "can't handle result.", q->name);
@@ -820,19 +880,21 @@ int udb_query_handle_result (udb_query_t *q, char **column_values) /* {{{ */
   {
     size_t i;
 
-    for (i = 0; i < q->column_num; i++)
+    for (i = 0; i < prep_area->column_num; i++)
     {
       DEBUG ("db query utils: udb_query_handle_result (%s, %s): "
           "column[%zu] = %s;",
-          q->db_name, q->name, i, column_values[i]);
+          prep_area->db_name, q->name, i, column_values[i]);
     }
   } while (0);
 #endif /* }}} */
 
   success = 0;
-  for (r = q->results; r != NULL; r = r->next)
+  for (r = q->results, r_area = prep_area->result_prep_areas;
+      r != NULL; r = r->next, r_area = r_area->next)
   {
-    status = udb_result_handle_result (r, q, column_values);
+    status = udb_result_handle_result (r, prep_area, r_area,
+        q, column_values);
     if (status == 0)
       success++;
   }
@@ -840,34 +902,39 @@ int udb_query_handle_result (udb_query_t *q, char **column_values) /* {{{ */
   if (success == 0)
   {
     ERROR ("db query utils: udb_query_handle_result (%s, %s): "
-        "All results failed.", q->db_name, q->name);
+        "All results failed.", prep_area->db_name, q->name);
     return (-1);
   }
 
   return (0);
 } /* }}} int udb_query_handle_result */
 
-int udb_query_prepare_result (udb_query_t *q, /* {{{ */
+int udb_query_prepare_result (udb_query_t const *q, /* {{{ */
+    udb_query_preparation_area_t *prep_area,
     const char *host, const char *plugin, const char *db_name,
-    char **column_names, size_t column_num)
+    char **column_names, size_t column_num, cdtime_t interval)
 {
+  udb_result_preparation_area_t *r_area;
   udb_result_t *r;
   int status;
 
-  if (q == NULL)
+  if ((q == NULL) || (prep_area == NULL))
     return (-EINVAL);
 
-  udb_query_finish_result (q);
+  udb_query_finish_result (q, prep_area);
+
+  prep_area->column_num = column_num;
+  prep_area->host = strdup (host);
+  prep_area->plugin = strdup (plugin);
+  prep_area->db_name = strdup (db_name);
 
-  q->column_num = column_num;
-  q->host = strdup (host);
-  q->plugin = strdup (plugin);
-  q->db_name = strdup (db_name);
+  prep_area->interval = interval;
 
-  if ((q->host == NULL) || (q->plugin == NULL) || (q->db_name == NULL))
+  if ((prep_area->host == NULL) || (prep_area->plugin == NULL)
+      || (prep_area->db_name == NULL))
   {
     ERROR ("db query utils: Query `%s': Prepare failed: Out of memory.", q->name);
-    udb_query_finish_result (q);
+    udb_query_finish_result (q, prep_area);
     return (-ENOMEM);
   }
 
@@ -885,12 +952,21 @@ int udb_query_prepare_result (udb_query_t *q, /* {{{ */
   } while (0);
 #endif
 
-  for (r = q->results; r != NULL; r = r->next)
+  for (r = q->results, r_area = prep_area->result_prep_areas;
+      r != NULL; r = r->next, r_area = r_area->next)
   {
-    status = udb_result_prepare_result (r, column_names, column_num);
+    if (! r_area)
+    {
+      ERROR ("db query utils: Query `%s': Invalid number of result "
+          "preparation areas.", q->name);
+      udb_query_finish_result (q, prep_area);
+      return (-EINVAL);
+    }
+
+    status = udb_result_prepare_result (r, r_area, column_names, column_num);
     if (status != 0)
     {
-      udb_query_finish_result (q);
+      udb_query_finish_result (q, prep_area);
       return (status);
     }
   }
@@ -898,4 +974,72 @@ int udb_query_prepare_result (udb_query_t *q, /* {{{ */
   return (0);
 } /* }}} int udb_query_prepare_result */
 
+udb_query_preparation_area_t *
+udb_query_allocate_preparation_area (udb_query_t *q) /* {{{ */
+{
+  udb_query_preparation_area_t   *q_area;
+  udb_result_preparation_area_t **next_r_area;
+  udb_result_t *r;
+
+  q_area = (udb_query_preparation_area_t *)malloc (sizeof (*q_area));
+  if (q_area == NULL)
+    return NULL;
+
+  memset (q_area, 0, sizeof (*q_area));
+
+  next_r_area = &q_area->result_prep_areas;
+  for (r = q->results; r != NULL; r = r->next)
+  {
+    udb_result_preparation_area_t *r_area;
+
+    r_area = (udb_result_preparation_area_t *)malloc (sizeof (*r_area));
+    if (r_area == NULL)
+    {
+      for (r_area = q_area->result_prep_areas;
+          r_area != NULL; r_area = r_area->next)
+      {
+        free (r_area);
+      }
+      free (q_area);
+      return NULL;
+    }
+
+    memset (r_area, 0, sizeof (*r_area));
+
+    *next_r_area = r_area;
+    next_r_area  = &r_area->next;
+  }
+
+  return (q_area);
+} /* }}} udb_query_preparation_area_t *udb_query_allocate_preparation_area */
+
+void
+udb_query_delete_preparation_area (udb_query_preparation_area_t *q_area) /* {{{ */
+{
+  udb_result_preparation_area_t *r_area;
+
+  if (q_area == NULL)
+    return;
+
+  r_area = q_area->result_prep_areas;
+  while (r_area != NULL)
+  {
+    udb_result_preparation_area_t *area = r_area;
+
+    r_area = r_area->next;
+
+    sfree (area->instances_pos);
+    sfree (area->values_pos);
+    sfree (area->instances_buffer);
+    sfree (area->values_buffer);
+    free (area);
+  }
+
+  sfree (q_area->host);
+  sfree (q_area->plugin);
+  sfree (q_area->db_name);
+
+  free (q_area);
+} /* }}} void udb_query_delete_preparation_area */
+
 /* vim: set sw=2 sts=2 et fdm=marker : */